Kyushu University Academic Staff Educational and Research Activities Database
List of Papers
Kouichi Sakurai Last modified date:2021.07.06

Professor / Mathematical Informatics / Department of Informatics / Faculty of Information Science and Electrical Engineering


Papers
1. Mosarrat Jahan, Mohsen Rezvani, Qianrui Zhao, Partha Sarathi Roy, Kouichi Sakurai, Aruna Seneviratne, Sanjay Jha, Light Weight Write Mechanism for Cloud Data, IEEE Transactions on Parallel and Distributed Systems, 10.1109/TPDS.2017.2782253, 29, 5, 1131-1146, 2018.05, Outsourcing data to the cloud for computation and storage has been on the rise in recent years. In this paper we investigate the problem of supporting write operation on the outsourced data for clients using mobile devices. We consider the Ciphertext-Policy Attribute-based Encryption (CP-ABE) scheme as it is well suited to support access control in outsourced cloud environments. One shortcoming of CP-ABE is that users can modify the access policy specified by the data owner if write operations are incorporated in the scheme. We propose a protocol for collaborative processing of outsourced data that enables the authorized users to perform write operation without being able to alter the access policy specified by the data owner. Our scheme is accompanied with a light weight signature scheme and simple, inexpensive user revocation mechanism to make it suitable for processing on resource-constrained mobile devices. The implementation and detailed performance analysis of the scheme indicate the suitability of the proposed scheme for real mobile applications. Moreover, the security analysis demonstrates that the security properties of the system are not compromised..
2. Jiawei Su, Danilo Vasconcellos Vargas, Kouichi Sakurai, One Pixel Attack for Fooling Deep Neural Networks, IEEE Transactions on Evolutionary Computation, 10.1109/TEVC.2019.2890858, 23, 5, 828-841, 2019.10, Recent research has revealed that the output of deep neural networks (DNNs) can be easily altered by adding relatively small perturbations to the input vector. In this paper, we analyze an attack in an extremely limited scenario where only one pixel can be modified. For that we propose a novel method for generating one-pixel adversarial perturbations based on differential evolution (DE). It requires less adversarial information (a black-box attack) and can fool more types of networks due to the inherent features of DE. The results show that 67.97% of the natural images in Kaggle CIFAR-10 test dataset and 16.04% of the ImageNet (ILSVRC 2012) test images can be perturbed to at least one target class by modifying just one pixel with 74.03% and 22.91% confidence on average. We also show the same vulnerability on the original CIFAR-10 dataset. Thus, the proposed attack explores a different take on adversarial machine learning in an extreme limited scenario, showing that current DNNs are also vulnerable to such low dimension attacks. Besides, we also illustrate an important application of DE (or broadly speaking, evolutionary computation) in the domain of adversarial machine learning: creating tools that can effectively generate low-cost adversarial attacks against neural networks for evaluating robustness..
3. Wissam Razouk, Daniele Sgandurra, Kouichi Sakurai, A new security middleware architecture based on fog computing and cloud to support IoT constrained devices, ACM International Conference Proceeding Series, 10.1145/3109761.3158413, 2017.10, The increase of sensitive data in the current Internet of Things (IoT) raises demands of computation, communication and storage capabilities. Indeed, thanks to RFID tags and wireless sensor networks, anything can be part of IoT. As a result, a large amount of data is generated, which is hard for many IoT devices to handle, as many IoT devices are resource-constrained and cannot use the existing standard security protocols. Cloud computing might seem like a convenient solution, since it offers on-demand access to a shared pool of resources such as processors, storage, applications and services. However this comes as a cost, as unnecessary communications not only burden the core network, but also the data center in the cloud. Therefore, considering suitable approaches such as fog computing and security middleware solutions is crucial. In this paper, we propose a novel middleware architecture to solve the above issues, and discuss the generic concept of using fog computing along with cloud in order to achieve a higher security level. Our security middleware acts as a smart gateway as it is meant to pre-process data at the edge of the network. Depending on the received information, data might either be processed and stored locally on fog or sent to the cloud for further processing. Moreover, in our scheme, IoT constrained devices communicate through the proposed middleware, which provide access to more computing power and enhanced capability to perform secure communications. We discuss these concepts in detail, and explain how our proposal is effective to cope with some of the most relevant IoT security challenges..
4. Rohit Ahuja, Sraban Kumar Mohanty, Kouichi Sakurai, A scalable attribute-set-based access control with both sharing and full-fledged delegation of access privileges in cloud computing, COMPUTERS & ELECTRICAL ENGINEERING, 10.1016/j.compeleceng.2016.11.028, 57, 241-256, 2017.01, The benefits of cloud computing motivate enterprises to migrate their IT infrastructure on cloud servers. Enterprise needs to entrust untrusted cloud service provider, which gives rise to various security and privacy concerns. To address these concerns, numerous schemes in cloud computing employed attribute-based encryption schemes. However, existing schemes are neither flexible enough to provide users complete liberty on delegation of their access privileges nor grant shared access privileges among users of a group to jointly address a responsibility. This paper introduces hierarchical attribute-set-based access control scheme by employing ciphertext-policy attribute-set-based encryption with a hierarchical structure of users to achieve scalability. The proposed scheme simultaneously achieves the notion of fine-grained cum flexible access control, privacy preserving, efficient data utilization and imperatively provides users full-fledged liberty on delegation of their access privileges. Furthermore, we formally prove that proposed scheme is secure under decisional bilinear Diffie-Hellman assumption. (C) 2016 Elsevier Ltd. All rights reserved..
5. Samiran Bag, Sushmita Ruj, Kouichi Sakurai, Bitcoin Block Withholding Attack: Analysis and Mitigation, IEEE Transactions on Information Forensics and Security, 10.1109/TIFS.2016.2623588, 12, 8, 1967-1978, 2017.08, We address two problems: First, we study a variant of block withholding (BWH) attack in Bitcoins and second, we propose solutions to prevent all existing types of BWH attacks in Bitcoins. We analyze the strategies of a selfish Bitcoin miner who in connivance with one pool attacks another pool and receives reward from the former mining pool for attacking the latter. We name this attack as 'sponsored block withholding attack.' We present detailed quantitative analysis of the monetary incentive that a selfish miner can earn by adopting this strategy under different scenarios. We prove that under certain conditions, the attacker can maximize her revenue by adopting some strategies and by utilizing her computing power wisely. We also show that an attacker may use this strategy for attacking both the pools for earning higher amount of incentives. More importantly, we present a strategy that can effectively counter block withholding attack in any mining pool. First, we propose a generic scheme that uses cryptographic commitment schemes to counter BWH attack. Then, we suggest an alternative implementation of the same scheme using hash function. Our scheme protects a pool from rogue miners as well as rogue pool administrators. The scheme and its variant defend against BWH attack by making it impossible for the miners to distinguish between a partial proof of work and a complete proof of work. The scheme is so designed that the administrator cannot cheat on the entire pool. The scheme can be implemented by making minor changes to existing Bitcoin protocol. We also analyze the security of the scheme..
6. Hiroaki Anada, Junpei Kawamoto, Chenyutao Ke, Kirill Morozov, Kouichi Sakurai, Cross-group secret sharing scheme for secure usage of cloud storage over different providers and regions, JOURNAL OF SUPERCOMPUTING, 10.1007/s11227-017-2009-7, 73, 10, 4275-4301, 2017.10, With the spread of the Internet, more and more data are being stored in the cloud. Here the technique of secret sharing can be naturally applied in order to provide both security and availability of the stored data, hereby reducing the risks of data leakage and data loss. The privacy property of secret sharing ensures protection against unauthorized access, while protection against data loss may be attained by distributing shares to the servers located in different regions. However, there is still a problem: If we naively employ the secret sharing technique without regarding to whom the cloud servers belong, a dishonest provider can obtain the secret data by collecting enough shares from its servers. In this scenario, there is a need to distribute shares over cloud services operated by different providers. In this paper, we propose a simple secret sharing technique, a cross-group secret sharing (CGSS), which is suitable for storing the data on cloud storage distributed over different groups-that is, different providers and regions. By combining an -out-of-m threshold secret sharing scheme with a k-out-of-n threshold secret sharing scheme using a symmetric-key encryption scheme, we construct the CGSS scheme that forces k shares to be collected from groups. Compared with the previous works, our scheme attains the functionality with reasonable computation. We also formalize the problem of allocating shares over different providers and regions as an optimization problem and show the design principles, which one must follow, when applying our proposal in practical settings. An experiment on real IaaS systems shows effectiveness of our proposed scheme, CGSS..
7. Pinaki Sarkar, Morshed Uddin Chowdhury, Kouichi Sakurai, Secure combinatorial key predistribution scheme for sensor networks by regulating frequencies: magneto optic sensors, CONCURRENCY AND COMPUTATION-PRACTICE & EXPERIENCE, 10.1002/cpe.4017, 29, 23, 2017.12, Low cost, decentralized architecture and ad hoc nature are a few desirable properties of wireless sensor networks that make them well suited for gathering sensitive information in hazardous deployment grounds. Existing security protocols exploit various cryptographic tools to strengthen their security. Not many works focus on constraints faced by an adversary. One such constraint being practical difficulties to trace a particular frequency band from a large range of unknown frequencies, specially in unharmonious geographical locations. Our research capitalizes on this weakness encountered by an adversary and preassigns nodes with multiple frequency bands from a wide range of frequencies allocated to the network. Deployed nodes can discover these bands during set network setup phase by a simple trick. Nodes are to internally switch their frequency bands depending on parametric variation that are caused by an (external) impulse. Experiments conducted using magneto optic sensors confirm that any variation of their parameter affects frequencies of emergent waves. Similar behavior is expected from application specific sensors. Frequency regulation (FR) concept is applied to combinatorial key predistribution schemes (KPS) having (regular) degree r. Depending on r and each node's capability to switch internal frequencies, nodes are preallocated with n frequency bands. This naturally partitions the (distributed) network and results in improved resilience. Combining our FR concept to a KPS where the number of shared key between a pair of nodes is at most one ( 1) may yield best case scenario of an ideally resilient key predistribution. Our analysis of systems that combines FR idea with KPS where >1 leads to an optimized key-band distribution argument and drastic resilience improvements. Results of simulations conducted assuming real-life scenario ascertain our analysis and establishes superior performance of our protocols as compared to prominent ones..
8. Takanori Yasuda, Kouichi Sakurai, A multivariate encryption scheme with Rainbow, Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics), 10.1007/978-3-319-29814-6_19, 9543, 236-251, 2016.03, Multivariate Public Key Cryptosystems (MPKC) are a candidate of post-quantum cryptography. The MPKC signature scheme Rainbow is endowed of efficient signature generation and verification, while no major attack has been reported so far. In this paper, we propose a MPKC encryption scheme based on Rainbow. The public key of Rainbow is a surjective polynomial map, whereas the encryption scheme requires an injective polynomial map. We explain how to change the public key of Rainbow to an injective map..
9. Tomohisa Ishikawa, Kouichi Sakurai, A study of security management with cyber insurance, ACM IMCOM 2016: Proceedings of the 10th International Conference on Ubiquitous Information Management and Communication, 10.1145/2857546.2857615, 2016.01, Since the recent security breach requires the intensification of security management, the documents, describing the best practice of security management, are published by experts. However, the implementations of all best practice are tough because of the cost and the difficulty of cost-effective security investment. This paper discusses the security management theory with cyber risk insurance, especially the effectiveness of cyber risk insurance by Monte Carlo simulation approach..
10. Takanori Suga, Takashi Nishide, Kouichi Sakurai, Character-based symmetric searchable encryption and its implementation and experiment on mobile devices, Security and Communication Networks, 10.1002/sec.876, 9, 12, 1717-1725, 2016.08, Searchable encryption allows us to perform a keyword search over encrypted data. However, we cannot efficiently perform some complex search (e.g., a wildcard search) with traditional searchable encryption schemes because they can deal with only equality matches. Our symmetric searchable encryption can deal with partial matches. This allows us to efficiently perform a wildcard search, partial match search, and so on. We also examine the feasibility of our scheme by experiments on a smartphone and tablet, and confirm our scheme can be used in these environments. Availability on portable devices will offer high convenience. Copyright © 2013 John Wiley &
Sons, Ltd..
11. Chenyutao Ke, Hiroaki Anada, Junpei Kawamoto, Kirill Morozov, Kouichi Sakurai, Cross-group secret sharing for secure cloud storage service, ACM IMCOM 2016: Proceedings of the 10th International Conference on Ubiquitous Information Management and Communication, 10.1145/2857546.2857610, 2016.01, With the spread of the Internet, many mobile devices are used in our daily lives, such as tablets and mobile phones. Then, personal data are often saved on data servers of the storage providers such as Amazon, Google, Yahoo, Baidu and others. In this context, the secret sharing can be used to store personal data onto several providers, simultaneously reducing the risk of data loss, the data leakage to unauthorized parties, and data falsification. Secret sharing is one of the solutions to combine security and availability in the distributed storage. However, few works considered servers' affiliations, and specifically, the problem that a malicious provider may recover secret data illegally through manipulation on servers that hold enough shares to recover the secret. In this paper, to resolve the problem, we propose a two-threshold secret sharing scheme in order to enforce a new type of cross-group policy. By combining t-out-of-m providers' secret sharing scheme and a k-out-of-n servers' secret sharing scheme via an one-way function or an one-time pad, we construct a scheme that forces k shares to be collected from m groups. Compared with previous work, our scheme can attain the functionalities of proactively updating shares and adding new shares with simple computation..
12. Ziyi Li, Junpei Kawamoto, Yaokai Feng, Kouichi Sakurai, Cyberbullying detection using parent-child relationship between comments, ACM International Conference Proceeding Series, 10.1145/3011141.3011182, 325-334, 2016.11, Cyberbullying is a underlying problem in social networking service, threatening users' mental and physical health. Previous research on automated cyberbullying detection is mostly textual or social based methods. Cyberbullying content is identified through a set of textual features within the content in the former method and through social information surrounding the content in the latter method. Those methods can not cater difierent cyberbullying standard for individual SNS user since each content is evaluated using same features. Therefore, in this article we propose a automated cyberbullying detection method that utilises the parent-child relationship between comments to capture the reaction from a third party to detect cyberbullying comments. We were able to improve the effectiveness of cyberbullyingdetection using only publicly available data..
13. Binanda Sengupta, Samiran Bag, Kouichi Sakurai, Sushmita Ruj, Retricoin: Bitcoin based on compact proofs of retrievability, ACM International Conference Proceeding Series, 10.1145/2833312.2833317, 04-07-, 2016.01, Bitcoin [24] is a fully decentralized electronic cash system. The generation of the proof-of-work in Bitcoin requires large amount of computing resources. However, this huge amount of energy is wasted as one cannot make something useful out of it. In this paper, we propose a scheme called Retricoin which replaces the heavy computational proof-of-work of Bitcoin by proofs of retrievability that have practical benefits. To guarantee the availability of an important but large file, we distribute the segments of the file among the users in the Bitcoin network. Every user who wants to mine Bitcoins must store a considerable portion of this file and prove her storage to other peers in the network using proofs of retrievability. The file can be constructed at any point of time from the users storing their respective segments untampered. Retricoin is more efficient than the existing Permacoin scheme [23] in terms of storage overhead and network bandwidth required to broadcast the proof to the Bitcoin network. The verification time in our scheme is comparable to that of Permacoin and reasonable for all practical purposes. We also design an algorithm to let the miners in a group (or pool) mine collectively..
14. Takanori Yasuda, Xavier Dahan, Yun-Ju Huang, Tsuyoshi Takagi, Kouichi Sakurai, A multivariate quadratic challenge toward post-quantum generation cryptography, ACM Communications in Computer Algebra, 10.1145/2850449.2850462, 49, 3, 105-107, 2015.09, Multivariate polynomials over finite fields have found applications in Public Key Cryptography (PKC) where the hardness to find solutions provides the "one-way function" indispensable to such cryptosystems. Several schemes for both encryption and signature have been proposed, many of which are using quadratic (degree 2) polynomials. Finding a solution to such systems in general is called MQ problem, which easiest "generic" instances are NP-hard. An important feature of this Multivariate Pubic Key Cryptography (MPKC) is the resistance to quantum computers: no faster quantum algorithm than classical ones to solve MQ problem is known. Besides being thereby a candidate for Post-Quantum Cryptography, signatures are much shorter than to other candidates. We have established an open public "MQ Challenge" (https://www.mqchallenge.org) to stimulate progress in the design of efficient algorithms to solve MQ problem, and thus test limit parameters guaranteeing security of MPKC..
15. Jian Weng, Yunlei Zhao, Robert H. Deng, Shengli Liu, Yanjiang Yang, Kouichi Sakurai, A note on the security of KHL scheme, Theoretical Computer Science, 10.1016/j.tcs.2015.07.051, 602, 1-6, 2015.10, A public key trace and revoke scheme combines the functionality of broadcast encryption with the capability of traitor tracing. In Asiacrypt 2003, Kim, Hwang and Lee proposed a public key trace and revoke scheme (referred to as KHL scheme), and gave the security proof to support that their scheme is z-resilient against adaptive chosen-ciphertext attacks, in which the adversary is allowed to adaptively issue decryption queries as well as adaptively corrupt up to z users. In the passed ten years, KHL scheme has been believed as one of the most efficient public key trace and revoke schemes with z-resilience against adaptive chosen-ciphertext attacks under the well-studied DDH assumption. However, in this paper, by giving a concrete attack, we indicate that KHL scheme is actually not secure against adaptive chosen-ciphertexts, even without corruption of any user. We then identify the flaws in the security proof for KHL-scheme, and discuss the consequences of the attack..
16. Mojtaba Alizadeh, Mazdak Zamani, Sabariah Baharun, Azizah Abdul Manaf, Kouichi Sakurai, Hiroki Anada, Hassan Keshavarz, Shehzad Ashraf Chaudhry, Muhammad Khurram Khan, Cryptanalysis and Improvement of "A Secure Password Authentication Mechanism for Seamless Handover in Proxy Mobile IPv6 Networks", PLOS ONE, 10.1371/journal.pone.0142716, 10, 11, 2015.11, Proxy Mobile IPv6 is a network-based localized mobility management protocol that supports mobility without mobile nodes' participation in mobility signaling. The details of user authentication procedure are not specified in this standard, hence, many authentication schemes have been proposed for this standard. In 2013, Chuang et al., proposed an authentication method for PMIPv6, called SPAM. However, Chuang et al.'s Scheme protects the network against some security attacks, but it is still vulnerable to impersonation and password guessing attacks. In addition, we discuss other security drawbacks such as lack of revocation procedure in case of loss or stolen device, and anonymity issues of the Chuang et al.'s scheme. We further propose an enhanced authentication method to mitigate the security issues of SPAM method and evaluate our scheme using BAN logic..
17. Satoshi Tanaka, Chen-Mou Cheng, Takanori Yasuda, Kouichi Sakurai, Parallelization of QUAD stream cipher using linear recurring sequences on graphics processing units, Proceedings - 2014 2nd International Symposium on Computing and Networking, CANDAR 2014, 10.1109/CANDAR.2014.85, 543-548, 2015.02, Proposed by Berbain, Gilbert, and Patarin in Euro crypt 2006, QUAD is a provably secure stream cipher. The speed of QUAD depends on the computational cost of evaluating quadratic polynomials over finite fields. For QUAD with m quadratic polynomials in n unknowns over GF (q), this requires O (mn2) GF (q) additions and multiplications. Petzoldt is able to reduce the evaluation cost to O (mn) GF (q) additions and multiplications by using linear recurring sequences to generate the coefficients. In this work, we parallelize and optimize his algorithm for running on Graphics Processing Unit (GPU). The result shows that our GPU implementation of the parallelized algorithm has achieved the best performance in the literature..
18. Nobuyuki Teraura, Kouichi Sakurai, Proposal of multi-value cell structure for high-density two-dimensional codes and evaluation of readability using smartphones, 2015 7th International Conference on New Technologies, Mobility and Security - Proceedings of NTMS 2015 Conference and Workshops, 10.1109/NTMS.2015.7266514, 2015.09, In the now-popular two-dimensional code, bits are expressed using white and two black colors in the cell, which forms the element. However, such codes do not have confidentiality. Since confidentiality may be needed according to the use, a large-capacity and high-density two-dimensional code with compatibility and confidentiality can be realized by adding a secrecy part in addition to the existing part. To enlarge capacity, it is necessary to form a cell using many bits, which requires a multicolor method. The read verification of the compatible area and the additional area was carried out using a smartphone, and the code was verified to confirm its practicality..
19. Chunhua Su, Jianying Zhou, Feng Bao, Tsuyoshi Takagi, Kouichi Sakurai, Collaborative agglomerative document clustering with limited information disclosure, SECURITY AND COMMUNICATION NETWORKS, 10.1002/sec.811, 7, 6, 964-978, 2014.06, Document clustering is a practical and powerful data mining technique to analyze large amount of documents and large sets of text or hypertext documents. However, it also brings the problem of sensitive information leaking in disregard of privacy, especially when it is executed in distributed environment. In this paper, we propose a cryptography-based framework to realize privacy-preserving document clustering among the users under the distributed environment; there are two parties, each having his private document database, want to collaboratively execute agglomerative document clustering without disclosing their private contents. We provide two implementations of such a framework, one is with more precision and stronger security but requires more computational resources. The other is a simplified version with less computational complexity and achieves higher processing speed. Additionally, we provide the security proofs and experimental analysis of precision and scalability of our proposal. Copyright (c) 2013 John Wiley & Sons, Ltd..
20. Yuto Nakano, Shinsaku Kiyomoto, Yutaka Miyake, Kouichi Sakurai, Comparison of Access Pattern Protection Schemes and Proposals for Efficient Implementation, IEICE TRANSACTIONS ON INFORMATION AND SYSTEMS, 10.1587/transinf.2013THP0007, E97D, 10, 2576-2585, 2014.10, Oblivious RAM (ORAM) schemes, the concept introduced by Goldreich and Ostrovsky, are very useful technique for protecting users' privacy when storing data in remote untrusted servers and running software on untrusted systems. However they are usually considered impractical due to their huge overhead. In order to reduce overhead, many improvements have been presented. Thanks to these improvements, ORAM schemes can be considered practical on cloud environment where users can expect huge storage and high computational power. Especially for private information retrieval (PIR), some literatures demonstrated they are usable. Also dedicated PIRs have been proposed and shown that they are usable in practice. Yet, they are still impractical for protecting software running on untrusted systems. We first survey recent researches on ORAM and PIR. Then, we present a practical software-based memory protection scheme applicable to several environments. The main feature of our scheme is that it records the history of accesses and uses the history to hide the access pattern. We also address implementing issues of ORAM and propose practical solutions for these issues..
21. Nobuyuki Teraura, Kouichi Sakurai, Evaluation of the identity and compatibility of multi-valued cells in two-dimensional codes using smartphones, Proceedings - IEEE 7th International Conference on Service-Oriented Computing and Applications, SOCA 2014, 10.1109/SOCA.2014.17, 252-259, 2014.12, Data is connected to the internet with a sensor for understanding the property of the thing for which a two-dimensional code was used. Two-dimensional codes can play the role of connecting cyberspace to physical space, and can play a significant role in the so-called Internet of Things. Moreover, the advancement of machine vision is progressing with machine-to-machine communication. On the other hand, there is also private information, such as personal information, that should not be known by others. Current two-dimensional codes have become ubiquitous and express the cell using two colors: white and black. The cell expresses white or black in one bit, and there is no confidentiality available. In response to this, we propose an addition to the existing part that can be read with conventional equipment. We propose a 'secrecy part' that cannot be read without a decryption key. Further, we propose a method for rendering these two-dimensional codes compatible with black-and-white codes. In order to generate the secrecy part, it is necessary to transform a cell into several bits. A multicolor method and a multiple-region method are used to transform the code into several bits. An evaluation of the multi-valued cells in the two-dimensional codes here proposed, with a read verification and compatibility along with the added secrecy part, was carried out using a smartphone with successful results..
22. Yuto Nakano, Kazuhide Fukushima, Shinsaku Kiyomoto, Tsukasa Ishiguro, Yutaka Miyake, Toshiaki Tanaka, Kouichi Sakurai, Fast Implementation of KCipher-2 for Software and Hardware, IEICE TRANSACTIONS ON INFORMATION AND SYSTEMS, 10.1587/transinf.E97.D.43, E97D, 1, 43-52, 2014.01, KCipher-2 is a word-oriented stream cipher and an ISOJEC 18033 standard. It is listed as a CRYPTREC cryptographic algorithm for Japanese governmental use. It consists of two feedback shift registers and a non-linear function. The size of each register in KCipher-2 is 32 bits and the non-linear function mainly applies 32-bit operations. Therefore, it can be efficiently implemented as software. SNOW-family stream ciphers are also word-oriented stream ciphers, and their high performance has already been demonstrated. We propose optimised implementations of KCipher-2 and compare their performance to that of the SNOW-family and other eSTREAM portfolios. The fastest algorithm is SNOW 2.0 and KCipher-2 is the second fastest despite the complicated irregular clocking mechanism. However, KCipher-2 is the fastest of the feasible algorithms, as SNOW 2.0 has been shown to have a security flaw. We also optimise the hardware implementation for the Virtex-5 field-programmable gate array (FPGA) and show two implementations. The first implementation is a rather straightforward optimisation and achieves 16,153 Mbps with 732 slices. In the second implementation, we duplicate the non-linear function using the structural advantage of KCipher-2 and we achieve 17,354 Mbps with 813 slices. Our implementation of KCipher-2 is around three times faster than those of the SNOW-family and efficiency, which is evaluated by "Throughput/Area (Mbps/slice)", is 3.6-times better than that of SNOW 2.0 and 8.5-times better than that of SNOW 3G. These syntheses are performed using Xilinx ISE version 12.4..
23. Takanori Yasuda, Tsuyoshi Takagi, Kouichi Sakurai, Security of Multivariate Signature Scheme Using Non-commutative Rings, IEICE TRANSACTIONS ON FUNDAMENTALS OF ELECTRONICS COMMUNICATIONS AND COMPUTER SCIENCES, 10.1587/transfun.E97.A.245, E97A, 1, 245-252, 2014.01, Multivariate Public Key Cryptosystems (MPKC) are candidates for post-quantum cryptography. Rainbow is a digital signature scheme in MPKC, whose signature generation and verification are relatively efficient. However, the security of MPKC depends on the difficulty in solving a system of multivariate polynomials, and the key length of MPKC becomes substantially large compared with that of RSA cryptosystems for the same level of security. The size of the secret and public keys in MPKC has been reduced in previous research. The NC-Rainbow is a signature scheme in MPKC, which was proposed in order to reduce the size of secret key of Rainbow. So far, several attacks against NC-Rainbow have been proposed. In this paper, we summarize attacks against NC-Rainbow, containing attacks against the original Rainbow, and analyze the total security of NC-Rainbow. Based on the cryptanalysis, we estimate the security parameter of NC-Rainbow at the several security level..
24. Jingyu Hua, Kouichi Sakurai, Botnet command and control based on Short Message Service and human mobility, Computer Networks, 10.1016/j.comnet.2012.06.007, 57, 2, 579-597, 2013.02, Many serious threats for PCs are spreading to the mobile environment. A mobile botnet, which is a collection of hijacked smartphones under the control of hackers, is one of them. With the quick development of the computing and communication abilities of smartphones, many command and control (C&
C) techniques in PC botnets can be easily reused in mobile botnets. However, some particular functions and characteristics of smartphones may provide botmasters with additional means to control their mobile botnets. This paper presents two special C&
C mechanisms that leverage Short Message Service and human mobility, respectively. The first one designs a SMS-based flooding algorithm to propagate commands. We theoretically prove that the uniform random graph is the optimal topology for this botnet, and demonstrate its high efficiency and stealth with various simulations. The second one utilizes Bluetooth to transmit botnet commands when hijacked smartphones encounter each other while in motion. We study its performance in a 100 m × 100 m square area with NS-2 simulations, and show that human-mobility characteristics facilitate the command propagation. Even if the infection rate is low, the command can still be effectively propagated provided that the mobility of devices is high. In the end, we propose effective defense strategies against these two special C&
C mechanisms. © 2012 Elsevier B.V. All rights reserved..
25. Satoshi Tanaka, Takashi Nishide, Kouichi Sakurai, Efficient implementation for QUAD stream cipher with GPUs, Computer Science and Information Systems, 10.2298/CSIS121102040T, 10, 2, 897-911, 2013.04, QUAD stream cipher uses multivariate polynomial systems. It has provable security based on the computational hardness assumption. More specifically, the security of QUAD depends on hardness of solving non-linear multivariate systems over a finite field, and it is known as an NP-complete problem. However, QUAD is slower than other stream ciphers, and an efficient implementation, which has a reduced computational cost, is required. In this paper, we propose an efficient implementation of computing multivariate polynomial systems for multivariate cryptography on GPU and evaluate efficiency of the proposal. GPU is considered to be a commodity parallel arithmetic unit. Moreover, we give an evaluation of our proposal. Our proposal parallelizes an algorithm of multivariate cryptography, and makes it efficient by optimizing the algorithm with GPU..
26. Yizhi Ren, Mingchu Li, Yang Xiang, Yongrui Cui, Kouichi Sakurai, Evolution of cooperation in reputation system by group-based scheme, Journal of Supercomputing, 10.1007/s11227-010-0498-8, 63, 1, 171-190, 2013.01, Reputation systems are very useful in large online communities in which users may frequently have the opportunity to interact with users with whom they have no prior experience. Recently, how to enhance the cooperative behaviors in the reputation system has become to one of the key open issues. Emerging schemes focused on developing efficient reward and punishment mechanisms or capturing the social or economic properties of participants. However, whether this kind of method can work widely or not has been hard to prove until now. Research in evolutionary game theory shows that group selection (or multilevel selection) can favor the cooperative behavior in the finite population. Furthermore, some recent works give fundamental conditions for the evolution of cooperation by group selection. In the paper, we extend the original group selection theory and propose a group-based scheme to enhance cooperation for online reputation systems. Related concepts are defined to capture the social structure and ties among participants in reputation system, e.g., group, assortativity, etc. Also, we use a Fermi distribution function to reflect the bounded rationality of participants and the existence of stochastic factors in evolutionary process. Extended simulations show that our scheme can enhance cooperation and improve the average performance of participants (e.g. payoff) in reputation system. © 2010 Springer Science+Business Media, LLC..
27. Dong Hao, Xiaojuan Liao, Avishek Adhikari, Kouichi Sakurai, Makoto Yokoo, A repeated game approach for analyzing the collusion on selective forwarding in multihop wireless networks, COMPUTER COMMUNICATIONS, 10.1016/j.comcom.2012.07.006, 35, 17, 2125-2137, 2012.10, In multihop wireless networks (MWNs), the selective forwarding attack is a special case of denial of service attack. In this attack, the malicious wireless nodes only forward a subset of the received packets, but drop the others. This attack becomes more severe if multiple attackers exist and collude together to disrupt the normal functioning of the secure protocols. By colluding, each attacker can even only drop a little packets, but the overall loss of the path will be high. However, most prior researches on selective forwarding attacks assume the attackers do not collude with each other. Furthermore, the previous works also lack of comprehensive security analysis. In this paper, by utilizing the game theoretic approach, we analyze the collusion in selective forwarding attacks. We first put forward a sub-route oriented punish and reward scheme, and propose an multi-attacker repeated colluding game. Then by static and dynamic analysis of this colluding attack game, we find the sub-game equilibriums which indicate the attackers' optimal attack strategies. Based on the analysis result, we establish a security policies for multihop wireless networks, to threaten and detect the malicious insider nodes which collude with each other to launch the selective forwarding attacks. (c) 2012 Elsevier B.V. All rights reserved..
28. Liang Zhao, Avishek Adhikari, Di Xiao, Kouichi Sakurai, On the security analysis of an image scrambling encryption of pixel bit and its improved scheme based on self-correlation encryption, COMMUNICATIONS IN NONLINEAR SCIENCE AND NUMERICAL SIMULATION, 10.1016/j.cnsns.2011.12.015, 17, 8, 3303-3327, 2012.08, An image scrambling encryption scheme for pixel bits was presented by Ye [Ye GD. Image scrambling encryption algorithm of pixel bit based on chaos map. Pattern Recognit Lett 2010;31:347-54], which can be seen as one kind of typical binary image scrambling encryption considering from the bit-plain of size M x (8N). However, recently, some defects existing in the original image encryption scheme, i.e., Ye's scheme, have been observed by Li and Lo [Li CQ, Lo KT. Optimal quantitative cryptanalysis of permutation-only multimedia ciphers against plaintext attacks. Signal Process 2011;91:949-54]. In the attack proposed by Li and Lo at least 3 + inverted right perpendicularlog(2)(MN)inverted left perpendicular plain images of size M x N are used to reveal the permutation matrix W = [w(i,k)] (i is an element of {1, 2, ... , M}; k is an element of {1, 2, ... , 8N}) which can be applied to recover the exact plain image. In the current paper, at first, one type of special plain image/cipher image is used to analyze the security weakness of the original image scrambling scheme under study. The final encryption vectors TM and TN or the decryption vectors TM' and TN' are revealed completely according to our attack. To demonstrate the performance of our attack, a quantified comparison is drawn between our attack and the attack proposed by Li and Lo. Compared with Li and Lo's attack, our attack is more efficient in the general conditions. In particular, when the sizes of images satisfy the condition M = N or M <= 8N, the number of the used plain images/cipher images is at most 9, which is sharply less than 3 + inverted right perpendicularlog(2)(MN)inverted left perpendicular when M and N are of large size. To overcome the weaknesses of the original scheme, in this paper, an improved image scrambling encryption scheme is proposed. In the improved scheme, the idea of the "self-correlation" method is used to resist the chosen-plaintext attack/known-plaintext attack. The corresponding simulations and analyses illustrate that the improved encryption method has good cryptographic properties, and can overcome the weakness of the original image encryption scheme. Finally, farther improvement is briefly presented for the future work. (C) 2011 Elsevier B.V. All rights reserved..
29. Ilsun You, Yoshiaki Hori, Kouichi Sakurai, Towards formal analysis of wireless LAN security with MIS protocol, International Journal of Ad Hoc and Ubiquitous Computing, 10.1504/IJAHUC.2011.038997, 7, 2, 112-120, 2011.03, In 2004, the MIS and MISAUTH protocols (shortly MISP) were proposed for secure and fast connection in Wireless LAN (WLAN). Since then, several studies were conducted to evaluate MISP. However, because of the lack of formal security analysis, the security measures provided by them cannot be trusted to be precise and reasonable. Motivated by this, we formally analyse MISP based on both BAN-logic and the Automated Validation of Internet Security Protocols and Applications (AVISPAS) tool. This analysis clearly shows that MISP suffers from weak Session Key (SK) while being vulnerable to Denial of Service (DoS) attack. We discuss these weaknesses and related attacks in detail, and also provide considerable comments for implementation of MISP. © 2011 Inderscience Enterprises Ltd..
30. Chunhua Su, Feng Bao, Jianying Zhou, Tsuyoshi Takagi, Kouichi Sakurai, Distributed Noise Generation for Density Estimation Based Clustering without Trusted Third Party, IEICE TRANSACTIONS ON FUNDAMENTALS OF ELECTRONICS COMMUNICATIONS AND COMPUTER SCIENCES, 10.1587/transfun.E92.A.1868, E92A, 8, 1868-1871, 2009.08, The rapid growth of the Internet provides people with tremendous opportunities for data collection, knowledge discovery and cooperative computation. However, it also brings the problem of sensitive information leakage. Both individuals and enterprises may suffer from the massive data collection and the information retrieval by distrusted parties. In this paper, we propose a privacy-preserving protocol for the distributed kernel density estimation-based clustering. Our scheme applies random data perturbation (RDP) technique and the verifiable secret sharing to solve the security problem of distributed kernel density estimation in [4] which assumed a mediate party to help in the computation,.
31. Chunhua Su, Feng Bao, Jianying Zhou, Tsuyoshi Takagi, Kouichi Sakurai, Security and Correctness Analysis on Privacy-Preserving k-Means Clustering Schemes, IEICE TRANSACTIONS ON FUNDAMENTALS OF ELECTRONICS COMMUNICATIONS AND COMPUTER SCIENCES, 10.1587/transfun.E92.A.1246, E92A, 4, 1246-1250, 2009.04, Due to the fast development of Internet and the related IT technologies, it becomes more and more easier to access a large amount of data. k-means clustering is a powerful and frequently used technique in data mining. Many research papers about privacy-preserving k-means clustering were published. In this paper, we analyze the existing privacy-preserving k-means clustering schemes based on the cryptographic techniques. We show those schemes will cause the privacy breach and cannot output the correct results due to the faults in the protocol construction. Furthermore, we analyze our proposal as an option to improve such problems but with intermediate information breach during the computation..
32. Kazuhide Fukushima, Shinsaku Kiyomoto, Toshiaki Tanaka, Kouichi Sakurai, Analysis of program obfuscation schemes with variable encoding technique, IEICE TRANSACTIONS ON FUNDAMENTALS OF ELECTRONICS COMMUNICATIONS AND COMPUTER SCIENCES, 10.1093/ietfec/e91-a.1.316, E91A, 1, 316-329, 2008.01, Program analysis techniques have improved steadily over the past several decades, and software obfuscation schemes have come to be used in many commercial programs. A software obfuscation scheme transforms an original program or a binary file into an obfuscated program that is more complicated and difficult to analyze, while preserving its functionality. However, the security of obfuscation schemes has not been properly evaluated. In this paper, we analyze obfuscation schemes in order to clarify the advantages of our scheme, the XOR-encoding scheme. First, we more clearly define five types of attack models that we defined previously, and define quantitative resistance to these attacks. Then, we compare the security, functionality and efficiency of three obfuscation schemes with encoding variables: (1) Sato et al.'s scheme with linear transformation, (2) our previous scheme with affine transformation, and (3) the XOR-encoding scheme. We show that the XOR-encoding scheme is superior with regard to the following two points: (1) the XOR-encoding scheme is more secure against a data-dependency attack and a brute force attack than our previous scheme, and is as secure against an information-collecting attack and an inverse transformation attack as our previous scheme, (2) the XOR-encoding scheme does not restrict the calculable ranges of programs and the loss of efficiency is less than in our previous scheme..
33. Kenji Imamoto, Kouichi Sakurai, Design and analysis of Diffie-Hellman-based key exchange using one-time ID by SVO logic, Electronic Notes in Theoretical Computer Science, 10.1016/j.entcs.2005.06.003, 135, 1, 79-94, 2005.07, Authenticated key exchange protocols have been developed to establish secure channel on the Internet. In this paper, we consider following attacks against an authenticated key exchange using shared secret: eavesdropping, DoS attack, replay attack, and impersonation. Besides prevention from all these attacks, efficiency is also important. In this paper, we propose a three-party authenticated key exchange protocol based on Diffie-Hellman key exchange with one-time ID, which is a user's extraordinary identity used only once [K. Imamoto, K. Sakurai, Notes on Dynamic Information Management for Authenticated Key Exchange, ISEC, March 2003
H. Krawczyk, The IKE-SIGMA Protocol, Internet Draft, Nov 2001. http://www.ee.technion.ac.il/~hugo/draft-krawczyk-ipsec-ike- sigma-00.txt]. Moreover, we analyze our proposal by SVO Logic, which is one of formal methods to analyze cryptographic protocols [P. Syverson and P. C. van Oorschot. A Unified Cryptographic Protocol Logic. NRL CHAOS Report, 5540-227, 1996
P. Syverson and I. Cervesato. The Logic of Authentication Protocols. FOSAD'00, LNCS2171, pp.63-137, 2001], and show what assumptions are needed. © 2005 Published by Elseveir B.V..
34. Keiichi Iwamura, Kouichi Sakurai, Hideki Imai, A secure digital watermark system for secondary distribution, Electronics and Communications in Japan, Part III: Fundamental Electronic Science (English translation of Denshi Tsushin Gakkai Ronbunshi), 10.1002/ecjc.1151, 86, 6, 76-85, 2003.06, Conventional digital watermark systems assume that the distributor (server) is a completely reliable organization. If the server is not a reliable organization, in a conventional system it is possible that suspicion may fall on a user who is not illegally distributing. Several methods have been proposed to handle this problem. In these methods, however, the system is essentially composed of two kinds of entities: the agent and the users. There is no discussion of a system composed of three entities - authors, agent, and users - where secondary distribution takes place from the author to an agent and then to the users. This paper proposes a digital watermark system that can prevent illegal conduct in a secondary distribution system composed of three types of entities - authors, agent, and users..
35. Kouichi Sakurai, Practical proofs of knowledge without relying on theoretical proofs of membership on languages, Theoretical Computer Science, 10.1016/S0304-3975(96)00277-0, 181, 2, 317-335, 1997.07, Formulations and properties of proving possession of knowledge in interactive protocols are investigated. A four-move protocol for quadratic residuosity is proposed and a new notion of practical soundness is introduced based on its application to a cryptographic identification scheme. The role of cryptographic assumptions in arguments (i.e., computationally convincing proofs) of knowledge is also explored..
36. Akio Yanbe, Kouichi Sakurai, A short certificate of the number of universal optimal strategies for stopping simple stochastic games, Information Processing Letters, 10.1016/0020-0190(95)00181-6, 57, 1, 17-24, 1996.01.
37. Ishak Meraouche, Sabyasachi Dutta, Kouichi Sakurai, 3-Party Adversarial Cryptography, Lecture Notes on Data Engineering and Communications Technologies, 10.1007/978-3-030-39746-3_27, 247-258, 2020.01, The domain of Artificial Intelligence (AI) has seen an outstanding growth during the last two decades. It has proven its efficiency in handling complex domains including speech recognition, image recognition and many more. One interesting and evolving branch that was put forward years ago but have seen a good growth only during the past few years is encryption using AI. After Google announced that it has succeeded teaching neural networks encryption in the presence of Eavesdroppers, research in this particular area has seen a rapid spread of interest among different researchers all over the world to develop new Neural Networks capable of operating different cryptographic tasks. In this paper, we take initial steps to achieve secure communication among more than two parties using neural network based encryption. We forward the idea of two party symmetric encryption scheme of Google to a multi party Encryption scheme. In this paper we will focus on a 3-Party case..
38. Haibo Zhang, Kouichi Sakurai, Blockchain for IoT-Based Digital Supply Chain
A Survey, Lecture Notes on Data Engineering and Communications Technologies, 10.1007/978-3-030-39746-3_57, 564-573, 2020.01, This exploratory investigation aims to discuss current network environment of digital supply chain system and security issues, especially from the Internet world, of digital supply chain management system with applying some advanced information technologies, such as Internet of Things and blockchain, for improving various system performance and properties. This paper introduces the general histories and backgrounds, in terms of information science, of the supply chain and relevant technologies which have been applied or are potential to be applied on supply chain with purpose of lowering cost, facilitating its security and convenience. It provides a comprehensive review of current relative research work and industrial cases from several famous companies. It also illustrates the IoT enablement and security issues of current digital supply chain system, and existing blockchain’s role in this kind of digital system. Finally, this paper concludes several potential or existing security issues and challenges which supply chain management is facing..
39. Daiji Hara, Kouichi Sakurai, Yasuo Musashi, Classification of Malicious Domains by Their LIFETIME, Lecture Notes on Data Engineering and Communications Technologies, 10.1007/978-3-030-39746-3_35, 334-341, 2020.01, In this study, we look for malicious domains in the logs of the primary DNS server of Kumamoto University using a malicious domain check tool (Virus Total), We then classify them according to their LIFETIME (LT) and investigate their main attack applications. The following results were obtained from the experiment: (1) Ransomware, phishing, and DDoS attacks were the 3 most frequent attacks. (2) We obtained two sets of LIFETIME by plotting the number of malicious domains according to their frequency (3) The frequency distribution obtained on ransomware, phishing, and DDoS attacks show that the LT distribution of ransomware and phishing is similar, however, the frequency of DDoS attacks is shorter. (4) From these results, we learn that the attack method can be determined by measuring the LT. The LT shows to be a good parameter to be used with machine learning to detect malicious domain names..
40. Yan Naung Soe, Yaokai Feng, Paulus Insap Santosa, Rudy Hartanto, Kouichi Sakurai, Towards a lightweight detection system for cyber attacks in the IoT environment using corresponding features, Electronics (Switzerland), 10.3390/electronics9010144, 9, 1, 2020.01, The application of a large number of Internet of Things (IoT) devices makes our life more convenient and industries more efficient. However, it also makes cyber-attacks much easier to occur because so many IoT devices are deployed and most of them do not have enough resources (i.e., computation and storage capacity) to carry out ordinary intrusion detection systems (IDSs). In this study, a lightweight machine learning-based IDS using a new feature selection algorithm is designed and implemented on Raspberry Pi, and its performance is verified using a public dataset collected from an IoT environment. To make the system lightweight, we propose a new algorithm for feature selection, called the correlated-set thresholding on gain-ratio (CST-GR) algorithm, to select really necessary features. Because the feature selection is conducted on three specific kinds of cyber-attacks, the number of selected features can be significantly reduced, which makes the classifiers very small and fast. Thus, our detection system is lightweight enough to be implemented and carried out in a Raspberry Pi system. More importantly, as the really necessary features corresponding to each kind of attack are exploited, good detection performance can be expected. The performance of our proposal is examined in detail with different machine learning algorithms, in order to learn which of them is the best option for our system. The experiment results indicate that the new feature selection algorithm can select only very few features for each kind of attack. Thus, the detection system is lightweight enough to be implemented in the Raspberry Pi environment with almost no sacrifice on detection performance..
41. Satya Lokam, Sushmita Ruj, Kouichi Sakurai, BCC'19 chairs' welcome, 3rd ACM Workshop on Blockchains, Cryptocurrencies, and Contracts, BCC 2019, held in conjunction with the 14th ACM Asia Conference on Computer and Communications Security, AsiaCCS 2019 BCC 2019 - Proceedings of the 3rd ACM Workshop on Blockchains, Cryptocurrencies and Contracts, co-located with AsiaCCS 2019, III, 2019.07.
42. Wai Kyi Kyi Oo, Hiroshi Koide, Danilo Vasconcellos Vargas, Kouichi Sakurai, A new design for evaluating moving target defense system, 6th International Symposium on Computing and Networking Workshops, CANDARW 2018 Proceedings - 2018 6th International Symposium on Computing and Networking Workshops, CANDARW 2018, 10.1109/CANDARW.2018.00111, 561-563, 2018.12, Moving Target Defense (MTD) concept has been a feasible idea for reducing the possibility of attack happening through alternation attack surfaces or diversification the attribute or parameters of a protected system. As a result of applying MTD techniques to the system, an attacker would have more difficulties in exploiting a vulnerabilities of the target system. This study proposes an evaluation method of MTD systems combined with several different MTD techniques. The proposed method is a primary step in designing an evaluation model for the effectiveness of MTD. The main goal is to estimate the attack success ratio on the MTD systems mitigating from threats of executable binary file or malware injection. With the proposed evaluation method, we expect to prove that the MTD technology can enhance the security of a web server, and can be applied in a real-world information system. As our preliminary work done, we set up a prototype framework to validate the proposed work in a pseudo-experimental environment..
43. Ryousuke Komiya, Yaokai Feng, Kouichi Sakurai, Detecting distributed cyber attacks in SDN based on automatic thresholding, 6th International Symposium on Computing and Networking Workshops, CANDARW 2018 Proceedings - 2018 6th International Symposium on Computing and Networking Workshops, CANDARW 2018, 10.1109/CANDARW.2018.00083, 417-423, 2018.12, Distributed Cyber Attack launched from many hosts simultaneously has become one of the most sophisticated and the most dangerous attacks in the cyber world including the traditional Internet and the SDN (Software Defined Networking) environments. As a kind of centralized network environment, the SDN has been greatly developed and popularized in recent years, especially in cloud systems. Thus, how to efficiently detect distributed attacks in SDN environments has attracted great attentions in academia and industry and various researches have been done to counter such attacks. The latest related researches made attempts to exploit the information of the PacketIn packets collected in the SDN controller and those methods proved efficient for detecting distributed cyber attacks in SDN environments. However, such methods adopted a threshold for distinguishing between attacks and normal situations. The threshold must be properly determined manually in advance, which is not easy in many applications even for experts. In this study, we try to automatically extract a proper threshold from the historical data of the monitored SDN environment so that the difficult parameter-tuning (determination of the threshold) process can be removed. In addition, because the extracted threshold can well reflect the actual situations of the monitored environment, a better detection performance than the existing approaches can be expected. The detection performance of our proposal is also tested using real traffic data..
44. Jiawei Su, Danilo Vasconcellos Vargas, Kouichi Sakurai, Empirical evaluation on robustness of deep convolutional neural networks activation functions against adversarial perturbation, 6th International Symposium on Computing and Networking Workshops, CANDARW 2018 Proceedings - 2018 6th International Symposium on Computing and Networking Workshops, CANDARW 2018, 10.1109/CANDARW.2018.00049, 223-227, 2018.12, Recent research has shown that deep convolutional neural networks (DCNN) are vulnerable to several different types of attacks while the reasons of such vulnerability are still under investigation. For instance, the adversarial perturbations can conduct a slight change on a natural image to make the target DCNN make the wrong recognition, while the reasons that DCNN is sensitive to such small modification are divergent from one research to another. In this paper, we evaluate the robustness of two commonly used activation functions of DCNN, namely the sigmoid and ReLu, against the recently proposed low-dimensional one-pixel attack. We show that the choosing of activation functions can be an important factor that influences the robustness of DCNN. The results show that comparing with sigmoid, the ReLu non-linearity is more vulnerable which allows the low dimensional one-pixel attack exploit much higher success rate and confidence of launching the attack. The results give insights on designing new activation functions to enhance the security of DCNN..
45. Yuetong Zhu, Danilo Vasconcellos Vargas, Kouichi Sakurai, Neural cryptography based on the topology evolving neural networks, 6th International Symposium on Computing and Networking Workshops, CANDARW 2018 Proceedings - 2018 6th International Symposium on Computing and Networking Workshops, CANDARW 2018, 10.1109/CANDARW.2018.00091, 472-478, 2018.12, Modern cryptographic schemes is developed based on the mathematical theory. Recently works show a new direction about cryptography based on the neural networks. Instead of learning a specific algorithm, a cryptographic scheme is generated automatically. While one kind of neural network is used to achieve the scheme, the idea of the neural cryptography can be realized by other neural network architecture is unknown. In this paper, we make use of this property to create neural cryptography scheme on a new topology evolving neural network architecture called Spectrum-diverse unified neuroevolution architecture. First, experiments are conducted to verify that Spectrum-diverse unified neuroevolution architecture is able to achieve automatic encryption and decryption. Subsequently, we do experiments to achieve the neural symmetric cryptosystem by using adversarial training..
46. Asoke K. Talukder, Manish Chaitanya, David Arnold, Kouichi Sakurai, Proof of disease
A blockchain consensus protocol for accurate medical decisions and reducing the disease burden, 4th IEEE SmartWorld, 15th IEEE International Conference on Ubiquitous Intelligence and Computing, Advanced and Trusted Computing, Scalable Computing and Communications, Cloud and Big Data Computing, Internet of People and Smart City Innovations, SmartWorld/UIC/ATC/ScalCom/CBDCom/IoP/SCI 2018 Proceedings - 2018 IEEE SmartWorld, Ubiquitous Intelligence and Computing, Advanced and Trusted Computing, Scalable Computing and Communications, Cloud and Big Data Computing, Internet of People and Smart City Innovations, SmartWorld/UIC/ATC/ScalCom/CBDCom/IoP/SCI 2018, 10.1109/SmartWorld.2018.00079, 257-262, 2018.12, Studies suggest that a significant proportion of the diagnosis in non-communicable diseases (NCD) is erroneous, unwanted, or unnecessary. To reduce the disease burden and improve public health, algorithmic support is essential. To realize this, health data must be computer understandable, secured, ubiquitous, and interoperable. Medical and disease data entered into computers are unstructured natural language texts with medical jargons which a computer normally cannot understand. EMR (Electronic Medical Records) are data silos in the hospital and do not interoperate. In this paper we present Ethereum based future ready Proof of Disease (PoD) consensus protocol with a computer understandable single instance of truth. It will solve many challenges that electronic health records (EHR) or health information exchange (HIE) have failed to address. This medical system will help achieve all the complex needs of P6 (Participatory, Personalized, Proactive, Preventive, Predictive and Precision) medicine and finally reduce the disease burden..
47. Yuki Nishida, Kosuke Kaneko, Subodh Sharma, Kouichi Sakurai, Suppressing chain size of blockchain-based information sharing for swarm robotic systems, 6th International Symposium on Computing and Networking Workshops, CANDARW 2018 Proceedings - 2018 6th International Symposium on Computing and Networking Workshops, CANDARW 2018, 10.1109/CANDARW.2018.00102, 524-528, 2018.12, Swarm robotics is a research field in which a group of autonomous robots execute tasks through cooperative works. Sharing information among robots is a central function for an optimal performance of the system. Given that the swarm network structure constantly changes when robots move, it becomes difficult to guarantee on information sharing by all swarm members. We, in this work, propose an approach for information sharing on swarm robotic systems by using Blockchain technology. A function of distributed ledger in Blockchain technology has possibility to solve the information sharing problem and to easily synchronize their state. However, because Blockchain persistently keeps past transactions, the increase of its chain size is one of the serious issues to manage Blockchain technology. In this paper, we introduce a methodology to share information among autonomous robots and demonstrate through experiments that how the differences in data size recorded in the blockchain affect the chain size. As a result, compared with our previous approach, we succeeded in suppressing increase in chain size by using the proposal approach; it was reduced the amount of increase in chain size about 73.0% when each node repeatedly shared about 2.8KB image data by 100 times..
48. Yao Xu, Hiroshi Koide, Danilo Vasconcellos Vargas, Kouichi Sakurai, Tracing MIRAI malware in networked system, 6th International Symposium on Computing and Networking Workshops, CANDARW 2018 Proceedings - 2018 6th International Symposium on Computing and Networking Workshops, CANDARW 2018, 10.1109/CANDARW.2018.00104, 534-538, 2018.12, In 2021, it is anticipated that there will be approximately 30 billion Internet of Things (IoT) devices. The tremendous aggregate value of the IoT makes it a tempting and lucrative target for cyber criminals. The breakout of Mirai malware, which compromises poorly secured IoT devices with factory-default username and passphrase to launch Distributed Denial of Service (DDoS) attacks, has raised broad awareness towards the need for increased IoT security. To better defend against Mirai infection and spread, it is critical to know how the malware operates as the first step. In this paper, we give a combined static and dynamic analysis of Mirai, basing on the results of which, we introduce the application of Threat Tracer. Threat tracer is an information system simulator initially developed to help design a system robust against Advanced Persistent Attacks(APT). It offers an intuitive track on how a cyber threat behaves in a complicated networked system. The feedback simultaneously contributes to revealing vulnerabilities of a system. Our work focuses on the replication of Mirai Malware's operating processes in Threat Tracer simulation. By achieving doing so, we believe it could offer a comprehensible description of how Mirai acts. Also, considering the continuous emergence of Mirai variants, the simulation serves as a predictor on upcoming threats' behavior patterns..
49. Yaokai Feng, Hitoshi Akiyama, Liang Lu, Kouichi Sakurai, Feature selection for machine learning-based early detection of distributed cyber attacks, 16th IEEE International Conference on Dependable, Autonomic and Secure Computing, IEEE 16th International Conference on Pervasive Intelligence and Computing, IEEE 4th International Conference on Big Data Intelligence and Computing and IEEE 3rd Cyber Science and Technology Congress, DASC-PICom-DataCom-CyberSciTec 2018 Proceedings - IEEE 16th International Conference on Dependable, Autonomic and Secure Computing, IEEE 16th International Conference on Pervasive Intelligence and Computing, IEEE 4th International Conference on Big Data Intelligence and Computing and IEEE 3rd Cyber Science and Technology Congress, DASC-PICom-DataCom-CyberSciTec 2018, 10.1109/DASC/PiCom/DataCom/CyberSciTec.2018.00040, 181-186, 2018.10, It is well known that distributed cyber attacks simultaneously launched from many hosts have caused the most serious problems in recent years including problems of privacy leakage and denial of services. Thus, how to detect those attacks at early stage has become an important and urgent topic in the cyber security community. For this purpose, recognizing C&C (Command & Control) communication between compromised bots and the C&C server becomes a crucially important issue, because C&C communication is in the preparation phase of distributed attacks. Although attack detection based on signature has been practically applied since long ago, it is well-known that it cannot efficiently deal with new kinds of attacks. In recent years, ML(Machine learning)-based detection methods have been studied widely. In those methods, feature selection is obviously very important to the detection performance. We once utilized up to 55 features to pick out C&C traffic in order to accomplish early detection of DDoS attacks. In this work, we try to answer the question that 'Are all of those features really necessary?' We mainly investigate how the detection performance moves as the features are removed from those having lowest importance and we try to make it clear that what features should be payed attention for early detection of distributed attacks. We use honeypot data collected during the period from 2008 to 2013. SVM(Support Vector Machine) and PCA(Principal Component Analysis) are utilized for feature selection and SVM and RF(Random Forest) are for building the classifier. We find that the detection performance is generally getting better if more features are utilized. However, after the number of features has reached around 40, the detection performance will not change much even more features are used. It is also verified that, in some specific cases, more features do not always means a better detection performance. We also discuss 10 important features which have the biggest influence on classification..
50. Satya Lokam, Sushmita Ruj, Kouichi Sakurai, BCC'18 chairs' welcome, 2nd ACM Workshop on Blockchains, Cryptocurrencies, and Contracts, BCC 2018 BCC 2018 - Proceedings of the 2nd ACM Workshop on Blockchains, Cryptocurrencies, and Contracts, Co-located with ASIA CCS 2018, iii, 2018.05.
51. Mosarrat Jahan, Mohsen Rezvani, Qianrui Zhao, Partha Sarathi Roy, Kouichi Sakurai, Aruna Seneviratne, Sanjay Jha, Light Weight Write Mechanism for Cloud Data, IEEE Transactions on Parallel and Distributed Systems, 10.1109/TPDS.2017.2782253, 29, 5, 1131-1146, 2018.05, Outsourcing data to the cloud for computation and storage has been on the rise in recent years. In this paper we investigate the problem of supporting write operation on the outsourced data for clients using mobile devices. We consider the Ciphertext-Policy Attribute-based Encryption (CP-ABE) scheme as it is well suited to support access control in outsourced cloud environments. One shortcoming of CP-ABE is that users can modify the access policy specified by the data owner if write operations are incorporated in the scheme. We propose a protocol for collaborative processing of outsourced data that enables the authorized users to perform write operation without being able to alter the access policy specified by the data owner. Our scheme is accompanied with a light weight signature scheme and simple, inexpensive user revocation mechanism to make it suitable for processing on resource-constrained mobile devices. The implementation and detailed performance analysis of the scheme indicate the suitability of the proposed scheme for real mobile applications. Moreover, the security analysis demonstrates that the security properties of the system are not compromised..
52. Shiqian Yu, Danilo Vasconcellos Vargas, Kouichi Sakurai, Effectively Protect Your Privacy
Enabling Flexible Privacy Control on Web Tracking, 5th International Symposium on Computing and Networking, CANDAR 2017 Proceedings - 2017 5th International Symposium on Computing and Networking, CANDAR 2017, 10.1109/CANDAR.2017.26, 533-536, 2018.04, Third-party tracking, which can collect the users' privacy when users are surfing the Internet, has garnered much attention. Nowadays tracker-blocking tools often use a ruleset based on the domains and elements that need to be blocked. This results in blocking all access tracking, even though the website shows no sign about tracking users' privacy. And what's more, although the tracker-blocking tools try their best to block all the third-party tracking, not all the users dislike the advertisement. Some of them think if their privacy is fine, it's all right to accept advertisements. In this paper, we present a novel framework by using Word2Vec to block third-party tracking. Our goal is to create more flexible and well-developed ruleset that can help users to protect their privacy according to their needs. Instead of blocking all access tracking, we decide to pay more attention to the websites that have a strong probability to collect the users' privacy. We use Word2Vec to classify the websites, and our results show that after using our framework, the error rate drops from 71% to 24%. We believe it brings the new blood into the field of web privacy by providing not only the new third-party tracking tool but also a novel way of thinking about how to block the third-party tracking..
53. Xiang You, Yaokai Feng, Kouichi Sakurai, Packet in Message Based DDoS Attack Detection in SDN Network Using OpenFlow, 5th International Symposium on Computing and Networking, CANDAR 2017 Proceedings - 2017 5th International Symposium on Computing and Networking, CANDAR 2017, 10.1109/CANDAR.2017.93, 2018-January, 522-528, 2018.04, Using the OpenFlow protocol, the virtual network technology SDN (Software Defined Network) is now widely used. In recent years, the number of DDoS attacks has been increasing year by year. To detect DDoS attacks in SDN, data recorded in the flow table in OpenFlow switch is analyzed and various detection methods are submitted. However, SDN centrally manages communication within the network, when detecting DDoS (Distributed Denial of Service) attacks. This creates a heavy processing load, and the processing load of the OpenFlow controller must be considered. In this paper, in order to reduce the processing load of the controller, we do not collect data of the flow table, extract three features from the Packet In message for communication between the controller and the switch, and perform real-time attack detection. Furthermore, to avoid stringent detection time intervals, triggers will be added before detection to realize light and dynamic DDoS attacks detection..
54. Jiawei Su, Danilo Vasconcellos Vargas, Kouichi Sakurai, Attacking convolutional neural network using differential evolution, IPSJ Transactions on Computer Vision and Applications, 10.1186/s41074-019-0053-3, 11, 1, 2019.02, The output of convolutional neural networks (CNNs) has been shown to be discontinuous which can make the CNN image classifier vulnerable to small well-tuned artificial perturbation. That is, images modified by conducting such alteration (i.e., adversarial perturbation) that make little difference to the human eyes can completely change the CNN classification results. In this paper, we propose a practical attack using differential evolution (DE) for generating effective adversarial perturbations. We comprehensively evaluate the effectiveness of different types of DEs for conducting the attack on different network structures. The proposed method only modifies five pixels (i.e., few-pixel attack), and it is a black-box attack which only requires the miracle feedback of the target CNN systems. The results show that under strict constraints which simultaneously control the number of pixels changed and overall perturbation strength, attacking can achieve 72.29%, 72.30%, and 61.28% non-targeted attack success rates, with 88.68%, 83.63%, and 73.07% confidence on average, on three common types of CNNs. The attack only requires modifying five pixels with 20.44, 14.28, and 22.98 pixel value distortion. Thus, we show that current deep neural networks are also vulnerable to such simpler black-box attacks even under very limited attack conditions..
55. Hiroaki Anada, Tomohiro Matsushima, Chunhua Su, Weizhi Meng, Junpei Kawamoto, Samiran Bag, Kouichi Sakurai, Analysis of variance of graph-clique mining for scalable proof of work, 14th International Conference on Information Security and Cryptology, Inscrypt 2018 Information Security and Cryptology - 14th International Conference, Inscrypt 2018, Revised Selected Papers, 10.1007/978-3-030-14234-6_6, 101-114, 2019.01, Recently, Bitcoin is becoming one of the most popular decentralized cryptographic currency technologies, and Bitcoin mining is a process of adding transaction records to Bitcoin’s public ledger of past transactions or blockchain. To obtain a bitcoin, the mining process involves compiling recent transactions into blocks and trying to solve a computationally difficult puzzle, e.g., proof of work puzzle. A proof of work allows miners the ability to quantify how much work a given proof contains. Basically, the required time for mining is decided in advance, but problems will occur if the value is large for dispersion. In this paper, we first accept that the required time between consecutive blocks follows the exponential distribution. That is, the variance is stable as long as the expected time is fixed. Then, we focus on the graph clique mining technique proposed by the literature, like Tromp (BITCOIN 2015) and Bag-Ruj-Sakurai (Inscrypt 2015), which is based on a computational difficulty problem of searching cliques of undirected graphs, where a clique is a subset of vertices. In particular, when the clique size is two, graph clique mining can be used to gain Bitcoins. The previous work also claimed that if the clique size is parameterized and increased, even if the expected time is fixed, the variance would not be stable. However, no qualitative or quantitative results were given to support their claim. Motivated by this issue, in this work, we propose a simple search algorithm for graph cliques mining, and perform a small scale evaluation on Bitcoin and Graph cliques’s solo mining to investigate the variance issue..
56. Wai Kyi Kyi Oo, Hiroshi Koide, Danilo Vasconcellos Vargas, Kouichi Sakurai, A new design for evaluating moving target defense system, 6th International Symposium on Computing and Networking Workshops, CANDARW 2018 Proceedings - 2018 6th International Symposium on Computing and Networking Workshops, CANDARW 2018, 10.1109/CANDARW.2018.00111, 561-563, 2018.12, Moving Target Defense (MTD) concept has been a feasible idea for reducing the possibility of attack happening through alternation attack surfaces or diversification the attribute or parameters of a protected system. As a result of applying MTD techniques to the system, an attacker would have more difficulties in exploiting a vulnerabilities of the target system. This study proposes an evaluation method of MTD systems combined with several different MTD techniques. The proposed method is a primary step in designing an evaluation model for the effectiveness of MTD. The main goal is to estimate the attack success ratio on the MTD systems mitigating from threats of executable binary file or malware injection. With the proposed evaluation method, we expect to prove that the MTD technology can enhance the security of a web server, and can be applied in a real-world information system. As our preliminary work done, we set up a prototype framework to validate the proposed work in a pseudo-experimental environment..
57. Ryousuke Komiya, Yaokai Feng, Kouichi Sakurai, Detecting distributed cyber attacks in SDN based on automatic thresholding, 6th International Symposium on Computing and Networking Workshops, CANDARW 2018 Proceedings - 2018 6th International Symposium on Computing and Networking Workshops, CANDARW 2018, 10.1109/CANDARW.2018.00083, 417-423, 2018.12, Distributed Cyber Attack launched from many hosts simultaneously has become one of the most sophisticated and the most dangerous attacks in the cyber world including the traditional Internet and the SDN (Software Defined Networking) environments. As a kind of centralized network environment, the SDN has been greatly developed and popularized in recent years, especially in cloud systems. Thus, how to efficiently detect distributed attacks in SDN environments has attracted great attentions in academia and industry and various researches have been done to counter such attacks. The latest related researches made attempts to exploit the information of the PacketIn packets collected in the SDN controller and those methods proved efficient for detecting distributed cyber attacks in SDN environments. However, such methods adopted a threshold for distinguishing between attacks and normal situations. The threshold must be properly determined manually in advance, which is not easy in many applications even for experts. In this study, we try to automatically extract a proper threshold from the historical data of the monitored SDN environment so that the difficult parameter-tuning (determination of the threshold) process can be removed. In addition, because the extracted threshold can well reflect the actual situations of the monitored environment, a better detection performance than the existing approaches can be expected. The detection performance of our proposal is also tested using real traffic data..
58. Jiawei Su, Danilo Vasconcellos Vargas, Kouichi Sakurai, Empirical evaluation on robustness of deep convolutional neural networks activation functions against adversarial perturbation, 6th International Symposium on Computing and Networking Workshops, CANDARW 2018 Proceedings - 2018 6th International Symposium on Computing and Networking Workshops, CANDARW 2018, 10.1109/CANDARW.2018.00049, 223-227, 2018.12, Recent research has shown that deep convolutional neural networks (DCNN) are vulnerable to several different types of attacks while the reasons of such vulnerability are still under investigation. For instance, the adversarial perturbations can conduct a slight change on a natural image to make the target DCNN make the wrong recognition, while the reasons that DCNN is sensitive to such small modification are divergent from one research to another. In this paper, we evaluate the robustness of two commonly used activation functions of DCNN, namely the sigmoid and ReLu, against the recently proposed low-dimensional one-pixel attack. We show that the choosing of activation functions can be an important factor that influences the robustness of DCNN. The results show that comparing with sigmoid, the ReLu non-linearity is more vulnerable which allows the low dimensional one-pixel attack exploit much higher success rate and confidence of launching the attack. The results give insights on designing new activation functions to enhance the security of DCNN..
59. Yuetong Zhu, Danilo Vasconcellos Vargas, Kouichi Sakurai, Neural cryptography based on the topology evolving neural networks, 6th International Symposium on Computing and Networking Workshops, CANDARW 2018 Proceedings - 2018 6th International Symposium on Computing and Networking Workshops, CANDARW 2018, 10.1109/CANDARW.2018.00091, 472-478, 2018.12, Modern cryptographic schemes is developed based on the mathematical theory. Recently works show a new direction about cryptography based on the neural networks. Instead of learning a specific algorithm, a cryptographic scheme is generated automatically. While one kind of neural network is used to achieve the scheme, the idea of the neural cryptography can be realized by other neural network architecture is unknown. In this paper, we make use of this property to create neural cryptography scheme on a new topology evolving neural network architecture called Spectrum-diverse unified neuroevolution architecture. First, experiments are conducted to verify that Spectrum-diverse unified neuroevolution architecture is able to achieve automatic encryption and decryption. Subsequently, we do experiments to achieve the neural symmetric cryptosystem by using adversarial training..
60. Asoke K. Talukder, Manish Chaitanya, David Arnold, Kouichi Sakurai, Proof of disease
A blockchain consensus protocol for accurate medical decisions and reducing the disease burden, 4th IEEE SmartWorld, 15th IEEE International Conference on Ubiquitous Intelligence and Computing, Advanced and Trusted Computing, Scalable Computing and Communications, Cloud and Big Data Computing, Internet of People and Smart City Innovations, SmartWorld/UIC/ATC/ScalCom/CBDCom/IoP/SCI 2018 Proceedings - 2018 IEEE SmartWorld, Ubiquitous Intelligence and Computing, Advanced and Trusted Computing, Scalable Computing and Communications, Cloud and Big Data Computing, Internet of People and Smart City Innovations, SmartWorld/UIC/ATC/ScalCom/CBDCom/IoP/SCI 2018, 10.1109/SmartWorld.2018.00079, 257-262, 2018.12, Studies suggest that a significant proportion of the diagnosis in non-communicable diseases (NCD) is erroneous, unwanted, or unnecessary. To reduce the disease burden and improve public health, algorithmic support is essential. To realize this, health data must be computer understandable, secured, ubiquitous, and interoperable. Medical and disease data entered into computers are unstructured natural language texts with medical jargons which a computer normally cannot understand. EMR (Electronic Medical Records) are data silos in the hospital and do not interoperate. In this paper we present Ethereum based future ready Proof of Disease (PoD) consensus protocol with a computer understandable single instance of truth. It will solve many challenges that electronic health records (EHR) or health information exchange (HIE) have failed to address. This medical system will help achieve all the complex needs of P6 (Participatory, Personalized, Proactive, Preventive, Predictive and Precision) medicine and finally reduce the disease burden..
61. Yuki Nishida, Kosuke Kaneko, Subodh Sharma, Kouichi Sakurai, Suppressing chain size of blockchain-based information sharing for swarm robotic systems, 6th International Symposium on Computing and Networking Workshops, CANDARW 2018 Proceedings - 2018 6th International Symposium on Computing and Networking Workshops, CANDARW 2018, 10.1109/CANDARW.2018.00102, 524-528, 2018.12, Swarm robotics is a research field in which a group of autonomous robots execute tasks through cooperative works. Sharing information among robots is a central function for an optimal performance of the system. Given that the swarm network structure constantly changes when robots move, it becomes difficult to guarantee on information sharing by all swarm members. We, in this work, propose an approach for information sharing on swarm robotic systems by using Blockchain technology. A function of distributed ledger in Blockchain technology has possibility to solve the information sharing problem and to easily synchronize their state. However, because Blockchain persistently keeps past transactions, the increase of its chain size is one of the serious issues to manage Blockchain technology. In this paper, we introduce a methodology to share information among autonomous robots and demonstrate through experiments that how the differences in data size recorded in the blockchain affect the chain size. As a result, compared with our previous approach, we succeeded in suppressing increase in chain size by using the proposal approach; it was reduced the amount of increase in chain size about 73.0% when each node repeatedly shared about 2.8KB image data by 100 times..
62. Yao Xu, Hiroshi Koide, Danilo Vasconcellos Vargas, Kouichi Sakurai, Tracing MIRAI malware in networked system, 6th International Symposium on Computing and Networking Workshops, CANDARW 2018 Proceedings - 2018 6th International Symposium on Computing and Networking Workshops, CANDARW 2018, 10.1109/CANDARW.2018.00104, 534-538, 2018.12, In 2021, it is anticipated that there will be approximately 30 billion Internet of Things (IoT) devices. The tremendous aggregate value of the IoT makes it a tempting and lucrative target for cyber criminals. The breakout of Mirai malware, which compromises poorly secured IoT devices with factory-default username and passphrase to launch Distributed Denial of Service (DDoS) attacks, has raised broad awareness towards the need for increased IoT security. To better defend against Mirai infection and spread, it is critical to know how the malware operates as the first step. In this paper, we give a combined static and dynamic analysis of Mirai, basing on the results of which, we introduce the application of Threat Tracer. Threat tracer is an information system simulator initially developed to help design a system robust against Advanced Persistent Attacks(APT). It offers an intuitive track on how a cyber threat behaves in a complicated networked system. The feedback simultaneously contributes to revealing vulnerabilities of a system. Our work focuses on the replication of Mirai Malware's operating processes in Threat Tracer simulation. By achieving doing so, we believe it could offer a comprehensible description of how Mirai acts. Also, considering the continuous emergence of Mirai variants, the simulation serves as a predictor on upcoming threats' behavior patterns..
63. Yaokai Feng, Hitoshi Akiyama, Liang Lu, Kouichi Sakurai, Feature selection for machine learning-based early detection of distributed cyber attacks, 16th IEEE International Conference on Dependable, Autonomic and Secure Computing, IEEE 16th International Conference on Pervasive Intelligence and Computing, IEEE 4th International Conference on Big Data Intelligence and Computing and IEEE 3rd Cyber Science and Technology Congress, DASC-PICom-DataCom-CyberSciTec 2018 Proceedings - IEEE 16th International Conference on Dependable, Autonomic and Secure Computing, IEEE 16th International Conference on Pervasive Intelligence and Computing, IEEE 4th International Conference on Big Data Intelligence and Computing and IEEE 3rd Cyber Science and Technology Congress, DASC-PICom-DataCom-CyberSciTec 2018, 10.1109/DASC/PiCom/DataCom/CyberSciTec.2018.00040, 181-186, 2018.10, It is well known that distributed cyber attacks simultaneously launched from many hosts have caused the most serious problems in recent years including problems of privacy leakage and denial of services. Thus, how to detect those attacks at early stage has become an important and urgent topic in the cyber security community. For this purpose, recognizing C&C (Command & Control) communication between compromised bots and the C&C server becomes a crucially important issue, because C&C communication is in the preparation phase of distributed attacks. Although attack detection based on signature has been practically applied since long ago, it is well-known that it cannot efficiently deal with new kinds of attacks. In recent years, ML(Machine learning)-based detection methods have been studied widely. In those methods, feature selection is obviously very important to the detection performance. We once utilized up to 55 features to pick out C&C traffic in order to accomplish early detection of DDoS attacks. In this work, we try to answer the question that 'Are all of those features really necessary?' We mainly investigate how the detection performance moves as the features are removed from those having lowest importance and we try to make it clear that what features should be payed attention for early detection of distributed attacks. We use honeypot data collected during the period from 2008 to 2013. SVM(Support Vector Machine) and PCA(Principal Component Analysis) are utilized for feature selection and SVM and RF(Random Forest) are for building the classifier. We find that the detection performance is generally getting better if more features are utilized. However, after the number of features has reached around 40, the detection performance will not change much even more features are used. It is also verified that, in some specific cases, more features do not always means a better detection performance. We also discuss 10 important features which have the biggest influence on classification..
64. Yuto Nakano, Seira Hidano, Shinsaku Kiyomoto, Kouichi Sakurai, Active attack against oblivious RAM, 32nd IEEE International Conference on Advanced Information Networking and Applications, AINA 2018 Proceedings - 32nd IEEE International Conference on Advanced Information Networking and Applications, AINA 2018, 10.1109/AINA.2018.00112, 744-751, 2018.08, When a user consumes an encrypted digital content (for example video and music files), the player application accesses the secret key to decrypt the content. If the user is malicious, he can analyse the access pattern of the player application to extract the secret key efficiently. Oblivious RAMs (ORAMs) are effective solution for such threats. However, ORAMs are only effective for 'passive' attackers who can observe the RAM access done by the application, but cannot alter data stored on RAM. The attacker with ability to alter data on RAM can be called 'active' attackers. In this paper, we evaluate the security of ORAM schemes against active adversaries where they alter data on RAM and try to efficiently extract the secret information. We also propose countermeasures against active adversaries..
65. Jiawei Su, Danilo Vasconcellos Vargas, Sanjiva Prasad, Sgandurra Daniele, Yaokai Feng, Kouichi Sakurai, Lightweight Classification of IoT Malware Based on Image Recognition, 42nd IEEE Computer Software and Applications Conference, COMPSAC 2018 Proceedings - 2018 IEEE 42nd Annual Computer Software and Applications Conference, COMPSAC 2018, 10.1109/COMPSAC.2018.10315, 664-669, 2018.06, The Internet of Things (IoT) is an extension of the traditional Internet, which allows a very large number of smart devices, such as home appliances, network cameras, sensors and controllers to connect to one another to share information and improve user experiences. IoT devices are micro-computers for domain-specific computations rather than traditional functionspecific embedded devices. This opens the possibility of seeing many kinds of existing attacks, traditionally targeted at the Internet, also directed at IoT devices. As shown by recent events, such as the Mirai and Brickerbot botnets, DDoS attacks have become very common in IoT environments as these lack basic security monitoring and protection mechanisms. In this paper, we propose a novel light-weight approach for detecting DDos malware in IoT environments. We extract the malware images (i.e., a one-channel gray-scale image converted from a malware binary) and utilize a light-weight convolutional neural network for classifying their families. The experimental results show that the proposed system can achieve 94:0% accuracy for the classification of goodware and DDoS malware, and 81:8% accuracy for the classification of goodware and two main malware families..
66. Mosarrat Jahan, Mohsen Rezvani, Qianrui Zhao, Partha Sarathi Roy, Kouichi Sakurai, Aruna Seneviratne, Sanjay Jha, Light Weight Write Mechanism for Cloud Data, IEEE Transactions on Parallel and Distributed Systems, 10.1109/TPDS.2017.2782253, 29, 5, 1131-1146, 2018.05, Outsourcing data to the cloud for computation and storage has been on the rise in recent years. In this paper we investigate the problem of supporting write operation on the outsourced data for clients using mobile devices. We consider the Ciphertext-Policy Attribute-based Encryption (CP-ABE) scheme as it is well suited to support access control in outsourced cloud environments. One shortcoming of CP-ABE is that users can modify the access policy specified by the data owner if write operations are incorporated in the scheme. We propose a protocol for collaborative processing of outsourced data that enables the authorized users to perform write operation without being able to alter the access policy specified by the data owner. Our scheme is accompanied with a light weight signature scheme and simple, inexpensive user revocation mechanism to make it suitable for processing on resource-constrained mobile devices. The implementation and detailed performance analysis of the scheme indicate the suitability of the proposed scheme for real mobile applications. Moreover, the security analysis demonstrates that the security properties of the system are not compromised..
67. Shiqian Yu, Danilo Vasconcellos Vargas, Kouichi Sakurai, Effectively Protect Your Privacy
Enabling Flexible Privacy Control on Web Tracking, 5th International Symposium on Computing and Networking, CANDAR 2017 Proceedings - 2017 5th International Symposium on Computing and Networking, CANDAR 2017, 10.1109/CANDAR.2017.26, 533-536, 2018.04, Third-party tracking, which can collect the users' privacy when users are surfing the Internet, has garnered much attention. Nowadays tracker-blocking tools often use a ruleset based on the domains and elements that need to be blocked. This results in blocking all access tracking, even though the website shows no sign about tracking users' privacy. And what's more, although the tracker-blocking tools try their best to block all the third-party tracking, not all the users dislike the advertisement. Some of them think if their privacy is fine, it's all right to accept advertisements. In this paper, we present a novel framework by using Word2Vec to block third-party tracking. Our goal is to create more flexible and well-developed ruleset that can help users to protect their privacy according to their needs. Instead of blocking all access tracking, we decide to pay more attention to the websites that have a strong probability to collect the users' privacy. We use Word2Vec to classify the websites, and our results show that after using our framework, the error rate drops from 71% to 24%. We believe it brings the new blood into the field of web privacy by providing not only the new third-party tracking tool but also a novel way of thinking about how to block the third-party tracking..
68. Xiang You, Yaokai Feng, Kouichi Sakurai, Packet in Message Based DDoS Attack Detection in SDN Network Using OpenFlow, 5th International Symposium on Computing and Networking, CANDAR 2017 Proceedings - 2017 5th International Symposium on Computing and Networking, CANDAR 2017, 10.1109/CANDAR.2017.93, 2018-January, 522-528, 2018.04, Using the OpenFlow protocol, the virtual network technology SDN (Software Defined Network) is now widely used. In recent years, the number of DDoS attacks has been increasing year by year. To detect DDoS attacks in SDN, data recorded in the flow table in OpenFlow switch is analyzed and various detection methods are submitted. However, SDN centrally manages communication within the network, when detecting DDoS (Distributed Denial of Service) attacks. This creates a heavy processing load, and the processing load of the OpenFlow controller must be considered. In this paper, in order to reduce the processing load of the controller, we do not collect data of the flow table, extract three features from the Packet In message for communication between the controller and the switch, and perform real-time attack detection. Furthermore, to avoid stringent detection time intervals, triggers will be added before detection to realize light and dynamic DDoS attacks detection..
69. Somnath Panja, Sabyasachi Dutta, Kouichi Sakurai, Deniable Secret Handshake Protocol - Revisited, 33rd International Conference on Advanced Information Networking and Applications, AINA-2019 Advanced Information Networking and Applications - Proceedings of the 33rd International Conference on Advanced Information Networking and Applications AINA-2019, 10.1007/978-3-030-15032-7_106, 1266-1278, 2020.01, The notion of deniability ensures that the transcript generated in an interactive protocol does not yield any evidence of the interaction. In the context of key-exchange protocols for secure message transmission, the notion of deniability is well-explored. On the other hand, a secret handshake protocol enables a group of authorized users to establish a shared secret key and authenticate each other. Recently, a framework for deniable secret handshake is proposed by Tian et al. in ISPEC 2018. We analyze the protocol, show three flaws and give solutions to prevent them..
70. Yan Naung Soe, Yaokai Feng, Paulus Insap Santosa, Rudy Hartanto, Kouichi Sakurai, Implementing Lightweight IoT-IDS on Raspberry Pi Using Correlation-Based Feature Selection and Its Performance Evaluation, 33rd International Conference on Advanced Information Networking and Applications, AINA-2019 Advanced Information Networking and Applications - Proceedings of the 33rd International Conference on Advanced Information Networking and Applications AINA-2019, 10.1007/978-3-030-15032-7_39, 458-469, 2020.01, The application of many IoT devices is making our world more convenient and efficient. However, it also makes a large number of cyber-attacks possible because most IoT devices have very limited resources and cannot perform ordinary intrusion detection systems. How to implement efficient and lightweight IDS in IoT environments is a critically important and challenging task. Several detection systems have been implemented on Raspberry Pi, but most of them are signature-based and only allow limited rules. In this study, a lightweight IDS based on machine learning is implemented on a Raspberry Pi. To make the system lightweight, a correlation-based feature selection algorithm is applied to significantly reduce the number of features and a lightweight classifier is utilized. The performance of our system is examined in detail and the experimental result indicates that our system is lightweight and has a much higher detection speed with almost no sacrifice of detection accuracy..
71. Johjima Shota, Kosuke Kaneko, Subodh Sharma, Kouichi Sakurai, Simulation of Secure Volunteer Computing by Using Blockchain, 33rd International Conference on Advanced Information Networking and Applications, AINA-2019 Advanced Information Networking and Applications - Proceedings of the 33rd International Conference on Advanced Information Networking and Applications AINA-2019, 10.1007/978-3-030-15032-7_74, 883-894, 2020.01, Volunteer Computing (VC) is one of methods of distributed computing. In VC process, several volunteers provide their computing resources for some computational purposes. Because most VC is supposed to be executed based on a situation that each volunteer is an honest one, in a case that some malicious volunteers are inside the VC network, the VC contains potential risk of causing to output an unreliable computational result. To improve the reliability of the computational result, several existing VCs adopt a method of majority voting using reliability parameters. However, this method contains potential vulnerability against to “Sybil Attack”. Therefore, in this paper, we propose our VC system using blockchain technology named “Hierarchy-System” to solve these problems and also show the evaluation result executed on a VC system simulated our proposed method..
72. Hiroaki Anada, Takanori Yasuda, Junpei Kawamoto, Jian Weng, Kouichi Sakurai, RSA public keys with inside structure
Proofs of key generation and identities for web-of-trust, Journal of Information Security and Applications, 10.1016/j.jisa.2018.12.006, 45, 10-19, 2019.04, We propose a construction of the modulus of the RSA public keys for decentralized public-key trust generation like Web-of-Trust, where the modulus has inside structure. The first function of the structure is that it enables a peer to verify that the owner of the public key certainly generated the corresponding secret key. The second function is to tie up the public key with the owner's identity as well as her guarantors identities. Our construction is based on the modified version of the Lenstra's algorithm, by which a related second public key and the identity strings are embedded into the RSA modulus. The second public key is of the elliptic-curve cryptosystem (ECC) which has almost equivalent security level to the RSA cryptosystem. Our construction is applicable to a peer-to-peer network equipped with the blockchain of “consortium” and “trusted” type to yield a flat network that does not depends on PKI of the X.509 type..
73. Yasuyuki Sakai, Kouichi Sakurai, Efficient scalar multiplications on elliptic curves with direct computations of several doublings, IEICE Transactions on Fundamentals of Electronics, Communications and Computer Sciences, E84-A, 1, 120-129, 2001.01, We introduce efficient algorithms for scalar multiplication on elliptic curves defined over IFp. The algorithms compute 2kP directly from P, where P is a random point on an elliptic curve, without computing the intermediate points, which is faster than k repeated doublings. Moreover, we apply the algorithms to scalar multiplication on elliptic curves, and analyze their computational complexity. As a result of their implementation with respect to affine (resp. weighted projective) coordinates, we achieved an increased performance factor of 1.45 (45%) (resp. 1.15 (15%)) in the scalar multiplication of the elliptic curve of size 160-bit..
74. Shingo Miyazaki, Kouichi Sakurai, Moti Yung, On distributed cryptographic protocols for threshold RSA signing and decrypting with no dealer, IEICE Transactions on Fundamentals of Electronics, Communications and Computer Sciences, E84-A, 5, 1177-1184, 2001.01, We consider methods for threshold RSA decryption among distributed agencies without any dealer or trusted party. The first solution is a combination of two techniques by [9] and [7]. It demonstrates the feasibility of combining the distributed key generation and the RSA secure function application. The second solution is another approach making the distributed key distribution simpler and alleviating a burden of each shareholder in comparison with the first scheme. The latter scheme is newly developed technique based on [9] and further inspired by Simmons' protocol-failure of RSA (we believe that it is very interesting that a "protocol failure attack" be turned into a constructive method). Our comparison between these two schemes indicates a new measure of the performance of a distributed cryptographic protocol that consists of multiple stages..
75. Kouichi Sakurai, A Progress Report on Lattice Based Public-Key Cryptosystems -Theoretical Security versus Practical Cryptanalysis, IEICE Transactions on Information and Systems, E83-D, 3, 570-579, 2000.01, SUMMARY We review public-key cryptosystems from lattice problems which are inspired by Ajtai's remarkable result and consider their security from the point of view of both theory and practice. We also survey recent results on the power of the lattice reduction algorithm in cryptanalysis..
76. Shingo Miyazaki, Kouichi Sakurai, A practical off-line digital money system with partially blind signatures based on the discrete logarithm problem, IEICE Transactions on Fundamentals of Electronics, Communications and Computer Sciences, E83-A, 1, 106-108, 2000.01, We propose an untraceable electronic money system. Our system uses the partially blind signature based on the discrete logarithm problem, and applies secret key certificates to the payment protocol..
77. Yasuyuki Sakai, Kouichi Sakurai, On the practical performance of hyperelliptic curve cryptosystems in software implementation, IEICE Transactions on Fundamentals of Electronics, Communications and Computer Sciences, E83-A, 4, 692-701, 2000, We consider the performance of hyperelliptic curve cryptosystems over the fields Fp vs. F2n. We analyze the complexity of the group law of the jacobians JC (Fp) and JC (F2n) and compare their performance taking into consideration the effectiveness of the word size (32-bit or 64-bit) of the applied CPU (Alpha and Pentium) on the arithmetic of the definition field. Our experimental results show that JC(F2n) is faster than JC (Fp) on an Alpha, whereas JC (Fp) is faster than JC(F2n) on a Pentium. Moreover, we investigate the algorithm of the jacobian and the definition-field arithmetic to clarify our results from a practical point of view, with theoretical analysis..
78. Eisuke Dannoura, Kouichi Sakurai, An improvement on El-Yaniv-Fiat-Karp-Turpin's money-making bi-directional trading strategy, Information Processing Letters, 66, 1, 27-33, 1998.04.
79. Kouichi Sakurai, Practical proofs of knowledge without relying on theoretical proofs of membership on languages, Theoretical Computer Science, 10.1016/S0304-3975(96)00277-0, 181, 2, 317-335, 1997.07, Formulations and properties of proving possession of knowledge in interactive protocols are investigated. A four-move protocol for quadratic residuosity is proposed and a new notion of practical soundness is introduced based on its application to a cryptographic identification scheme. The role of cryptographic assumptions in arguments (i.e., computationally convincing proofs) of knowledge is also explored..
80. Kouichi Sakurai, Yuliang Zheng, On non-pseudorandomness from block ciphers with provable immunity against linear cryptanalysis, IEICE Transactions on Fundamentals of Electronics, Communications and Computer Sciences, E80-A, 1, 19-24, 1997.01, Weakness of a block cipher, which has provable immunity against linear cryptanalysis, is investigated. To this end, the round transformation used in MISTY, which is a data encryption algorithm recently proposed by M. Matsui from Mitsubishi Electric Corporation, is compared to the round transformation of DES from the point of view of pseudorandom generation. An important property of the MISTY cipher is that, in terms of theoretically provable resistance against linear and differential cryptanalysis, which are the most powerful cryptanalytic attacks known to date, it is more robust than the Data Encryption Standard or DES. This property can be attributed to the application of a new round transform in the MISTY cipher, which is obtained by changing the location of the basic round-function in a transform used in DES. Cryptographic roles of the transform used in the MISTY cipher are the main focus of this paper. Our research reveals that when used for constructing pseudorandom permutations, the transform employed by the MISTY cipher is inferior to the transform in DES, though the former is superior to the latter in terms of strength against linear and differential attacks. More specifically, we show that a 3-round (4-round, respectively) concatenation of transforms used in the MISTY cipher is not a pseudorandom (super pseudorandom, respectively) permutation. For comparison, we note that with three (four, respectively) rounds, transforms used in DES yield a pseudorandom (super pseudorandom, respectively) permutation. Another contribution of this paper is to show that a 3-round concatenation of transforms used in (the preliminary version of) the MISTY cipher has an algebraic property, which may open a door for various cryptanalytic attacks. These results clearly indicate that provable immunity against linear and differential cryptanalysis is not sufficient for designing a secure block cipher, and the security of the MISTY cipher will remain open until a close examination of its resistance is conducted against other cryptanalytic attacks than the linear or differential attack..
81. Akio Yanbe, Kouichi Sakurai, A short certificate of the number of universal optimal strategies for stopping simple stochastic games, Information Processing Letters, 10.1016/0020-0190(95)00181-6, 57, 1, 17-24, 1996.01.
82. Tatsuaki Okamoto, Kouichi Sakurai, Hiroki Shizuya, On the complexity of the discrete logarithm for a general finite group, IEICE Transactions on Fundamentals of Electronics, Communications and Computer Sciences, E79-A, 1, 61-65, 1996, GDL is the language whose membership problem is polynomial-time Turing equivalent to the discrete logarithm problem for a general finite group G. This paper gives a characterization of GDL from the viewpoint of computational complexity theory. It is shown that GDL ε NP ∩ co-AM, assuming that G is in NP ∩ co-NP, and that the group law operation of G can be executed in polynomial time of the element size. Furthermore, as a natural probabilistic extension, the complexity of GDL is investigated under the assumption that the group law operation is executed in an expected polynomial time of the element size. In this case, it is shown that GDL ε MA ∩ co-AM if G ε MA ∩ co-MA. As a consequence, we show that GDL is not NP-complete unless the polynomial time hierarchy collapses to the second level..
83. Kouichi Sakurai, Toshiya Itoh, Subliminal channels for transferring signatures
Yet another cryptographic primitive, IEICE Transactions on Fundamentals of Electronics, Communications and Computer Sciences, E77-A, 1, 31-38, 1994.01, This paper considers the subliminal channel, hidden in an identification scheme, for transferring signatures. We observe the direct parallelization of the Fiat-Shamir identification scheme has a subliminal channel for the transmission of the digital signature. A positive aspect of this hidden channel supplies us how to transfer signatures without secure channels. As a formulation of such application, we introduce a new notion called privately recordable signature. The privately recordable signature is generated in an interactive protocol between a signer and a verifier, and only the verifier can keep the signatures although no third adversary can record the signatures. In this scheme, then the disclosure of the verifier's private coin turns the signer's signature into the ordinary digital signature which is verified by anybody with the singer's public key. The basic idea of our construction suggests the novel primitive that a transferring securely signatures without secret channels could be constructed using only one-way function (without trapdoor)..
84. Toshiya Itoh, Kouichi Sakurai, Constant round perfect ZKIP of computational ability, IEICE Transactions on Fundamentals of Electronics, Communications and Computer Sciences, E76-A, 7, 1225-1233, 1993.07, In this paper, we show that without any unproven assumption, there exists a 'four' move blackbox simulation perfect zero-knowledge interactive proof system of computational ability for any random self-reducible relation R whose domain is in B P P, and that without any unproven assumption, there exists a 'four' move blackbox simulation perfect zero-knowledge interactive proof system of knowledge on the prime factorization. These results are optimal in the light of the round complexity, because it is shown that if a relation R has a three move blackbox simulation (perfect) zero-knowledge interactive proof system of computational ability (or of knowledge), then there exists a probabilistic polynomial time algorithm that on input x ε {0, 1}, outputs y such that (x,y) ε R with overwhelming probability if x ε dom R, and outputs '⊥' with probability 1 if x ε dom R..
85. Kouichi Sakurai, Characterization of languages in constant round perfect zero-knowledge interactive proofs, IEICE Transactions on Fundamentals of Electronics, Communications and Computer Sciences, E76-A, 4, 546-554, 1993.04, In this paper, we consider a class of the languages that have (constant round) perfect zero-knowledge interactive proofs without assuming any complexity assumptions. Especially, we investigate the interactive protocol with the restricted prover who runs in probabilistic polynomial time and knows the complete factorization as a trapdoor information of the integer associated with the input. We give a condition of the existence of constant round perfect zero-knowledge interactive proofs without assuming any complexity assumptions. The bit commitment based on the quadratic residuosity has an important role in our protocol and the simulation is based on the technique developed by Bellare, Micali, and Ostrovsky in Ref. (9), so call double running process. However, the proof of perfect zero-knowledgeness needs a more powerful simulation technique. Our simulation extracts more knowledge, the complete factorization of the integer associated with the input, from a (cheating) verifier than Bellare-Micali-Ostrovsky's simulation does. Furthermore, our main result implies that Blum integer has a five move perfect zero-knowledge interactive proof without assuming any complexity assumptions. (All previous known zero-knowledge protocols for Blum integer required either unproven cryptographic assumptions or unbounded number of rounds of message exchange.).
86. Tosyiya Itoh, Kouichi Sakurai, On the complexity of constant round ZKIP of possession of knowledge, IEICE Transactions on Fundamentals of Electronics, Communications and Computer Sciences, E76-A, 1, 31-39, 1993.01, In this paper, we investigate the round complexity of zero-knowledge interactive proof systems of possession of knowledge, and mainly show that if a relation R has a three move blackbox simulation zero-knowledge interactive proof system of possession of knowledge, then there exists a probabilistic polynomial time algorithm that can be satisfied under certain conditions. The result can be generalized to zero-knowledge interactive proof systems of possession of knowledge with more than four moves, because it s known that there exist a 'four' move blackbox simulation perfect zero-knowledge interactive proof system of possession of knowledge for a nontrivial relation R..
87. Kouichi Sakurai, Toshiya Itoh, Practical consequences of the discrepancy between zero-knowledge protocols and their parallel execution, IEICE Transactions on Fundamentals of Electronics, Communications and Computer Sciences, E76-A, 1, 14-22, 1993.01, In this paper, we investigate the discrepancy between a serial version and parallel version of zero-knowledge protocols, and clarify the information 'leaked' in the parallel version, which is not zero-knowledge unlike the case of the serial version. We consider two sides: one negative and the other positive in the parallel version of zero-knowledge protocols, especially of the Fiat-Shamir scheme..
88. Hiroaki Anada, Takanori Yasuda, Junpei Kawamoto, Jian Weng, Kouichi Sakurai, RSA public keys with inside structure
Proofs of key generation and identities for web-of-trust, Journal of Information Security and Applications, 10.1016/j.jisa.2018.12.006, 45, 10-19, 2019.04, We propose a construction of the modulus of the RSA public keys for decentralized public-key trust generation like Web-of-Trust, where the modulus has inside structure. The first function of the structure is that it enables a peer to verify that the owner of the public key certainly generated the corresponding secret key. The second function is to tie up the public key with the owner's identity as well as her guarantors identities. Our construction is based on the modified version of the Lenstra's algorithm, by which a related second public key and the identity strings are embedded into the RSA modulus. The second public key is of the elliptic-curve cryptosystem (ECC) which has almost equivalent security level to the RSA cryptosystem. Our construction is applicable to a peer-to-peer network equipped with the blockchain of “consortium” and “trusted” type to yield a flat network that does not depends on PKI of the X.509 type..
89. Satya Lokam, Sushmita Ruj, Kouichi Sakurai, BCC'18 chairs' welcome, 2nd ACM Workshop on Blockchains, Cryptocurrencies, and Contracts, BCC 2018 BCC 2018 - Proceedings of the 2nd ACM Workshop on Blockchains, Cryptocurrencies, and Contracts, Co-located with ASIA CCS 2018, iii, 2018.05.
90. Mosarrat Jahan, Suranga Seneviratne, Partha Sarathi Roy, Kouichi Sakurai, Aruna Seneviratne, Sanjay Jha, Light weight and fine-grained access mechanism for secure access to outsourced data*, Concurrency Computation, 10.1002/cpe.4736, 2018.01, In this paper, we explore the problem of providing selective read/write access to the outsourced data for clients using mobile devices in an environment that supports users from multiple domains and where attributes are generated by multiple authorities. We consider Ciphertext-Policy Attribute-based Encryption (CP-ABE) scheme as it can provide access control on encrypted outsourced data. One limitation of CP-ABE is that the users can modify the access policy specified by the data owner if write operations are introduced in the scheme. We propose a protocol for providing different levels of access to outsourced data that permits the authorized users to perform write operation without altering the access policy specified by the data owner. Our scheme provides fine-grained read/write access to the users, accompanied with a light weight signature scheme and computationally inexpensive user revocation mechanism suitable for resource-constrained mobile devices. We provide a theoretical analysis of the security of the proposed protocol and the experimental results measured from a real-world testbed..
91. Danilo Vasconcellos Vargas, Kouichi Sakurai, A Brief Review on Anomaly Detection and its Applications to Cybersecurity (情報通信システムセキュリティ), IEICE technical report, 116, 522, 37-42, 2017.03.
92. Kazuhide Fukushima, Shinsaku Kiyomoto, Toshiaki Tanaka, Kouichi Sakurai, Optimization of group key management structure with a client join-leave mechanism, Journal of Information Processing, 10.2197/ipsjjip.16.130, 16, 130-141, 2008.01, Many group key management schemes that reduce the total communication cost and/or the computational cost imposed on client devices have been proposed. However, optimizations of the key-management structure have not been studied. This paper proposes ways to optimize the key-management structure in a hybrid group key management scheme. The proposed method is able to minimize both the total communication cost and the computational cost imposed on client devices. First, we propose a probabilistic client join/leave model in order to evaluate the communication and computational costs of group key management schemes. This model idealizes client actions generally and considers the existence of the peaks of the joining/leaving frequency. Thus, we can analyze not only the average case scenario but also the worst case scenario using this model. Then, we formalize the total computation cost and the computational cost imposed on client devices in group key management schemes under the model. We present both an average case analysis and a worst case analysis. Finally, we show the parameters that minimize the total communication cost and the computational cost imposed on clients under the model. Our results should be useful in designing a secure group communication system for large and dynamic groups..
93. Kazuhide Fukushima, Shinsaku Kiyomoto, Toshiaki Tanaka, Kouichi Sakurai, Analysis of program obfuscation schemes with variable encoding technique, IEICE Transactions on Fundamentals of Electronics, Communications and Computer Sciences, 10.1093/ietfec/e91-a.1.316, E91-A, 1, 316-329, 2008, Program analysis techniques have improved steadily over the past several decades, and software obfuscation schemes have come to be used in many commercial programs. A software obfuscation scheme transforms an original program or a binary file into an obfuscated program that is more complicated and difficult to analyze, while preserving its functionality. However, the security of obfuscation schemes has not been properly evaluated. In this paper, we analyze obfuscation schemes in order to clarify the advantages of our scheme, the XOR-encoding scheme. First, we more clearly define five types of attack models that we defined previously, and define quantitative resistance to these attacks. Then, we compare the security, functionality and efficiency of three obfuscation schemes with encoding variables: (1) Sato et al.'s scheme with linear transformation, (2) our previous scheme with affine transformation, and (3) the XOR-encoding scheme. We show that the XOR-encoding scheme is superior with regard to the following two points: (1) the XOR-encoding scheme is more secure against a data-dependency attack and a brute force attack than our previous scheme, and is as secure against an information-collecting attack and an inverse transformation attack as our previous scheme, (2) the XOR-encoding scheme does not restrict the calculable ranges of programs and the loss of efficiency is less than in our previous scheme..
94. Tai Hoon Kim, Kouichi Sakurai, Definition of security practices in security management part of security level management model, International Journal of Security and its Applications, 2, 1, 63-71, 2008, To manage security level of IS, the first, organizations must be able to decide security level, the second, organizations must have procedures for building security countermeasures according to security level. For next step, organizations must be able to select areas where security countermeasures should be applied, and the last, organizations must be able to evaluate and improve the effect of security countermeasures. In this paper, we propose some essential elements for security level management of IS. These essential elements are expressed like as security practices, and in this paper, we propose some security practices related to security management area..
95. Kenichi Takahashi, Zhaoyu Liu, Kouichi Sakurai, Makoto Amamiya, A framework for user privacy protection using trusted programs, International Journal of Security and its Applications, 1, 2, 59-70, 2007.12, The evolution of mobile technologies enables us to realize ubiquitous computing environments. In such environments, a user's mobile terminal manages the sensitive information and assists in various activities based on the user's information. At the same time, information leakage will become a serious social problem. In this paper, we propose a framework to protect the sensitive information of users in a manner they consider safe. In the framework, the user provides a trusted program that implements the manner he/she considers safe. The information recipient accesses user's sensitive information through this trusted program. In this manner, the user can protect his/her sensitive information. However, there exist several challenges in the realization of this framework. In this paper, we propose a method for generating a trusted program and discuss the solutions to other challenges..
96. Jeong Ok Kwon, Ik Rae Jeong, Kouichi Sakurai, Dong Hoon Lee, Efficient verifier-based password-authenticated key exchange in the three-party setting, Computer Standards and Interfaces, 10.1016/j.csi.2006.12.002, 29, 5, 513-520, 2007.07, In the last few years, researchers have extensively studied the password-authenticated key exchange (PAKE) in the three-party setting. The fundamental security goal of PAKE is security against dictionary attacks. The protocols for verifier-based PAKE are additionally required to be secure against server compromise. Some verifier-based PAKE schemes in the three-party setting have been suggested to solve the server compromise problem. Unfortunately, the protocols are vulnerable to an off-line dictionary attack. In this paper, we present an efficient verifier-based PAKE protocol for three-parties that is secure against known-key attacks and provides forward secrecy. To the best of our knowledge, the proposed protocol is the first secure three-party verifier-based PAKE protocol in the literature..
97. Akitoshi Izumi, Yoshifumi Ueshige, Kouichi Sakurai, A proposal of key management scheme and its operation using
Anonymous biometrics on ID-based infrastructure, International Journal of Security and its Applications, 1, 1, 83-94, 2007.01, In the information exchange through network, the security risks always exist, that is eavesdropping, defacing, and spoofing by the attacker. PKI (Public Key Infrastructure) will prevent such attacks. But key management is very serious problem in PKI. The public key certificate is issued and distributed by certificate authority, but we think that the updating of expired certificate etc. are very costly for users. And secret key management is more serious problem. In order to solve above problems, we propose the scheme that stores protected secret key which is made by combination of biometrics and secret key in the smartcard in IDbased cryptography system. The user can restore the secret key from protected secret key by presenting his fingerprint to smartcard that has protected secret key and helper data. In our scheme, the template is not need for authentication. So, the problem of the template leakage won't arise. Lastly, we proposed the concrete operation scheme in which our scheme is used and how to make signature or authentication by applying our scheme. We show that the cost of the public key and secret key management will be reduced by using this operation scheme..
98. Shinsaku Kiyomoto, Kazuhide Fukushima, Toshiaki Tanaka, Kouichi Sakurai, On effectiveness of clock control in stream ciphers, IEICE Transactions on Fundamentals of Electronics, Communications and Computer Sciences, 10.1093/ietfec/e90-a.9.1780, E90-A, 9, 1780-1787, 2007.01, In this paper, we examine the effectiveness of clock control in protecting stream ciphers from a distinguishing attack, and show that this form of control is effective against such attacks. We model two typical clock-controlled stream ciphers and analyze the increase in computational complexity for these attacks due to clock control. We then analyze parameters for the design of clock-controlled stream ciphers, such as the length of the LFSR used for clock control. By adopting the design criteria described in this paper, a designer can find the optimal length of the clock-control sequence LFSR..
99. Chunhua Su, Jianying Zhou, Feng Bao, Guilin Wang, Kouichi Sakurai, Privacy-preservation techniques in data mining, Digital Privacy Theory, Technologies, and Practices, 187-226, 2007.01, In today’s information age, data collection is ubiquitous, and every transaction is recorded somewhere. The resulting data sets can consist of terabytes or even petabytes of data, so efficiency and scalability is the primary consideration of most data-mining algorithms. Data mining is becoming increasingly common in both the private and public sectors. Industries, such as banking, insurance, medicine, and retailing, commonly use data mining to reduce costs, enhance research, and increase sales. In the public sector, data-mining applications initially were used as a means to detect fraud and waste, but have grown to also be used for purposes, such as measuring and improving program performance..
100. Masakatu Morii, Shiho Moriai, Goichiro Hanaoka, Toru Akishita, Tetsuya Izu, Tetsu Iwata, Koji Okada, Toshinobu Kaneko, Hiroaki Kikuchi, Kwangjo Kim, Shinsaku Kiyomoto, Noboru Kunthiro, Hiroki Koga, Kazukuni Kobara, Ryuichi Sakai, Kouichi Sakurai, Kazue Sako, Takashi Satoh, Akira Shiozaki, Hiroki Shizuya, Tsuyoshi Takagi, Mitsuru Tada, Keisuke Tanaka, Hiroshi Doi, Toru Nakanishi, Shoichi Hirose, Eiichiro Fujisaki, Soichi Furuya, Mitsuru Matsui, Natsume Matsuzaki, Tsutomu Matsumoto, Atsuko Miyaji, Maid Yoshida, Special section on cryptography and information security, IEICE Transactions on Fundamentals of Electronics, Communications and Computer Sciences, 10.1093/ietfec/e90-a.1.1, E90-A, 1, 2007.01.
101. Masayuki Abe, Kazumaro Aoki, Giuseppe Ateniese, Roberto Avanzi, Zuzana Beerliová, Olivier Billet, Alex Biryukov, Ian Blake, Colin Boyd, Eric Brier, Aniello Castiglione, Juyoung Cha, Aldar Chan, Liqun Chen, Kookrae Cho, Scott Contini, Paolo D'Arco, Jintai Ding, Christophe Doche, Orr Dunkelman, Matthias Fitzi, Pierre Alain Fouque, Jacques J.A. Fournier, Kouichi Fujisaki, Eiichiro Fujisaki, Jun Furukawa, David Galindo, Shai Halevi, Helena Handschuh, Chris Heneghan, Thomas Holenstein, Fumitaka Hoshino, Yong Ho Hwang, Toshiyuki Isshiki, Ellen Jochemsz, Antoine Joux, Ari Juels, Charanjit Jutla, Aggelos Kiayias, Hiroaki Kikuchi, Tetsutarou Kobayashi, Tadayoshi Kohno, Hugo Krawczyk, Sandeep Kumar, Tanja Lange, Jung Wook Lee, Barbara Masucci, Alexander May, Miodrag Mihaljevic, Kazuhiko Minematsu, Fabian Monrose, Paul Montague, Steve Myers, David Naccache, Antonio Nicolosi, Satoshi Obana, Satomi Okazaki, Katsuyuki Okeya, Francis Olivier, Roger Oyono, Dan Page, Jung Hyung Park, Kun Peng, Krzysztof Pietrzak, Dominik Raub, Yasuyuki Sakai, Kouichi Sakurai, Werner Schindler, Jae Woo Seo, Jong Hoon Shin, Igor Shparlinski, Ron Steinfeld, Mike Szydlo, Yael Tauman Kalai, Isamu Teranishi, Toshio Tokita, Michael Tunstall, Frederik Vercauteren, Karine Villegas, Shabsi Walfish, Huaxiong Wang, Xiaofeng Wang, Bogdan Warinschi, Benne De Weger, Christopher Wolf, Alex Yampolskiy, Yeon Hyeong Yang, Yiqun Lisa Yin, Jeong Yoon, David Pointcheval, Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics)
Preface, Topics in Cryptology - CT-RSA 2006: The Cryptographers' Track at the RSA Conference 2006, Proceedings Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics), 3960 LNCS, 2006.07.
102. Laurence T. Yang, Hai Jin, Jianhua Ma, Theo Ungerer, David Ogle, Manish Parashar, Kouichi Sakurai, Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics)
Preface, Thrid International Conference on Autonomic and Trusted Computing, ATC 2006 Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics), 4158 LNCS, 2006.01.
103. Yasuyuki Sakai, Kouichi Sakurai, Simple power analysis on fast modular reduction with generalized Mersenne prime for elliptic curve cryptosystems, IEICE Transactions on Fundamentals of Electronics, Communications and Computer Sciences, 10.1093/ietfec/e89-a.1.231, E89-A, 1, 231-237, 2006.01, We discuss side channel leakage from modular reduction for NIST recommended domain parameters. FIPS 186-2 has 5 recommended prime fields. These primes have a special form which is referred to as generalized Mersenne prime. These special form primes facilitate especially efficient implementation. A typical implementation of efficient modular reduction with such primes includes conditional reduction. A conditional reduction in modular reduction can constitute an information channel on the secret exponent. Several researchers have produced unified code for elliptic point addition and doubling in order to avoid a simple power analysis (SPA). However, Walter showed that SPA still be possible if Montgomery multiplication with conditional reduction is implemented within the unified code. In this paper we show SPA on the modular reduction with NIST recommended primes, combining with the unified code for elliptic point operations. As Walter stated, our results also indicate that even if the unified codes are implemented for elliptic point operations, underlying field operations should be implemented in constant time. The unified approach in itself can not be a countermeasure for side channel attacks..
104. Yuko Murayama, Shinichi Kawamura, Hiroshi Yoshiura, Kouichi Sakurai, Kai Rannenberg, Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics)
Preface, Lecture Notes in Computer Science, 4266 LNCS, 2006.
105. Tai Hoon Kim, Kouichi Sakurai, Security countermeasure design for information systems by using block model, International Journal of Multimedia and Ubiquitous Engineering, 1, 2, 30-33, 2006, Because the networks and systems become more complex, the implementation of the security countermeasures becomes more critical consideration. The designers and developers of the security policy should recognize the importance of building security countermeasures by using both technical and non-technical methods, such as personnel and operational facts. Security countermeasures may be made for formulating an effective overall security solution to address threats at all layers of the information infrastructure. This paper uses the security engineering principles for determining appropriate security countermeasures. This paper proposes a method for building security countermeasures by modeling and dividing IT systems and security components into some blocks..
106. Sang Soo Yeo, Deok Gyu Lee, Kouichi Sakurai, Security protocol for IMT-2000-based contents service, International Journal of Multimedia and Ubiquitous Engineering, 1, 4, 11-20, 2006, IMT-2000 appeared in order to satisfy the desires of the uses who wish to supply through wireless most of the services being provided through wire, such as Internet services and multimedia high-speed data information.[1] However, during global roaming, the signal data and the user data get transmitted through the networks of other users. Also, it is judged that with the provision of high speed data communication the amount of data communication necessary for confidentiality protection will increase. It is planned that the recent IMT-2000 project will begin its commercial service in 2002. From this viewpoint, wireless contents, due to their special characteristics, are greatly exposed to illegal actions by third persons. As a result, it can be said that security and authentication issues in the mobile telecommunication environment are indispensable matters. For this purpose, it is intended that in this thesis through an analysis of the existent IMT-2000 authentication method, a more safe and efficient authentication method is presented and, at the same time, a security protocol necessary in the provision of wireless contents is designed..
107. Shinsaku Kiyomoto, Toshiaki Tanaka, Kouichi Sakurai, Experimental analysis of guess-and-determine attacks on clock-controlled stream ciphers, IEICE Transactions on Fundamentals of Electronics, Communications and Computer Sciences, 10.1093/ietfec/e88-a.10.2778, E88-A, 10, 2778-2791, 2005.10, Guess-and-Determine (GD) attacks have recently been proposed for the effective analysis of word-oriented stream ciphers. This paper discusses GD attacks on clock-controlled stream ciphers, which use irregular clocking for a non-linear function. The main focus is the analysis of irregular clocking for GD attacks. We propose GD attacks on a typical clock-controlled stream cipher AA5, and calculate the process complexity of our proposed GD attacks. In the attacks, we assume that the clocking of linear feedback shift registers (LFSRs) is truly random. An important consideration affecting the practicality of these attacks is the question of whether these assumptions are realistic. Because in practice, the clocking is determined by the internal states. We implement miniature ciphers to evaluate the proposed attacks, and show that they are applicable. We also apply the GD attacks to other clock controlled stream ciphers and compare them. Finally, we discuss some properties of GD attacks on clock-controlled stream ciphers and the effectiveness of the clock controllers. Our research results contain information that are useful in the design of clock-controlled stream ciphers..
108. Yong Sork Her, Kenji Imamoto, Kouichi Sakurai, Analysis and comparison of cryptographic techniques in e-voting and e-auction, Research Reports on Information Science and Electrical Engineering of Kyushu University, 10, 2, 91-96, 2005.09, Recently, many cryptographic techniques have been used for secure e-voting systems and e-auction systems. In this paper, we compare the used cryptographic techniques of e-voting systems with those of e-auction systems. We analyze advantages and disadvantages of various cryptographic techniques through e-voting systems and e-auction systems. Also, we discuss receipt-freeness which is one of the important requirements in e-voting systems and e-auction systems. Several receipt-free schemes have been proposed to prevent a vote-coercion (e-voting) or a bid-rigging (e-auction). In this paper, we analyze the existing receipt-free schemes and point out that the existing receipt-free schemes for the e-auction system do not prevent the bid-rigging. Moreover, we show the simulation results of computational costs in e-voting systems and e-auction systems which used the similar cryptographic techniques..
109. Hyung Chan Kim, R. S. Ramakrishna, Kouichi Sakurai, A collaborative role-based access control for trusted operating systems in distributed environment, IEICE Transactions on Fundamentals of Electronics, Communications and Computer Sciences, 10.1093/ietfec/E88-A.1.270, E88-A, 1, 270-279, 2005.01, The research communitiy has shown considerable interest in studying access control in single Trusted Operating Systems (TOS). However, interactions among multiple TOSs have attracted relatively little attention. In this paper, we propose a Collaborative Role-Based Access Control (C-RBAC) model for distributed systems in which accesses across system domain boundaries are allowed. Access entities in a TOS vary in time. The changes in the organizational structure of the access entities in one system may influence other cooperating systems. In addition, policy-freeness, domain and rule conflicts are possible. These problems restrict the flexibility and scalability of coordination. We propose drafting a meta-component to play the role of a coordinator in multi-domain role-based access control. It is then possible to impart flexibility and scalability in a secure fashion. Experimental studies of the proposed model with the Network File System and SELinux system support our conclusion..
110. Yasuyuki Sakai, Kouichi Sakurai, On the vulnerability of exponent recodings for the exponentiation against side channel attacks, IEICE Transactions on Fundamentals of Electronics, Communications and Computer Sciences, 10.1093/ietfec/E88-A.1.154, E88-A, 1, 154-160, 2005.01, In this paper we propose a new side channel attack, where exponent recodings for public key cryptosystems such as RSA and ECDSA are considered. The known side channel attacks and countermeasures for public key cryptosystems were against the main stage (square and multiply stage) of the modular exponentiation (or the point multiplication on an elliptic curve). We have many algorithms which achieve fast computation of exponentiations. When we compute an exponentiation, the exponent receding has to be carried out before the main stage. There are some exponent receding algorithms including conditional branches, in which instructions depend on the given exponent value. Consequently exponent receding can constitute an information channel, providing the attacker with valuable information on the secret exponent. In this paper we show new algorithms of attack on exponent receding. The proposed algorithms can recover the secret exponent, when the width-w NAF [9] and the unsigned/signed fractional window representation [5] are used. copyright.
111. Wook Shin, Jeong Gun Lee, Hong Kook Klm, Kouichi Sakurai, Procedural constraints in the extended RBAC and the coloured Petri net modeling, IEICE Transactions on Fundamentals of Electronics, Communications and Computer Sciences, 10.1093/ietfec/E88-A.1.327, E88-A, 1, 327-330, 2005.01, This paper presents the Coloured Petri Net modeling for security analysis of the Extended Role Based Access Control systems..
112. Satoshi Koga, Kouichi Sakurai, Proposal and analysis of a distributed online certificate status protocol with low communication cost, IEICE Transactions on Fundamentals of Electronics, Communications and Computer Sciences, 10.1093/ietfec/E88-A.1.247, E88-A, 1, 247-254, 2005.01, The Public Key Infrastructure (PKI) technology is very important to support the electronic commerce and digital communications on existing networks. The Online Certificate Status Protocol (OCSP) is the standard protocol for retrieving certificate revocation information in the PKI. To minimize the damages caused by OCSP responder's private key exposure, a distributed OCSP composed of multiple responders is needed. This paper presents a new distributed OCSP with a single public key by using key-insulated signature scheme. [6], In proposed distributed OCSP, each responder has the different private key, but corresponding public key remains fixed. Therefore the user simply obtains and stores one certificate, and can verify any responses by using a single public key..
113. Tetsuya Izu, Tetsu Iwata, Shiho Moriai, Tomoyuki Asano, Toshinobu Kaneko, Kwangjo Kim, Noboru Kunihiro, Hidenori Kuwakado, Hiroki Koga, Kazukuni Kobara, Ryuichi Sakai, Kouichi Sakurai, Takashi Satoh, Akira Shiozaki, Hideo Shimizu, Mitsuru Tada, Tsuyoshi Takagi, Keisuke Tanaka, Toshiaki Tanaka, Yukiyasu Tsunoo, Hiroshi Doi, Eiichiro Fujisaki, Soichi Furuya, Mitsuru Matsui, Tsutomu Matsumoto, Natsume Matsuzaki, Masahiro Mambo, Atsuko Miyaji, Yuko Murayama, Maki Yoshida, Hajime Watanabe, Akira Hayashi, Special section on cryptography and information security, IEICE Transactions on Fundamentals of Electronics, Communications and Computer Sciences, 10.1093/ietfec/E88-A.1.1, E88-A, 1, 2005.01.
114. Wonil Lee, Kouichi Sakurai, Seokhie Hong, Sangjin Lee, On the pseudorandomness of a modification of KASUMI type permutations, Lecture Notes in Computer Science, 3506, 313-329, 2005, We present a modification of KASUMI type permutations and analyze the security of it using the notion of pseudorandomness. Our modified KASUMI type permutation can be computed more efficiently than the original KASUMI type permutation. Furthermore, our results have a slightly better (same) upper bound of success probability against arbitrary attackers in the sense of (super) pseudorandomness..
115. Wonil Lee, Mridul Nandi, Palash Sarkar, Donghoon Chang, Sangjin Lee, Kouichi Sakurai, PGV-style block-cipher-based hash families and black-box analysis, IEICE Transactions on Fundamentals of Electronics, Communications and Computer Sciences, 10.1093/ietfec/E88-A.1.39, E88-A, 1, 39-48, 2005, In [1] it was proved that 20 of 64 PGV hash functions [2] based on block cipher are collision-resistant and one-way in the black-box model of the underlying block cipher. Here, we generalize the definition of PGV-hash function into a hash family and we will prove that, aside from the previously reported 20 hash functions, we have 22 more collision-resistant and one-way hash families. As all these 42 families are keyed hash family, these are also target-collision-resistant. All these 42 hash families have tight upper and lower bounds on (target) collision-resistant and one-way-ness..
116. Dong Guk Han, Tetsuya Izu, Jongin Lim, Kouichi Sakurai, Side channel cryptanalysis on XTR public key cryptosystem, IEICE Transactions on Fundamentals of Electronics, Communications and Computer Sciences, 10.1093/ietfec/e88-a.5.1214, E88-A, 5, 1214-1223, 2005, The XTR public key cryptosystem was introduced in 2000. XTR is suitable for a variety of environments including low-end smart cards, and is regarded as an excellent alternative to RSA and ECC. Moreover, it is remarked that XTR single exponentiation (XTR-SE) is less susceptible than usual exponentiation routines to environmental attacks such as the timing attack and the differential power analysis (DPA). This paper investigates the security of side channel attack (SCA) on XTR. In this paper, we show the immunity of XTR-SE against the simple power analysis if the order of the computation of XTR-SE is carefully considered. In addition, we show that XTR-SE is vulnerable to the data-bit DPA, the address-bit DPA, the doubling attack, the modified refined power analysis, and the modified zero-value attack. Moreover, we propose some countermeasures against these attacks. We also show experimental results of the efficiency of the countermeasures. From our implementation results, if we compare XTR with ECC with countermeasures against "SCAs." we think XTR is as suitable to smart cards as ECC..
117. SangCheol Hwang, NamHoon Lee, Kouichi Sakurai, GungGil Park, JaeCheol Ryou, The improved risk analysis mechanism in the practical risk analysis system, Unknown Journal, 3391, 835-842, 2005, The risk analysis system has a mechanism to evaluate and analysis the potential risk level in an organization IT system. To evaluate the Risk Level, it must be calculated the essential vulnerability that appear in various assets of organization, threats for these assets. These elements, vulnerabilities, threats and assets are the important factor to evaluate the risk level in an organization In this paper, we describe about design and implementation of a system using the practical risk analysis process that we propose. Furthermore we suggest the security countermeasure choice algorithm against the risk we found in an organization. Especially, The Security Countermeasure choice algorithm is implemented by using the Genetic-Algorithm restricted by some important factor. In this paper, we describe the design and implementation idea of the suggested genetic-algorithm module. Finally, We propose the main idea of the practical risk analysis process and the system using the risk analysis process that we propose in this paper..
118. Kwon Il Lee, Kouichi Sakurai, Jun Seok Lee, Jae Cheol Ryou, A DRM framework for secure distribution of mobile contents, Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics), 3090, 905-914, 2004.12, DRM technology allows content to be distributed in a controlled manner. Therefore, appropriate security mechanism is required. The Mobile DRM System is same as the general DRM system. Encryption technology is in use digital contents packaging. In case of Mobile DRM system, secure distribution and store of packaging encryption key is important. In this paper, we propose a DRM framework, SDRM (Secure mobile Digital Rights Management)*, to ensure secure distribution of mobile contents and rights. We considered being a secure DRM system to contain appropriate security solution..
119. Satoshi Koga, Kouichi Sakurai, A distributed online certificate status protocol with a single public key, Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics), 2947, 389-401, 2004.12, The Public Key Infrastructure (PKI) technology is very important to support secure global electronic commerce and digital communications on networks. The Online Certificate Status Protocol (OCSP) is the standard protocol for retrieving certificate revocation information in PKI. To minimize the damages caused by OCSP responder's private key exposure, a distributed OCSP composed of multiple responders is needed. This paper presents a new distributed OCSP with a single public key by using key-insulated signature scheme [6]. In proposed distributed OCSP, each responder has the different private key, but corresponding public key remains fixed, so the client simply obtains and stores one certificate and can verify any responses by using a single public key..
120. Wonil Lee, Mridul Nandi, Palash Sarkar, Donghoon Chang, Sangjin Lee, Kouichi Sakurai, A generalization of PGV-hash functions and security analysis in black-box model, Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics), 3108, 212-223, 2004.12, In [1] it was proved that 20 out of 64 PGV-hash functions [2] based on block cipher are collision resistant and one-way-secure in black-box model of the underlying block cipher. Here, we generalize the definition of PGV-hash function into a hash family and prove that besides the previous 20 hash functions we have 22 more collision resistant and one-way secure hash families. As all these 42 families are keyed hash families, these become target collision resistant also. All these 42 hash families have tight upper and lower bounds on (target) collision resistant and one-way-ness..
121. Kazuhide Fukushima, Kouichi Sakurai, A software fingerprinting scheme for java using classfiles obfuscation, Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics), 2908, 303-316, 2004.12, Embedding a personal identifier as a watermark to Java classfile is effective in order to protect copyrights of them. Monden et al.[1] proposed watermarking scheme that embeds arbitrary character sequence to the target method in a Java classfiles. But the scheme can be only used to embed the same watermark to each user's classfiles. Therefore, if we apply this scheme for embedding each user's personal identifier, the watermarks can be specified by comparing two or more users' Java classfiles. In this paper solve the problem by using "Classfiles Obfuscation" which is our obfuscation scheme for Java sourcecodes. By the scheme, we distribute all the methods among the all the Java classfiles at random. Evrey user's Java classfiles will have different structures respectively by appling "Clasfiles Obfuscation". As the result, to specify watermark by compareing classfiles will be difficult..
122. Dong Guk Han, Tetsuya Izu, Jongin Lim, Kouichi Sakurai, Modified power-analysis attacks on XTR and an efficient countermeasure, Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics), 3269, 305-317, 2004.12, In [HLS04a], Han et al. presented a nice overview of some side channel attacks (SCA), and some classical countermeasures. However, their proposed countermeasures against SCA are so inefficient that the efficiency of XTR with SCA countermeasures is at least 129 times slower than that of XTR without them. Thus they remained the construction of the efficient countermeasures against SCA as an open question. In this paper, we show that XTR can be also attacked by the modified refined power analysis (MRPA) and the modified zero-value attack (MZVA). To show validity of MRPA and MZVA on XTR, we give some numerical data of them. We propose a novel efficient countermeasure (XTR-RSE) against "SCAs": SPA, Data-bit DPA, Address-bit DPA, Doubling attack, MRPA, and MZVA. We show that XTR-RSE itself without other countermeasures is secure against all "SCAs". From our implementation results, if we compare XTR with ECC with countermeasures against "SCAs", we think XTR is as suitable to smart-cards as ECC due to the efficiency of the proposed XTR-RSE..
123. Satoshi Koga, Jae Cheol Ryou, Kouichi Sakurai, Pre-production methods of a response to certificates with the common status - Design and theoretical evaluation, Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics), 3093, 85-97, 2004.12, The Online Certificate Status Protocol provides the up-to-date response to certificate status queries. To reduce the risk of denial of service attacks, the responder can pre-produce responses. However this approach has the disadvantage that computational costs of the responder are inefficient since the responder should pre-produce one response message for each certificate. This paper proposes efficient pre-producing methods, which the responder can pre-produce a response message for each group consisting of certificates with the common status. In our methods, computational costs of the responder are efficient, compared with the previous pre-producing method..
124. Kouichi Sakurai, Special section on Discrete Mathematics and its applications, IEICE Transactions on Fundamentals of Electronics, Communications and Computer Sciences, E87-A, 5, 977, 2004.05.
125. Kenji Imamotoh, Kouichi Sakurai, Analysis and Design for Private Message Board Systems, IEICE Transactions on Fundamentals of Electronics, Communications and Computer Sciences, E87-A, 1, 204-211, 2004.01, When two parties connect via a possibly unreliable net-work, ensuring fairness becomes a serious problem. To solve this problem, a lot of Certified E-mail systems are proposed. However, user's privacy including confidentiality and anonymity is not considered in almost all of these systems. In this paper, we propose two private message board systems using an electronic notice board to solve Certified mail problem..
126. Yasuyuki Sakai, Kouichi Sakurai, A new attack with side channel leakage during exponent recoding computations, Lecture Notes in Computer Science, 3156, 298-311, 2004, In this paper we propose a new side channel attack, where exponent recodings for public key cryptosystems such as RSA and ECDSA are considered. The known side channel attacks and countermeasures for public key cryptosystems were against the main stage (square and multiply stage) of the modular exponentiation (or the point multiplication on an elliptic curve). We have many algorithms which achieve fast computation of exponentiations. When we compute an exponentiation, the exponent recoding has to be carried out before the main stage. There are some exponent recoding algorithms including conditional branches, in which instructions depend on the given exponent value. Consequently exponent recoding can constitute an information channel, providing the attacker with valuable information on the secret exponent. In this paper we show new algorithms of attack on exponent recoding. The proposed algorithms can recover the secret exponent, when the width-ω NAF [9] and the unsigned/signed fractional window representation [5] are used. Keywords: Side channel attack, exponent recoding, RSA cryptosystems, elliptic curve cryptosystems..
127. Junichiro Saito, Jae Cheol Ryou, Kouichi Sakurai, Enhancing privacy of universal re-encryption scheme for RFID tags, Lecture Notes in Computer Science, 3207, 879-890, 2004, A Radio-Frequency-Identification (RFID) tag is a small and cheap device which is combined in IC chip and an antenna for radio communications. It emits an ID in response to a query from a radio communication device called as a reader. For this reason, the RFID tag is used for management of goods and it is used as a substitute for a bar code. However, RFID system may infringe on a consumer's privacy because it has a strong tracing ability. Although ID of a RFID tag can be encrypted, it is possible to pursue an object by tracing specific information. Therefore, we discuss the privacy protection using universal re-encryption proposed by Golle, Jakobsson, Juels and Syverson. Since the system does not protect a modification of the information on RFID tags, it can be exploited by an attacker. Therefore we point out two attacks using modification of the information on RFID tags. Moreover, we offer two proposed schemes for addressing the problem..
128. Dong Guk Han, Jongin Lim, Kouichi Sakurai, On security of XTR public key cryptosystems against side channel attacks, Lecture Notes in Computer Science, 3108, 454-465, 2004, The XTR public key system was introduced at Crypto 2000. It is regarded that XTR is suitable for a variety of environments, including low-end smart cards, and XTR is the excellent alternative to either RSA or ECC. In [LV00a,SL01], authors remarked that XTR single exponentiation (XTR-SE) is less susceptible than usual exponentiation routines to environmental attacks such as timing attacks and Differential Power Analysis (DPA). In this paper, however, we investigate the security of side channel attack (SCA) on XTR. This paper shows that XTR-SE is immune against simple power analysis under assumption that the order of the computation of XTR-SE is carefully considered. However, we show that XTR-SE is vulnerable to Data-bit DPA, Address-bit DPA, and doubling attack. Moreover, we propose countermeasures that prevent the proposed attacks. As the proposed countermeasure against doubling attack is very inefficient, a good countermeasure against doubling attack is actually necessary to maintain the advantage of efficiency of XTR..
129. Kouichi Sakurai, Tsuyoshi Takagi, A reject timing attack on an IND-CCA2 public-key cryptosystem, Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics), 2587, 359-373, 2003.12, EPOC-2 is a public-key cryptosystem that can be proved IND-CCA2 under the factoring assumption in the random oracle model. It was written into a standard specification P1363 of IEEE, and it has been a candidate of the public-key cryptosystem in several international standards (or portfolio) on cryptography, e.g. NESSIE, CRYPTREC, ISO, etc. In this paper we propose a chosen ciphertext attack against EPOC-2 from NESSIE by observing the timing of the reject signs from the decryption oracle. We construct an algorithm, which can factor the public modulus using the difference of the reject symbols. For random 384-bit primes, the modulus can be factored with probability at least 1/2 by invoking about 385 times to the decryption oracle..
130. Jae Gwi Choi, Kouichi Sakurai, Ji Hwan Park, Does it need trusted third party? Design of buyer-seller watermarking protocol without trusted third party, Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics), 2846, 265-279, 2003.12, Buyer-seller watermarking protocol is a combination of traditional watermarking and fingerprinting techniques. For example, in applications where multimedia content is electronically distributed over a network, the content owner can embed a distinct watermark (a fingerprint), in each copy of the data that is distributed. If unauthorized copies of the data are found, then the origin of the copy can be determined by retrieving the unique watermark corresponding to each buyer. Recently, Ju and Kim proposed an anonymous buyer-seller watermarking protocol, where a buyer can purchase contents anonymously, but the anonymity can be controlled. They used two trusted parties: the watermark certification authority and the judge. The significance of this protocol is that it offered anonymity to watermarking protocol. But this protocol has the problem that honest buyers can be found as guilty, because sellers can recreate the same contents as the buyer's one if he/she colludes with the watermark certification authority and the judge. Thus this scheme must assume existence of the trusted third parties for its security. In this paper, we show shortcomings of this protocol and suggest a buyer-seller watermarking protocol that provides security of buyers and sellers without trusted third party..
131. Katsuyuki Okeya, Kouichi Sakurai, Fast multi-scalar multiplication methods on elliptic curves with precomputation strategy using montgomery trick, Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics), 2523, 564-578, 2003.12, Our development of efficient methods for the precomputation of multi-scalar multiplication for elliptic curve cryptosystems (ECCs) is presented. Multi-scalar multiplication is required in many forms of ECC, including schemes for the verification of ECDSA signatures. The simultaneous method is one known method for fast multi-scalar multiplication. The method has two stages: a precomputation stage and an evaluation stage. Points for use in the evaluation stage are computed in the precomputation stage. The actual multi-scalar multiplication is carried out on the basis of the precomputed points in the evaluation stage. In the evaluation stage of the simultaneous method, we are able to quickly compute the points of the multi-scalar multiple because few additions are required. On the other hand, if we use a large window width, we have to compute an enormous number of points in the precomputation stage. Hence, we have to compute an abundance of inversions, which carries a high computational cost. The result is that a large amount of time is required by the precomputation stage. This is the well-known draw-back of the simultaneous method. In our proposed method, we apply the Montgomery trick to reduce the number of inversions required with a width window w from O(22w) to O(w). In addition, our proposed method computes uP and vQ for any u,v, then compute uP + vQ, where P,Q are elliptic points. This procedure enables us to remove points that will not be used later from the process of precomputation. Without our proposed method, an algorithm to compute precomputation table would have to be changed dependently on unused points. Compared with the method without Montgomery trick, our proposed method is 3.6 times faster than the conventional simultaneous method, i.e., than in the absence of the Montgomery trick. Moreover, the optimal window width for our proposed method is 3, whereas the corresponding width for conventional simultaneous methods is 2..
132. Soichi Furuya, Kouichi Sakurai, Single-path authenticated-encryption scheme based on universal hashing, Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics), 2595, 94-109, 2003.12, An authenticated-encryption scheme is frequently used to provide a communication both with confidentiality and integrity. For stream ciphers, i.e., an encryption scheme using a cryptographic pseudorandom-number generator, this objective can be achieved by the simple combination of encryption and MAC generation. This naive approach, however, introduces the following drawbacks; the implementation is likely to require two scans of the data, and independent keys for the encryption and MAC generations must be exchanged. The single-path construction of an authenticated-encryption scheme for a stream cipher is advantageous in these two aspects but non-trivial design. In this paper we propose a single-path authenticated-encryption scheme with provable security. This scheme is based on one of the well-known ∈-almost-universal hash functions, the evaluation hash. The encryption and decryption of the scheme can be calculated by single-path operation on a plaintext and a ciphertext. We analyze the security of the proposed scheme and give a security proof, which claims that the security of the proposed scheme can be reduced to that of an underlying PRNG in the indistinguishability from random bits. The security model we use, real-or-random, is one of the strongest notions amongst the four well-known notions for confidentiality, and an encryption scheme with real-or-random sense security can be efficiently reduced to the other three security notions. We also note that the security of the proposed scheme is tight..
133. Keiichi Iwamura, Kouichi Sakurai, Hideki Imai, A secure digital watermark system for secondary distribution, Electronics and Communications in Japan, Part III: Fundamental Electronic Science (English translation of Denshi Tsushin Gakkai Ronbunshi), 10.1002/ecjc.1151, 86, 6, 76-85, 2003.06, Conventional digital watermark systems assume that the distributor (server) is a completely reliable organization. If the server is not a reliable organization, in a conventional system it is possible that suspicion may fall on a user who is not illegally distributing. Several methods have been proposed to handle this problem. In these methods, however, the system is essentially composed of two kinds of entities: the agent and the users. There is no discussion of a system composed of three entities - authors, agent, and users - where secondary distribution takes place from the author to an agent and then to the users. This paper proposes a digital watermark system that can prevent illegal conduct in a secondary distribution system composed of three types of entities - authors, agent, and users..
134. Yasuyuki Sakai, Kouichi Sakurai, An Efficient Representation of Scalars for Simultaneous Elliptic Scalar Multiplication, IEICE Transactions on Fundamentals of Electronics, Communications and Computer Sciences, E86-A, 5, 1135-1146, 2003.01, The computational performance of cryptographic protocols using an elliptic curve strongly depends on the efficiency of the scalar multiplication. Some elliptic curve based cryptographic protocols, such as signature verification, require computation of multi scalar multiplications of kP + lQ, where P and Q are points on an elliptic curve. An efficient way to compute kP + lQ is to compute two scalar multiplications simultaneously, rather than computing each scalar multiplication separately. We introduce new efficient algorithms for simultaneous scalar multiplication on an elliptic curve. We also give a detailed analysis of the computational efficiency of our proposed algorithms..
135. Katsuyuki Okeya, Kouichi Sakurai, Use of montgomery trick in precomputation of multi-scalar multiplication in elliptic curve cryptosystems, IEICE Transactions on Fundamentals of Electronics, Communications and Computer Sciences, E86-A, 1, 98-112, 2003.01, We develop efficient precomputation methods of multi-scalar multiplication on ECC. We should recall that multi-scalar multiplication is required in some elliptic curve cryptosystems including the signature verification of ECDSA signature scheme. One of the known fast computation methods of multi-scalar multiplication is a simultaneous method. A simultaneous method consists of two stages; precomputation stage and evaluation stage. Precomputation stage computes points of precomputation, which are used at evaluation stage. Evaluation stage computes multi-scalar multiplication using precomputed points. In the evaluation stage of simultaneous methods, we can compute the multi-scalar multiplied point quickly because the number of additions is small. However, if we take a large window width, we have to compute an enormous number of points in precomputation stage. Hence, we have to compute an abundance of inversions, which have large computational amount. As a result, precomputation stage requires much time, as well known. Our proposed method reduces from O(22w) inversions to O(w) inversions for a window width w, using Montgomery trick. In addition, our proposed method computes uP and vQ first, then compute uP + vQ, where P, Q are elliptic points. This procedure enables us to remove unused points of precomputation. Compared with the method without Montgomery trick, our proposed method is 3.6 times faster in the case of the precomputation stage for simultaneous sliding window NAF method with window width w = 3 and 160-bit scalars under the assumption that I/M = 30, S/M = 0.8, where I, M, S respectively denote computational amounts of inversion, multiplication and squaring on a finite field..
136. Keiichi Iwamura, Jun'ichi Hayashi, Kouichi Sakurai, Hideki Imai, “A Secure Fragile Watermarking”, Journal of the Institute of Image Electronics Engineers of Japan, 10.11371/iieej.32.22, 32, 1, 22-28, 2003.01, Previous fragile watermarking algorithms have been kept in secret, and not been discussed about the security except2).In 2), a secure fragile watermarking algorithm was proposed, even if it opens to the public. However, the algorithm needs to use different keys for different images. In this paper, we propose a fragile watermarking algorithm which can use the same key for different images. We show that this algorithm is secure, if it uses secure cryptographic function, pseudo-random number and self-synchronized pattern..
137. Katsuyuki Okeya, Kouichi Sakurai, A Simple Power Attack on a Randomized Addition-Subtraction Chains Method for Elliptic Curve Cryptosystems, IEICE Transactions on Fundamentals of Electronics, Communications and Computer Sciences, E86-A, 5, 1171-1180, 2003, We show that a randomized addition-subtraction chains countermeasure against side channel attacks is vulnerable to an SPA attack, which is a kind of side channel attack, under distinguishability between addition and doubling. The side channel attack takes advantage of information leaked during execution of a cryptographic procedure. The randomized addition-subtraction chains countermeasure was proposed by Oswald-Aigner, and is based on a random decision inserted into computations. However, the question of its immunity to side channel attacks is still controversial. The randomized addition-subtraction chains countermeasure has security flaw in timing attacks, another kind of side channel attack. We have implemented the proposed attack algorithm, whose input is a set of AD sequences, which consist of the characters "A" and "D" to indicate addition and doubling, respectively. Our program has clarified the effectiveness of the attack. The attack algorithm could actually detect secret scalars for given AD sequences. The average time to detect a 160-bit scalar was about 6 milliseconds, and only 30 AD sequences were enough to detect such a scalar. Compared with other countermeasures against side channel attacks, the randomized addition-subtraction chains countermeasure is much slower..
138. Yong Sork Her, Kouichi Sakurai, Analysis and design of SHA-V and RIPEMD-V with variable output-length, Research Reports on Information Science and Electrical Engineering of Kyushu University, 8, 1, 13-18, 2003, A hash function provides services of information security, authentication, integrity and non-reputation in a branch of information security. Cryptographic hash functions had been developed since MD4 was proposed by Rivest. U. S standard of a hash function is SHA-1 with 160 bits of output length. RIPEMD was designed in 1992 by den Boer and others under the RIPE project. When we consider the improvement of computation ability and speed, it can be difficult to guarantee the security of a hash function with 160 bits of output length. It is required a hash function with variable output length that can take a suitable output length by systems. HAVAL is the first hash function with variable output length, which was proposed by Zheng et al. HAS-V based on HAVAL-1 was proposed by N. K. Park et al. In this paper, we design two hash functions with variable output length, namely SHA-V and RIPEMD-V. based on SHA-1 and RIPEMD-1, and analyze the security on two designed hash functions..
139. Yong Sork Her, Kouichi Sakurai, On the security of yet another reduced version of 3-pass HAVAL, Unknown Journal, 137, 2003, We find collisions for the first and third passes of 3-pass HAVAL (following HAVAL[1,3]) which is not using the second pass and not successive two passes. To find a collision in HAVAL[1,3], we introduce the scheme of S.W.Park et al..
140. Yasuyuki Sakai, Kouichi Sakurai, Timing attack against implementation of a parallel algorithm for modular exponentiation, Lecture Notes in Computer Science, 2846, 319-330, 2003, We describe a parallel algorithm for modular exponentiation y ≡ xk mod n. Then we discuss timing attacks against an implementation of the proposed parallel algorithm for modular exponentiation. When we have two processors, which perform modular exponentiation, an exponent k is scattered into two partial exponents k(0) and k(1), where k(0) and k(1) are derived by bitwise AND operation from k such that k(0) = k ∧ (0101⋯01)2 and k(1) = k ∧(1010 ⋯10)2. Two partial modular exponentiations y0 ≡ xk(0) mod n and y1 ≡ xk(1) mod n are performed in parallel using two processors. Then we can obtain y by computing y ≡ y0y1 mod n. In general, the hamming weight of k(0) and k(1) are smaller than that of k. Thus fast computation of modular exponentiation y ≡ xk mod n can be achieved. Moreover we show a timing attack against an implementation of this algorithm. We perform a software simulation of the attack and analyze security of the parallel implementation..
141. Katsuyuki Okeya, Kouichi Sakurai, A scalar multiplication algorithm with recovery of the y-coordinate on the montgomery form and analysis of efficiency for elliptic curve cryptosystems, IEICE Transactions on Fundamentals of Electronics, Communications and Computer Sciences, E85-A, 1, 84-93, 2002, We present a scalar multiplication algorithm with recovery of the y-coordinate on a Montgomery-form elliptic curve over any non-binary field. The previous algorithms for scalar multiplication on a Montgomery form do not consider how to recover the y-coordinate. So although they can be applicable to certain restricted schemes (e.g. ECDH and ECDSA-S), some schemes (e.g. ECDSA-V and MQV) require scalar multiplication with recovery of the y-coordinate. We compare our proposed scalar multiplication algorithm with the traditional scalar multiplication algorithms (including Window-methods on the Weierstrass form), and discuss the Montgomery form versus the Weierstrass form in the performance of implementation with several techniques of elliptic curve cryptosystems (including ECES, ECDSA, and ECMQV). Our results clarify the advantage of the cryptographic usage of Montgomery-form elliptic curve in constrained environments such as mobile devices and smart cards..
142. Yasuyuki Sakai, Kouichi Sakurai, Speeding up elliptic scalar multiplication using multidoubling, IEICE Transactions on Fundamentals of Electronics, Communications and Computer Sciences, E85-A, 5, 1075-1083, 2002, We discuss multidoubling methods for efficient elliptic scalar multiplication. The methods allows computation of 2k P directly from P without computing the intermediate points, where P denotes a randomly selected point on an elliptic curve. We introduce algorithms for elliptic curves with Montgomery form and Weierstrass form defined over finite fields with characteristic greater than 3 in terms of affine coordinates. These algorithms are faster than k repeated doublings. Moreover, we apply the algorithms to scalar multiplication on elliptic curves and analyze computational complexity. As a result of our implementation with respect to the Montgomery and Weierstrass forms in terms of affine coordinates, we achieved running time reduced by 28% and 31%, respectively, in the scalar multiplication of an elliptic curve of size 160-bit over finite fields with characteristic greater than 3..
143. Kouichi Sakurai, A theory of demonstrating program result-correctness with cryptographic applications, IEICE Transactions on Information and Systems, E84-D, 1, 4-14, 2001.01, We formalize a model of "demonstration of program result-correctness," and investigate how to prove this fact against possible adversaries, which naturally extends Blum's theory of program checking by adding zero-knowledge requirements. The zero-knowledge requirements are universal for yes and no instances alike..
144. Fangming Zhao, Yoshiaki Hori, Kouichi Sakurai, Analysis of existing privacy-preserving protocols in domain name system, IEICE Transactions on Information and Systems, 10.1587/transinf.E93.D.1031, E93-D, 5, 1031-1043, 2010, In a society preoccupied with gradual erosion of electronic privacy, loss of privacy in the current Domain Name System is an important issue worth considering. In this paper, we first review the DNS and some security & privacy threats to make average users begin to concern about the significance of privacy preservation in DNS protocols. Then, by an careful survey of four noise query generation based existing privacy protection approaches, we analyze some benefits and limitations of these proposals in terms of both related performance evaluation results and theoretic proofs. Finally, we point out some problems that still exist for research community's continuing efforts in the future..
145. Akihiro Sakai, Yoshiaki Hori, Kouichi Sakurai, Behavior control based on dynamic code translation, 2010 10th Annual International Symposium on Applications and the Internet, SAINT 2010 Proceedings - 2010 10th Annual International Symposium on Applications and the Internet, SAINT 2010, 10.1109/SAINT.2010.103, 375-378, 2010, When analyzing the behaviors of an existing binary code, it is difficult because need to learn about special technologies. Moreover, static analysis is also difficult to detect the malicious behaviors if codes are encrypted by themselves. In this paper, we propose the method of dynamic change of program behavior, and avoid executing malicious codes intentionally. In order to make it possible, we plan to generalize it to separate dynamic analysis codes from dynamic analysis technologies as reusable programming approach..
146. Seiichiro Mizoguchi, Yoshiro Fukushima, Yoshiaki Kasahara, Yoshiaki Hori, Kouichi Sakurai, Darknet monitoring on real-operated networks, 5th International Conference on Broadband Wireless Computing, Communication and Applications, BWCCA 2010 Proceedings - 2010 International Conference on Broadband, Wireless Computing Communication and Applications, BWCCA 2010, 10.1109/BWCCA.2010.82, 278-285, 2010, Darknet monitoring is an effective method to analyze malicious activities on networks including the Internet. Since there is no legitimate host on darknets, traffic sent to such a space is considered to be malicious. There are two major issues for darknet monitoring: how to prepare unused address space and how to configure network sensors deployed on the network. Preparation of monitoring addresses is difficult, and it have not been obvious yet what an appropriate configuration is. To solve the first issue, we proposed a method for network monitoring by exploiting unused IP addresses on segments managed by DHCP server, where is a real-operated network. By assigning these addresses, we can easily obtain IP addresses for monitoring and enable network monitoring on production network. Furthermore, we conducted real darknet monitoring experiments and clarified what kind of information could be obtained. We deployed several types of sensors on real-operated network and captured darknet traffic. After analyzing the traffic, we compared the data between each sensor. We found that there were dramatic differences between the data collected by each sensor and our proposed method was useful for real network monitoring..
147. Ilsun You, Jong Hyouk Lee, Kouichi Sakurai, Yoshiaki Hori, ESS-FH
Enhanced security scheme for fast handover in hierarchical mobile IPv6, IEICE Transactions on Information and Systems, 10.1587/transinf.E93.D.1096, E93-D, 5, 1096-1105, 2010, Fast Handover for Hierarchical Mobile IPv6 (F-HMIPv6) that combines advantages of Fast Handover for Mobile IPv6 (FMIPv6) and Hierarchical Mobile IPv6 (HMIPv6) achieves the superior performance in terms of handover latency and signaling overhead compared with previously developed mobility protocols. However, without being secured, F-HMIPv6 is vulnerable to various security threats. In 2007, Kang and Park proposed a security scheme, which is seamlessly integrated into FHMIPv6. In this paper, we reveal that Kang-Park's scheme cannot defendagainst the Denial of Service (DoS) and redirect attacks while largely relying on the group key. Then, we propose an Enhanced Security Scheme for F-HMIPv6 (ESS-FH) that achieves the strong key exchange and the key independence as well as addresses the weaknesses of Kang-Park's scheme. More importantly, it enables fast handover between different MAP domains. The proposed scheme is formally verified based on BAN-logic, and its handover latency is analyzed and compared with that of Kang-Park's scheme..
148. Laiping Zhao, Yizhi Ren, Yang Xiang, Kouichi Sakurai, Fault-Tolerant Scheduling with Dynamic Number of Replicas in Heterogeneous Systems, 2010 12th IEEE International Conference on High Performance Computing and Communications, HPCC 2010 Proceedings - 2010 12th IEEE International Conference on High Performance Computing and Communications, HPCC 2010, 10.1109/HPCC.2010.72, 434-441, 2010, In the existing studies on fault-tolerant scheduling, the active replication schema makes use of ε + 1 replicas for each task to tolerate ε failures. However, in this paper, we show that it does not always lead to a higher reliability with more replicas. Besides, the more replicas implies more resource consumption and higher economic cost. To address this problem, with the target to satisfy the user's reliability requirement with minimum resources, this paper proposes a new fault tolerant scheduling algorithm: MaxRe. In the algorithm, we incorporate the reliability analysis into the active replication schema, and exploit a dynamic number of replicas for different tasks. Both the theoretical analysis and experiments prove that the MaxRe algorithm's schedule can certainly satisfy user's reliability requirements. And the MaxRe scheduling algorithm can achieve the corresponding reliability with at most 70% fewer resources than the FTSA algorithm..
149. Liang Zhao, Di Xiao, Kouichi Sakurai, Image encryption design based on multi-dimensional matrix map and partitioning substitution and diffusion-integration substitution network structure, 2010 International Conference in Information Science and Applications, ICISA 2010 2010 International Conference on Information Science and Applications, ICISA 2010, 10.1109/ICISA.2010.5480269, 2010, Multimedia security is already one of the most crucial problems in information science. Specially, as the character of digital image, the traditional cipher such as DES and RSA are not suitable for being applied to encrypt the digital image. Therefore, the study of image encryption scheme attracts the interest of large researchers. Nowadays, a variety of image encryption methods have been proposed with several kinds of structures. Many of them can finish the encryption process effectively. However, most of them are only based on encryption of two phases: substitution and diffusion, which is a traditional framework. In order to achieve an exceptional encryption effect, this paper presents a novel encryption structure named as PSDIS network(Partitioning Substitution and Diffusion-Integration Substitution network). Based on this structure, a corresponding encryption algorithm is designed utilizing the generalized multidimensional Arnold cat map and PSD-IS network structure. The experimental results and their analyses demonstrate that the proposed scheme is secure and meets the requirement of image encryption..
150. Seiichiro Mizoguchi, Yuji Kugisaki, Yoshiaki Kasahara, Yoshiaki Hori, Kouichi Sakurai, Implementation and evaluation of bot detection scheme based on data transmission intervals, 2010 6th IEEE Workshop on Secure Network Protocols, NPSec 2010 2010 6th IEEE Workshop on Secure Network Protocols, NPSec 2010, 10.1109/NPSEC.2010.5634446, 73-78, 2010, Botnet is one of the most considerable issues in the world. A host infected with a bot is used for collecting personal information, launching DoS attacks, sending spam e-mail and so on. If such a machine exists in an organizational network, that organization will lose its reputation. We have to detect these bots existing in organizational networks immediately. Several network-based bot detection methods have been proposed; however, some traditional methods using payload analysis or signature-based detection scheme are undesirable in large amount of traffic. Also there is a privacy issue with looking into payloads, so we have to develop another scheme that is independent of payload analysis. In this paper, we propose a bot detection method which focuses on data transmission intervals. We distinguish human-operated clients and bots by their network behaviors. We assumed that a bot communicates with C&C server periodically and each interval of data transmission will be the same. We found that we can detect such behaviors by using clustering analysis to these intervals. We implemented our proposed algorithm and evaluated by testing normal IRC traffic and bot traffic captured in our campus network. We found that our method could detect IRC-based bots with low false positives..
151. Laiping Zhao, Yizhi Ren, Mingchu Li, Kouichi Sakurai, SPSE
A flexible QoS-based service scheduling algorithm for service-oriented Grid, 2010 IEEE International Symposium on Parallel and Distributed Processing, Workshops and Phd Forum, IPDPSW 2010 Proceedings of the 2010 IEEE International Symposium on Parallel and Distributed Processing, Workshops and Phd Forum, IPDPSW 2010, 10.1109/IPDPSW.2010.5470920, 2010, With the development of the Grid computing, increased attention is paid to services and user personalization. How to search and schedule the most suitable service for an end user direct affects the popularization use of service oriented Grid. Inspired from the mode of web search engine, such as Yahoo, Google, this paper proposes an innovative service searching and scheduling algorithm (SPSE: Service Providers Search Engine) for the Grid. The SPSE sorts all services from Internet and returns the most appropriate ones to the end user. Compared with the existing scheduling algorithms, our method is much more flexible in meeting user's QoS requirements, especially supporting the multiobjective and user personalization. The related simulation experiments show that our method performs well in scalability, and can capture user's preferences value precisely and automatically..
152. Guojun Wang, Laurence T. Yang, Kouichi Sakurai, Special section on trust, security and privacy for pervasive applications, IEICE Transactions on Information and Systems, E93-D, 3, 409-410, 2010, The special section of The Institute of Electronics, Information and Communication Engineers Journal presents Trust, Security and Privacy for Pervasive Applications and aims at bringing together researchers and practitioners in the world working on related issues. In order to achieve these goals, an editorial committee for this special section was organized to publish new research results on this area. The editorial committee thanks all the authors who submitted their papers to this special section, which made this special section come true. They also thank all the reviewers who spent a lot of time on reviewing these papers with a lot of valuable comments and suggestions, which made it easy to select high-quality papers..
153. Fumiharu Etoh, Kenichi Takahashi, Yoshiaki Hori, Kouichi Sakurai, Study of log file dispersion management method, 2010 10th Annual International Symposium on Applications and the Internet, SAINT 2010 Proceedings - 2010 10th Annual International Symposium on Applications and the Internet, SAINT 2010, 10.1109/SAINT.2010.104, 371-374, 2010, In system equipment, a mechanism to prevent the manipulation or deletion of log information and log files by an attacker and to maintain the contents of log files are essential. Because log files include an active event and an operation event in the system equipment, these files are at risk of attacks such as file manipulation or deletion. In this paper, we propose a log file dispersion management method using hash values. It is possible to detect the manipulation or deletion of log information and log files and to reconstruct original log files. Further, this method has both redundancy and resistibility..
154. Huafei Zhu, Tadashi Araragi, Takashi Nishide, Kouichi Sakurai, Universally composable non-committing encryptions in the presence of adaptive adversaries, International Conference on Security and Cryptography, SECRYPT 2010 SECRYPT 2010 - Proceedings of the International Conference on Security and Cryptography, 389-398, 2010, Designing non-committing encryptions tolerating adaptive adversaries is a challenging task. In this paper, a simple implementation of non-committing encryptions is presented and analyzed in the strongest security model. We show that the proposed non-committing encryption scheme is provably secure against adaptive adversaries in the universally composable framework assuming that the decisional Diffie-Hellman problem is hard..
155. Jingyu Hua, Mingchu Li, Kouichi Sakurai, Yizhi Ren, Efficient intrusion detection based on static analysis and stack walks, 4th International Workshop on Security, IWSEC 2009 Advances in Information and Computer Security - 4th International Workshop on Security, IWSEC 2009, Proceedings, 10.1007/978-3-642-04846-3_11, 5824 LNCS, 158-173, 2009.12, Some intrusion detection models such as the VPStatic first construct a behavior model for a program via static analysis, and then perform intrusion detection by monitoring whether its execution is consistent with this behavior model. These models usually share the highly desirable feature that they do not produce false alarms but they face the conflict between precision and efficiency. The high precision of the VPStatic is at the cost of high space complexity. In this paper, we propose a new context-sensitive intrusion detection model based on static analysis and stack walks, which is similar to VPStatic but much more efficient, especially in memory use. We replace the automaton in the VPStatic with a state transition table (STT) and all redundant states and transitions in VPStatic are eliminated. We prove that our STT model is a deterministic pushdown automaton (DPDA) and the precision is the same as the VPStatic. Experiments also demonstrate that our STT model reduces both time and memory costs comparing with the VPStatic, in particular, memory overheads are less than half of the VPStatic's. Thereby, we alleviate the conflict between precision and efficiency..
156. Yizhi Ren, Mingchu Li, Yongrui Cui, Cheng Guo, Kouichi Sakurai, Enhancing cooperative behavior for online reputation systems by group selection, Symposia and Workshops on Ubiquitous, Autonomic and Trusted Computing in Conjunction with the UIC'09 and ATC'09 Conferences, UIC-ATC 2009 UIC-ATC 2009 - Symposia and Workshops on Ubiquitous, Autonomic and Trusted Computing in Conjunction with the UIC'09 and ATC'09 Conferences, 10.1109/UIC-ATC.2009.81, 568-573, 2009.12, Reputation systems are very useful in large online communities in which users may frequently have the opportunity to interact with users with whom they have no prior experience. Recently, how to enhance the cooperative behaviors in the reputation system that has became to one of the key open issues. Research in the evolutionary game theory shows that the group selection or multilevel selection can favor the cooperation in the finite populations. Furthermore, Nowak et al., in [1], [2] give a fundamental condition for the evolution of cooperation by group selection.Based on the above important result, we extend the group selection concept in evolutionary biology and propose a group-based mechanism to enhance cooperation for online reputation systems..
157. Akihiro Sakai, Yoshiaki Hori, Kouichi Sakurai, Formal verification for access control in web information sharing system, 3rd International Conference on Information Security and Assurance, ISA 2009 Advances in Information Security and Assurance - Third International Conference and Workshops, ISA 2009, Proceedings, 10.1007/978-3-642-02617-1_9, 5576 LNCS, 80-89, 2009.11, When we write access-control description of the Web Applications using the group and the role, there is a problem that it is difficult for a user to decide the joint ownership partner of data. Therefore, there are the trials for describing access-control using social networks. However, unexpected defects might sneak in this description if it is marked in a careless manner. In this paper, we propose the formal definition of the access-control description consist of the first-order predicate logic for the automatic checking..
158. Amril Syalim, Yoshiaki Hori, Kouichi Sakurai, Grouping provenance information to improve efficiency of access Control, 3rd International Conference on Information Security and Assurance, ISA 2009 Advances in Information Security and Assurance - Third International Conference and Workshops, ISA 2009, Proceedings, 10.1007/978-3-642-02617-1_6, 5576 LNCS, 51-59, 2009.11, Provenance is defined in some literature as a complete documentation of process that led to an object. Provenance has been utilized in some contexts, i.e. database systems, file systems and grid systems. Provenance can be represented by a directed acyclic graph (DAG). In this paper we show an access control method to the provenance information that is represented by a directed acyclic graph and a method to improve efficiency of access control by grouping the provenance information. The idea of our model is that by controlling access to nodes, edges and paths in the provenance graph we may build an expressive access control model to the provenance graph. We improve the efficiency of access control model by grouping some provenance information. In our model, the provenance information is stored in a relational database. Before explaining our idea, we describe provenance store, provenance representation, and how to store provenance graph in a relational database..
159. Kazuhide Fukushima, Shinsaku Kiyomoto, Toshiaki Tanaka, Kouichi Sakurai, Ternary subset difference method and its quantitative analysis, 9th International Workshop on Information Security Applications, WISA 2008 Information Security Applications - 9th International Workshop, WISA 2008, Revised Selected Papers, 10.1007/978-3-642-00306-6_17, 5379 LNCS, 225-239, 2009.11, This paper proposes a ternary subset difference method (SD method) that is resistant to coalition attacks. In order to realize a secure ternary SD method, we design a new cover-finding algorithm, label assignment algorithm, and encryption algorithm. These algorithms are required to revoke one or two subtrees simultaneously while maintaining resistance against coalition attacks. We realize this two-way revocation mechanism by creatively using labels and hashed labels. Then, we evaluate the efficiency and security of the ternary SD method. We show that the upper bound of the average message length in the ternary SD method is smaller by about 12.2 percent than that of the conventional SD method, and the number of labels on each client device can be reduced by about 20.4 percent. On the other hand, the computational cost imposed on a client device stays within O(logn). Finally, we prove that the ternary SD method is secure against coalition attacks..
160. Kouichi Sakurai, Ilsun You, Bonam Kim, Feilong Tang, The 3rd International workshop on intelligent, mobile and internet services in ubiquitous computing (IMIS 2009)
Welcome message from IMIS 2009 organizers, Proceedings of the International Conference on Complex, Intelligent and Software Intensive Systems, CISIS 2009, 10.1109/CISIS.2009.212, 2009.10.
161. Chunhua Su, Justin Zhan, Kouichi Sakurai, Importance of data standardization in privacy-preserving k-means clustering, International Workshops on Database Systems for Advanced Applications, DASFAA 2009: BenchmarX, MCIS, WDPP, PPDA, MBC, PhD Database Systems for Advanced Applications - DASFAA 2009 International Workshops BenchmarX, MCIS, WDPP, PPDA, MBC, PhD, 10.1007/978-3-642-04205-8_23, 5667 LNCS, 276-286, 2009.09, Privacy-preserving k-means clustering assumes that there are at least two parties in the secure interactive computation. However, the existing schemes do not consider the data standardization which is an important task before executing the clustering among the different database. In this paper, we point out without data standardization, some problems will arise from many applications of data mining. Also, we provide a solution for the secure data standardization in the privacy-preserving k-means clustering..
162. Kenichi Takahashi, Yoshiki Mitsuyuki, Tsunenori Mine, Kouichi Sakurai, Makoto Amamiya, Design and implementation of security mechanisms for a hierarchical community-based multi-agent system, 10th Pacific Rim International Conference on Multi-Agents, PRIMA 2007 Agent Computing and Multi-Agent Systems - 10th Pacific Rim International Conference on Multi-Agents, PRIMA 2007, Revised Papers, 10.1007/978-3-642-01639-4_12, 5044 LNAI, 134-145, 2009.07, Recently, several community-based systems have been developed; however, almost all such systems have been developed as Webserver- based systems. Thus, server administrator can easily eavesdrop on user communications, since they have to send/receive information through the server. Therefore, we propose multi-agent-based peer-topeer (P2P) system wherein each peer manages his/her information and exchanges it with other peers directly. This, thus, resolves the problems posed byWeb-server-based systems; however, we have to consider attacks from malicious third parties. This study designs and implements security protocols/mechanisms for a hierarchical community-based multi-agent system. Furthermore, if we consider a practical use case, we should be able to demonstrate that the proposed system can be implemented by combining it with existing security techniques for more reliable and rapid deployment. Finally, we evaluate the performance of the proposed security system and present an example application..
163. Yi Han, Akihiro Sakai, Yoshiaki Hori, Kouichi Sakurai, Improving the quality of protection of web application firewalls by a simplified taxonomy of web attacks, Advances in Information Security and Its Application Third International Conference, ISA 2009, Proceedings, 10.1007/978-3-642-02633-1_14, 36, 105-110, 2009.07, Nowadays, with over 70% of attacks carried out over the web application level, organizations need all the help they can get in making their system secure. Web Application Firewalls (WAFs) are among the tools that are commonly used for the prevention of Web attacks. However, the WAFs provide very little protection on their own. In order to become useful, they must be configured with rules. Unfortunately, the rule configuration process is not easy and error-prone, thus the quality of protection(QoP) of WAFs is still behind our expectations. In this paper, we investigate the current WAFs and point out some of their problems regarding about the poor QoP. We then analyze the origins of these problems and propose two decision modules, the attack-decision module and priority-decision module based on a proposed simplified taxonomy of web attacks which are helpful for improving the QoP of WAFs. Finally, we conclude our work and show future interests to extend our modules to IDS systems..
164. Bin Hui Chou, Kenichi Takahashi, Yoshiaki Hori, Kouichi Sakurai, Reconsidering data logging in light of digital forensics, Advances in Information Security and Its Application Third International Conference, ISA 2009, Proceedings, 10.1007/978-3-642-02633-1_15, 36, 111-118, 2009.07, Logs record the events that have happened within in a system so they are considered the history of system activities. They are one of the objects that digital forensic investigators would like to examine when a security incident happens. However, logs were initially created for trouble shooting, and are not purposefully designed for digital forensics. Thus, enormous and redundant log data make analysis tasks complicated and time-consuming to find valuable information, and make logging-related techniques difficult utilized in some systems such as embedded systems. In this paper, we reconsider a data logging mechanism in terms of forensics and consequently, we propose purpose-based forensic logging. In purpose-based forensic logging, we only collect the required logs according to a specific purpose, which could decrease the space that logs occupy and may mitigate the analysis tasks during forensic investigations..
165. Ilsun You, Kouichi Sakurai, Yoshiaki Hori, A security analysis on Kempf-Koodli's security scheme for Fast Mobile IPv6, IEICE Transactions on Communications, 10.1587/transcom.E92.B.2287, E92-B, 6, 2287-2290, 2009.06, Recently, the security scheme, proposed by Kempf and Koodli, has been adopted as a security standard for Fast handover for Mobile IPv6. But, it does not prevent denial of service attacks while resulting in high computation cost. More importantly, we find that it is still vulnerable to redirection attacks because it fails to secure the Unsolicited Neighbor Advertisement messages. In this paper, Kempf-Koodli's scheme is formally analyzed through BAN-logic and its weaknesses are demonstrated..
166. Cheng Guo, Mingchu Li, Kouichi Sakurai, A new secret sharing scheme based on the multi-dealer, IEICE Transactions on Fundamentals of Electronics, Communications and Computer Sciences, 10.1587/transfun.E92.A.1373, E92-A, 5, 1373-1378, 2009.01, Almost all the existing secret sharing schemes are based on a single dealer. Maybe in some situations, the secret needs to be maintained by multiple dealers. In this paper, we proposed a novel secret sharing scheme based on the multi-dealer by means of Shamir's threshold scheme and T. Okamoto and S. Uchiyama's public-key cryptosystem. Multiple dealers can commonly maintain the secret and the secret can be dynamically renewed by any dealer. Meanwhile, the reusable secret shadows just needs to be distributed only once. In the secret updated phase, the dealer just needs to publish a little public information instead of redistributing the new secret shadows. Its security is based on the security of Shamir's threshold scheme and the intractability of factoring problem and discrete logarithm problem..
167. Kohei Tatara, Kouichi Sakurai, A signature scheme associated with universal re-signcryption, International Conference on Availability, Reliability and Security, ARES 2009 Proceedings - International Conference on Availability, Reliability and Security, ARES 2009, 10.1109/ARES.2009.104, 780-785, 2009, Today, with increasing deversity of network technologies, people have been likely to be insterested in anonymity. The attacker might threaten anonymity of senders and receivers by confirming linkability between their sessions. Recently, Golle et al. proposed the re-encryption scheme applicable to Mix, called Universal Re-encryption. In this scheme, a ciphertext is supposed to be re-encrypted without public information corresponding to it. Moreover, only a subject that re-enctypts a ciphertext can know the correspondence of original ciphertext and it, and the computational complexity to break the unlinkability property is equal to the semantic secrecy. In this paper, we consider and improve the Universal Re-encryption scheme, and propose a scheme that can verify who transmit the message by adding the property of signature..
168. Yongrui Cui, Mingchu Li, Yizhi Ren, Kouichi Sakurai, An adaptive reputation-based algorithm for grid virtual organization formation, IEICE Transactions on Fundamentals of Electronics, Communications and Computer Sciences, 10.1587/transfun.E92.A.1339, E92-A, 5, 1339-1346, 2009, A novel adaptive reputation-based virtual organization formation is proposed. It restrains the bad performers effectively based on the consideration of the global experience of the evaluator and evaluates the direct trust relation between two grid nodes accurately by consulting the previous trust value rationally. It also consults and improves the reputation evaluation process in PathTrust model by taking account of the inter-organizational trust relationship and combines it with direct and recommended trust in a weighted way, which makes the algorithm more robust against collusion attacks. Additionally, the proposed algorithm considers the perspective of the VO creator and takes required VO services as one of the most important fine-grained evaluation criterion, which makes the algorithm more suitable for constructing VOs in grid environments that include autonomous organizations. Simulation results show that our algorithm restrains the bad performers and resists against fake transaction attacks and badmouth attacks effectively. It provides a clear advantage in the design of a VO infrastructure..
169. Ilsun You, Kouichi Sakurai, Yoshiaki Hori, An enhanced security protocol for fast mobile IPv6, IEICE Transactions on Information and Systems, 10.1587/transinf.E92.D.1979, E92-D, 10, 1979-1982, 2009, Recently, Kempf and Koodli have proposed a security protocol for Fast Mobile IPv6 (FMIPv6). Through the SEcure Neighbor Discovery (SEND) protocol, it achieves secure distribution of a handover key, and consequently becomes a security standard for FMIPv6. However, it is still vulnerable to redirection attacks. In addition, due to the SEND protocol, it suffers from denial of service attacks and expensive computational cost. In this paper, we present a security protocol, which enhances Kempf-Koodli's one with the help of the AAA infrastructure..
170. Ilsun You, Kouichi Sakurai, Yoshiaki Hori, Comments on Kang-Park's security scheme for fast handover in hierarchical mobile IPv6, 4th International Conference on Frontier of Computer Science and Technology, FCST 2009 4th International Conference on Frontier of Computer Science and Technology, FCST 2009, 10.1109/FCST.2009.75, 351-355, 2009, While gracefully combining FMIPv6 and HMIPv6 together, F-HMIPv6 enables the best performance in terms of handover latency and signaling overhead. Recently, to protect F-HMIPv6, Kang and Park proposed a security scheme. This scheme successfully achieves seamless integration with F-HMIPv6 while providing the session key exchange as well as the mobile node authentication. In this paper, Kang-Park's scheme is formally verified based on BAN-logic, and then its weaknesses and related attacks are discussed..
171. Amril Syalim, Yoshiaki Hori, Kouichi Sakurai, Comparison of risk analysis methods
Mehari, magerit, NIST800-30 and microsoft's security management guide, International Conference on Availability, Reliability and Security, ARES 2009 Proceedings - International Conference on Availability, Reliability and Security, ARES 2009, 10.1109/ARES.2009.75, 726-731, 2009, In this paper we compare four risk analysis methods: Mehari, Magerit, NIST800-30 and Microsoft's Security Management Guide. Mehari is a method for risk analysis and risk management developed by CLUSIF (Club de la Sécurité de l'Information Français). Magerit is a risk analysis and management methodology for information systems developed by CSAE (Consejo Superior de Administración Electrónica). NIST800-30 is a risk management guide for information technology systems recommended by the National Institute of Standard and Technology (NIST) in NIST Special Publication 800-30. Microsoft's Security Management Guide is a security risk management guide developed by Microsoft. In this paper, we compare those methods based on two main criteria: the first criterion is the steps that are used by the methods to conduct the risk assessment, the second one is the contents of the methods and supplementary documents provided with them. We found that all methods follow the first three general steps of risk analysis. However, the Mehari method, the Magerit method and the Microsoft Security Management Guide do not include control recommendations. Control recommendations in these methods are proposed as the next step to security management (i.e. after risk analysis). All methods provide a detailed guide for risk analysis. However, only three methods - Mehari, Magerit and the one proposed in the Microsoft Security Management Guide-provide supplementary documents for risk assessment..
172. Runhe Huang, Jianhua Ma, Kenichi Takahashi, Kouichi Sakurai, Design and object-oriented implementation of an intelligence entity sharing pool, 2009 WRI Global Congress on Intelligent Systems, GCIS 2009 Proceedings of the 2009 WRI Global Congress on Intelligent Systems, GCIS 2009, 10.1109/GCIS.2009.269, 2, 583-587, 2009, One of the challenges for ubiquitous intelligence computing is how to enable ubiquitous devices (u-devices) certain levels of intelligent/smart/ autonomic/ processing capabilities. Due to their limited capacity and processing power, it is difficult to embed such capabilities into u-devices. The idea is to design an intelligence entity sharing pool in which an intelligence entity can be dynamically composed from a number of atomic intelligence entities and/or complex intelligence entities. This research has two phases: (1) how to design the intelligence entity sharing pool; and (2) how to share an intelligence entity in the sharing pool. The second phase is completely upon the first phase as the premise. This paper is mainly focused on presenting our design ideas of the intelligence entity sharing pool in the following aspects: (1) defining atomic intelligence entity and complex intelligence entity; (2) designing an appropriate structure for storing atomic/complex intelligence entities; and (3) designing mechanisms for composition and decomposition of intelligence entity/entities..
173. Chunhua Su, Feng Bao, Jianying Zhou, Tsuyoshi Takagi, Kouichi Sakurai, Distributed noise generation for density estimation based clustering without trusted third party, IEICE Transactions on Fundamentals of Electronics, Communications and Computer Sciences, 10.1587/transfun.E92.A.1868, E92-A, 8, 1868-1871, 2009, The rapid growth of the Internet provides people with tremendous opportunities for data collection, knowledge discovery and cooperative computation. However, it also brings the problem of sensitive information leakage. Both individuals and enterprises may suff er from the massive data collection and the information retrieval by distrusted parties. In this paper, we propose a privacy-preserving protocol for the distributed kernel density estimation-based clustering. Our scheme applies random data perturbation (RDP) technique and the verifiable secret sharing to solve the security problem of distributed kernel density estimation in [4] which assumed a mediate party to help in the computation..
174. Masayoshi Kohara, Yoshiaki Hori, Kouichi Sakurai, Heejo Lee, Jae Cheol Ryou, Flow traffic classification with support vector machine by using payload length, 2009 2nd International Conference on Computer Science and Its Applications, CSA 2009 Proceedings of the 2009 2nd International Conference on Computer Science and Its Applications, CSA 2009, 10.1109/CSA.2009.5404180, 2009, Classifying traffic is an important task for effective network planning and design, and monitoring the trends of the applications in operational networks. In this paper, we propose flow traffic classification methods using support vector machine. Classifying traffic is an important task for effective network planning and design, and monitoring the trends of the applications in operational networks. The proposals satisfy the following three requirements. Using to only flow information, not using port numbers, automatic making of traffic models. In this paper, we provide an empirical evaluation of our proposals using datasets of MIT Lincoln Laboratory, which illustrates that our proposals can classify network traffic flow over 90 % precision..
175. Kouichi Sakurai, Foreword
Special section on information and communication system security, IEICE Transactions on Information and Systems, E92-D, 5, 765, 2009.
176. Guojun Wang, Peter Mueller, Kouichi Sakurai, Maria S. Perez-Hernandez, Message from the trustcom 2009 symposium chairs, Proceedings - 12th IEEE International Conference on Computational Science and Engineering, CSE 2009, 10.1109/CSE.2009.524, 2, 2009.
177. Yizhi Ren, Mingchu Li, Kouichi Sakurai, Modeling security bridge certificate authority architecture, IEICE Transactions on Fundamentals of Electronics, Communications and Computer Sciences, 10.1587/transfun.E92.A.1544, E92-A, 6, 1544-1547, 2009, Current Public Key Infrastructures suffer from a scaling problem, and some may have security problems, even given the topological simplification of bridge certification authorities. This paper analyzes the security problems in Bridge Certificate Authorities (BCA) model by using the concept of "impersonation risk," and proposes a new modified BCA model, which enhances its security, but is a bit more complex incertification path building and implementation than the existing one..
178. Kohei Tatara, Yoshiaki Hori, Kouichi Sakurai, Polymorphic worm detection by analyzing maximum length of instruction sequence in network packets, International Conference on Availability, Reliability and Security, ARES 2009 Proceedings - International Conference on Availability, Reliability and Security, ARES 2009, 10.1109/ARES.2009.103, 972-977, 2009, Intrusion detection system records worm's signature, and detects the attack that lurks in traffic based on it. However, to detect the worm that corrects, and changes some oneself, a highly accurate detection technique for distinguishing the code that seems to be the worm included in traffic is requested. In this paper, we pay attention to the Toth et al.'s method to extract the executable code included in the data flows on the network and detect the attack by measuring the length of them. Then, we describe the problem of their method and how to solve it..
179. Ryuzou Nishi, Yoshiaki Hori, Kouichi Sakurai, Secrecy capacity of wireless LAN, International Conference on Availability, Reliability and Security, ARES 2009 Proceedings - International Conference on Availability, Reliability and Security, ARES 2009, 10.1109/ARES.2009.91, 905-910, 2009, We address secure secret key distribution in wireless communication systems. There is the secrecy capacity concept that it can distribute information which the third parties can not eavesdrop because of the noise over the distribution channel. Then, we address secure secret key distribution in wireless communication systems using secrecy capacity concept. Wireless channel is noisier compared with wired channel. Specifically, we investigate about wiretap channel coding that it can implement in the existing wireless LAN systems. We have investigated the coding parameters and the conditions that it can implement..
180. Tatsuro Fujii, Yizhi Ren, Yoshiaki Hori, Kouichi Sakurai, Security analysis for P2P routing protocols, International Conference on Availability, Reliability and Security, ARES 2009 Proceedings - International Conference on Availability, Reliability and Security, ARES 2009, 10.1109/ARES.2009.82, 899-904, 2009, In P2P systems, nodes use a plenty of styles flooding the messages to the destination or discover the target node. Therefore, it is important to guarantee the efficiency and security of message routing between the source and the destination. Unfortunately, malicious attackers can easily insert a lot of nodes they controlled, and disturb the message routing between honest nodes. In order to counter such attacks, secure routing protocols which ensure successful message routing are needed. Furthermore, it is very important to analyze existing routing protocols for the inventions of secure routing protocols. In this paper, we propose a security model for evaluating security level of routing protocol. In this model, we define the concept of Regular Path, and use it as the indicator of security level. Then, we analyze three representative routing protocols based on proposed model to make comparisons from the aspects of security level and implement level. The simulation and the related theory have proven that Conditional Probability of Regular Path(CPRP) is mainly affected by the scale of network and malicious nodes rate in the network. The results can help to choose a reasonable routing protocol of the context-based application, or give some basic guideline for the invention of the new routing protocol..
181. Chunhua Su, Feng Bao, Jianying Zhou, Tsuyoshi Takagi, Kouichi Sakurai, Security and correctness analysis on privacy-preserving k-means clustering schemes, IEICE Transactions on Fundamentals of Electronics, Communications and Computer Sciences, 10.1587/transfun.E92.A.1246, E92-A, 4, 1246-1250, 2009, Due to the fast development of Internet and the related IT technologies, it becomes more and more easier to access a large amount of data. k-means clustering is a powerful and frequently used technique in data mining. Many research papers about privacy-preserving k-means clustering were published. In this paper, we analyze the existing privacy-preserving k-means clustering schemes based on the cryptographic techniques. We show those schemes will cause the privacy breach and cannot output the correct results due to the faults in the protocol construction. Furthermore, we analyze our proposal as an option to improve such problems but with intermediate information breach during the computation..
182. Laiping Zhao, Mingchu Li, Weifeng Sun, Kouichi Sakurai, Yizhi Ren, The optimal choice by resource consumers in Grid market, Symposia and Workshops on Ubiquitous, Autonomic and Trusted Computing in Conjunction with the UIC'09 and ATC'09 Conferences, UIC-ATC 2009 UIC-ATC 2009 - Symposia and Workshops on Ubiquitous, Autonomic and Trusted Computing in Conjunction with the UIC'09 and ATC'09 Conferences, 10.1109/UIC-ATC.2009.75, 580-585, 2009, Market mechanism is effective to encourage more people to participate in the Grid environment. Applying economic principles to Grid is deemed promising to improve the overall value provided by such participants. However, resource scheduling algorithms are different depending on different needs. In this paper, we mainly focus on the consumers' own interest. Assuming that the consumers are selfish and what they concern about is lower cost and higher success rate, we improve the HRED algorithm using hierarchical mechanism and resource selection mechanism, which cooperate with resource providers' trust degree, making it more suitable, practical and credible for Grid market. The experiments prove that the improved HRED algorithm works faster especially when there are large numbers of resource providers in Grid market, and it also gives much higher success rates in the non-credible Grid environment..
183. Yizhi Ren, Mingchu Li, Cheng Guo, Yongrui Cui, Kouichi Sakurai, Trust similarity measure in trust model for P2P networks, 5th International Conference on Embedded and Ubiquitous Computing, EUC 2008 Proceedings of The 5th International Conference on Embedded and Ubiquitous Computing, EUC 2008, 10.1109/EUC.2008.137, 2, 107-112, 2008.12, Trust and reputation have become important research topics in P2P networks. Traditional researches can hardly adaptable to each separate peer's needs and preferences which are common concern in trust and reputation system. This paper proposes two methods of similarity measure in trust model, which develop to reflect the difference of peers' preference and improve the sensitiveness of detecting peers' behaviors..
184. Bin Hui Chou, Kohei Tatara, Taketoshi Sakuraba, Yoshiaki Hori, Kouichi Sakurai, A secure virtualized logging scheme for digital forensics in comparison with kernel module approach, 2nd International Conference on Information Security and Assurance, ISA 2008 Proceedings of the 2nd International Conference on Information Security and Assurance, ISA 2008, 10.1109/ISA.2008.96, 421-426, 2008.09, Digital forensics encompasses the process of identifying the perpetrator and the criminal method by analyzing the logs generated in the computer. Log files record the activities of the computer and by reading them one can know what kind of event happened at a certain time. Therefore, secure logs with the integrity property are essential. In this paper, we discuss two approaches to achieve the integrity of logsthe kernel module and virtualization, and compare them. Although virtualization is more inefficient in performance than the kernel module, it provides more security properties for logs. Thus, we then focus on the virtualization approach with a detailed proposal, which describes ways to preserve logs without tampering and deletion..
185. Seong Moo Yoo, Bonam Kim, Hui Huang Hsu, Ilsun You, Jong Hyuk Park, Minyi Guo, Ching Hsien Hsu, David Simplot-Ryl, Edwin H.M. Sha, Hai Jin, Javier Lopez, Shu Ching Chen, Tatsuya Yamazaki, Junmo Yang, Wen Tzeng Huang, Akiyo Nadamoto, Chengcui Zhang, Ching Sheng Wang, Chunming Rong, Frode Eika Sandnes, Geyong Min, Howard Leung, Hyobeom Ahn, Hyunju Kim, Indrakshi Ray, Isabelle Simplot-Ryl, Ismail Khalil Ibrahim, Javier García-Villalba, Jemal H. Abawajy, Jinhua Guo, Jon Youn, Kouichi Sakurai, Kuei Ping Shih, Lawrence Y. Deng, Mei Ling Shyu, Mohammad Al-Shurman, Oh Heum Kwon, Pedro M. Ruiz, Pilar Herrero, Q. Shi, Qun Jin, Seungjin Park, Sang Hyuk Son, Whai En Chen, Witold Pedrycz, Xiaofeng Chen, Yin Fu Huang, IMIS 2008 message from the workshop organizers MUE 2008, 2008 International Conference on Multimedia and Ubiquitous Engineering, MUE 2008 Proceedings - 2008 International Conference on Multimedia and Ubiquitous Engineering, MUE 2008, 10.1109/MUE.2008.7, 2008.09.
186. Ryuzou Nishi, Yoshiaki Hori, Kouichi Sakurai, Key distribution scheme using matched filter resistant against DoS attack, 22nd International Conference on Advanced Information Networking and Applications Workshops/Symposia, AINA 2008 Proceedings - 22nd International Conference on Advanced Information Networking and Applications Workshops/Symposia, AINA 2008, 10.1109/WAINA.2008.180, 1534-1539, 2008.09, The vulnerabilities, e.g., DoS attack or dictionary attack, are shown in 4-Way Handshake which is the rekey protocol used in Wireless LAN security standard IEEE 802.11i. And the countermeasures against these are already proposed. In this paper, we propose key distribution scheme using matched filter. This paper shows that our proposal improves the resistance against DoS attack with less computational overhead compared with previous approaches, and is also effective against dictionary attack..
187. Ryuzou Nishi, Yoshiaki Hori, Kouichi Sakurai, Reliable key distribution scheme for lossy channels, IEICE Transactions on Information and Systems, 10.1093/ietisy/e91-d.5.1485, E91-D, 5, 1485-1488, 2008.05, We address reliable key distribution scheme for lossy channels such as wireless or power line. In the key distribution over these lossy channels, if key information is lost, there is critical issue that the subsequent communication is disabled. In this paper, we show that our proposal has more reliable property than the related works and has the reliable property equivalent to the dedicated communication channels such as Ethernet..
188. Yu Feng Wang, Yoshiaki Hori, Kouichi Sakurai, Characterizing economic and social properties of trust and reputation systems in P2P environment, Journal of Computer Science and Technology, 10.1007/s11390-008-9118-y, 23, 1, 129-140, 2008.01, Considering the fact that P2P (Peer-to-Peer) systems are self-organized and autonomous, social-control mechanism (like trust and reputation) is essential to evaluate the trustworthiness of participating peers and to combat the selfish, dishonest and malicious peer behaviors. So, naturally, we advocate that P2P systems that gradually act as an important information infrastructure should be multi-disciplinary research topic, and reflect certain features of our society. So, from economic and social perspective, this paper designs the incentive-compatible reputation feedback scheme based on well-known economic model, and characterizes the social features of trust network in terms of efficiency and cost. Specifically, our framework has two distinctive purposes: first, from high-level perspective, we argue trust system is a special kind of social network, and an accurate characterization of the structural properties of the network can be of fundamental importance to understand the dynamics of the system. Thus, inspired by the concept of weighted small-world, this paper proposes new measurements to characterize the social properties of trust system, that is, high global and local efficiency, and low cost; then, from relative low-level perspective, we argue that reputation feedback is a special kind of information, and it is not free. So, based on economic model, VCG (Vickrey-Clarke-Grove)-like reputation remuneration mechanism is proposed to stimulate rational peers not only to provide reputation feedback, but truthfully offer feedback. Furthermore, considering that trust and reputation is subjective, we classify the trust into functional trust and referral trust, and extend the referral trust to include two factors: similarity and truthfulness, which can efficiently reduce the trust inference error. The preliminary simulation results show the benefits of our proposal and the emergence of certain social properties in trust network..
189. Erwan Le Malécot, Masayoshi Kohara, Yoshiaki Hori, Kouichi Sakurai, Toward a scalable visualization system for network traffic monitoring, IEICE Transactions on Information and Systems, 10.1093/ietisy/e91-d.5.1300, E91-D, 5, 1300-1310, 2008.01, With the multiplication of attacks against computer networks, system administrators are required to monitor carefully the traffic exchanged by the networks they manage. However, that monitoring task is increasingly laborious because of the augmentation of the amount of data to analyze. And that trend is going to intensify with the explosion of the number of devices connected to computer networks along with the global rise of the available network bandwidth. So system administrators now heavily rely on automated tools to assist them and simplify the analysis of the data. Yet, these tools provide limited support and, most of the time, require highly skilled operators. Recently, some research teams have started to study the application of visualization techniques to the analysis of network traffic data. We believe that this original approach can also allow system administrators to deal with the large amount of data they have to process. In this paper, we introduce a tool for network traffic monitoring using visualization techniques that we developed in order to assist the system administrators of our corporate network. We explain how we designed the tool and some of the choices we made regarding the visualization techniques to use. The resulting tool proposes two linked representations of the network traffic and activity, one in 2D and the other in 3D. As 2D and 3D visualization techniques have different assets, we resulted in combining them in our tool to take advantage of their complementarity. We finally tested our tool in order to evaluate the accuracy of our approach..
190. Chunhua Su, Kouichi Sakurai, A distributed privacy-preserving association rules mining scheme using frequent-pattern tree, 4th International Conference on Advanced Data Mining and Applications, ADMA 2008 Advanced Data Mining and Applications - 4th International Conference, ADMA 2008, Proceedings, 10.1007/978-3-540-88192-6-17, 5139 LNAI, 170-181, 2008, Association rules mining is a frequently used technique which finds interesting association and correlation relationships among large set of data items which occur frequently together. Nowadays, data collection is ubiquitous in social and business areas. Many companies and organizations want to do the collaborative association rules mining to get the joint benefits. However, the sensitive information leakage is a problem we have to solve and privacy-preserving techniques are strongly needed. In this paper, we focus on the privacy issue of the association rules mining and propose a secure frequent-pattern tree (FP-tree) based scheme to preserve private information while doing the collaborative association rules mining. We show that our scheme is secure and collusion-resistant for n parties, which means that even if n - 1 dishonest parties collude with a dishonest data miner in an attempt to learn the associations rules between honest respondents and their responses, they will be unable to success..
191. Chunhua Su, Feng Bao, Jianying Zhou, Tsuyoshi Takagi, Kouichi Sakurai, A new scheme for distributed density estimation based privacy-preserving clustering, 3rd International Conference on Availability, Security, and Reliability, ARES 2008 ARES 2008 - 3rd International Conference on Availability, Security, and Reliability, Proceedings, 10.1109/ARES.2008.129, 112-119, 2008, The sensitive information leakage and security risk is a problem from which both individual and enterprise suffer in massive data collection and the information retrieval by the distrusted parties. In this paper, we focus on the privacy issue of data clustering and point out some security risks in the existing data mining algorithms. Associated with cryptographic techniques, we initiate an application of random data perturbation (RDP) which has been widely used for preserving the privacy of individual records in statistical database for the distributed data clustering scheme. Our scheme applies linear transformation of Gaussian distribution perturbed data and general additional data perturbation (GADP) schemes to preserve the privacy for distributed kernel density estimation with the help of any trusted third party. We also show that our scheme is more secure against the random matrix-based filtering attack which is based on analysis of the distribution of the eigenvalues by using two RDP methods..
192. Tai Hoon Kim, Kouichi Sakurai, A study on security level management model description, International Journal of Multimedia and Ubiquitous Engineering, 3, 1, 87-94, 2008, Security level decision is a basic activity for developing and managing of safe information systems, and core factor which can affect the investment for security countermeasures. According to the security level of IS, where and how the security countermeasures are implemented, which security policies are selected, and who will manage them are able to be decided. But more important thing than level decision is the management of level decided. And in this model, we proposed a new model to manage security level of IS..
193. Kenji Imamoto, Jianying Zhou, Kouichi Sakurai, Achieving evenhandedness in certified email system for contract signing, International Journal of Information Security, 10.1007/s10207-008-0056-z, 7, 6, 383-394, 2008, Certified email is a system which enables a sender to prove a receiver's receipt of email. Such a system can be used for applications related to electronic commerce on the Internet. This paper considers a situation where a sender or a receiver wants to change his/her mind due to the change of mail content value (e.g., stock, auction, gambling) during the transaction. We point out that no traditional certified email systems have been designed for such a case, thus one of the participants can be at a disadvantage. To avoid this problem, we propose an evenhanded certified email system in which each participant can change his/her choice, either cancel or finish the transaction, at any time during the transaction..
194. Yasufumi Hashimoto, Tsuyoshi Takagi, Kouichi Sakurai, General fault attacks on multivariate public key cryptosystems, 4th International Workshop on Post-Quantum Cryptography, PQCrypto 2011 Post-Quantum Cryptography - 4th International Workshop, PQCrypto 2011, Proceedings, 10.1007/978-3-642-25405-5_1, 7071 LNCS, 1-18, 2011.12, The multivariate public key cryptosystem (MPKC), which is based on the problem of solving a set of multivariate systems of quadratic equations over a finite field, is expected to be secure against quantum attacks. Although there are several existing schemes in MPKC that survived known attacks and are much faster than RSA and ECC, there have been few discussions on security against physical attacks, aside from the work of Okeya et al. (2005) on side-channel attacks against Sflash. In this study, we describe general fault attacks on MPKCs including Big Field type (e.g. Matsumoto-Imai, HFE and Sflash) and Stepwise Triangular System (STS) type (e.g. UOV, Rainbow and TTM/TTS). For both types, recovering (parts of) the secret keys S,T with our fault attacks becomes more efficient than doing without them. Especially, on the Big Field type, only single fault is sufficient to recover the secret keys..
195. Yoshiro Fukushima, Yoshiaki Hori, Kouichi Sakurai, Proactive blacklisting for malicious web sites by reputation evaluation based on domain and IP address registration, 10th IEEE Int. Conf. on Trust, Security and Privacy in Computing and Communications, TrustCom 2011, 8th IEEE Int. Conf. on Embedded Software and Systems, ICESS 2011, 6th Int. Conf. on Frontier of Computer Science and Technology, FCST 2011 Proc. 10th IEEE Int. Conf. on Trust, Security and Privacy in Computing and Communications, TrustCom 2011, 8th IEEE Int. Conf. on Embedded Software and Systems, ICESS 2011, 6th Int. Conf. FCST 2011, 10.1109/TrustCom.2011.46, 352-361, 2011.12, The objective of creating malicious software (i.e., malware), intruding computers and conducting malicious activities is shifted from showing off attacker's computer skills to earning money. Thus, recent attackers take more sophisticated and effective malware infection ways such as malware infection via malicious Web sites as well as the traditional exploitations like worm propagation. The malicious Web sites attempt to compromise machines by drive-by-download attack which redirects users to exploiting sites and install malware compulsorily in their machines by exploiting vulnerabilities of their Web browser or plugins. As a countermeasure for these malicious Web sites, blacklisting URLs or domains of them is significant. However, attackers tend to change the URLs or domains in a short period to avoid the blacklist. Thus, a blacklisting scheme which can filter even unknown malicious Web sites is critical. In this paper, we first analyze characteristics of malicious Web sites by their domain information such as AS (Autonomous System), IP address block, IP address, domain, and registrar. Second, we evaluate reputations of IP address blocks and registrars used by attackers. Then, we propose a blacklisting scheme constructed of the combination of IP address block and registrars with low reputation, that is, intensively used by attackers. From our experimental results, the Web sites with the same combination with low reputation appeared over long period, which indicates that our proposed blacklist has a certain capability of filtering unknown malicious Web sites..
196. Amril Syalim, Takashi Nishide, Kouichi Sakurai, Realizing proxy re-encryption in the symmetric world, International Conference on Informatics Engineering and Information Science, ICIEIS 2011 Informatics Engineering and Information Science - International Conference, ICIEIS 2011, Proceeding, 10.1007/978-3-642-25327-0_23, 251 CCIS, 259-274, 2011.12, Proxy re-encryption is a useful concept and many proxy re-encryption schemes have been proposed in the asymmetric encryption setting. In the asymmetric encryption setting, proxy re-encryption can be beautifully implemented because many operations are available to directly transform a cipher to another cipher without the proxy needs to access the plaintexts. However, in many situations, for a better performance, the data is encrypted using symmetric ciphers. Most symmetric ciphers do not support proxy cryptography because of malleability (that is needed to implement the proxy re-encryption) is not a desired property in a secure encryption scheme. In this paper, we suggest an idea to implement a pure proxy re-encryption for the symmetric ciphers by first transforming the plaintext into a random sequence of blocks using an All or nothing transform (AONT). We show an example of the proxy re-encryption scheme using a weak encryption (i.e. simple permutation) that has a simple conversion function to convert a permutation to another. The encryption scheme exploits three characteristics of an AONT transformation: (1) the output of an AONT is a pseudorandom, (2) the output of an AONT cannot be transformed back if any parts is missing, and (3) the output of an AONT cannot be transformed back without having all blocks with correct position. We show security argument of the proposed scheme and its performance evaluation..
197. Takashi Nishide, Kouichi Sakurai, Security of offline anonymous electronic cash systems against insider attacks by untrusted authorities revisited, 3rd IEEE International Conference on Intelligent Networking and CollaborativeSystems, INCoS 2011 Proceedings - 3rd IEEE International Conference on Intelligent Networking and Collaborative Systems, INCoS 2011, 10.1109/INCoS.2011.146, 656-661, 2011.12, In the design of electronic cash systems, we usually focus on preventing customers' malicious behaviors. However, since authorities such as banks and certificate authorities may have important secret data of customers, the insider attacks by the untrusted authorities also need to be handled carefully. Miyazaki and Sakurai [1] first evaluated security of offline anonymous electronic cash systems against the insider attacks by untrusted authorities. They analyzed the security of the existing electronic cash systems and categorized the systems into four types. In this paper, we reconsider the security of offline anonymous electronic cash systems including more recent systems based on the classification of Miyazaki and Sakurai..
198. Yoshiaki Hori, Takashi Nishide, Kouichi Sakurai, Towards countermeasure of insider threat in network security, 3rd IEEE International Conference on Intelligent Networking and CollaborativeSystems, INCoS 2011 Proceedings - 3rd IEEE International Conference on Intelligent Networking and Collaborative Systems, INCoS 2011, 10.1109/INCoS.2011.156, 634-636, 2011.12, We discuss countermeasure against insider threats in network security aspect. In the context of countermeasure against insider threats, there is no perimeter for access control in a network and a traditional process by using a firewall on a perimeter are not suitable. We show a mechanism of countermeasure against insider threats in network security for countermeasure technically and legally..
199. Dong Hao, Yizhi Ren, Kouichi Sakurai, A game theory-based surveillance mechanism against suspicious insiders in MANETs (work-in-progress), 2nd International Conference on Trusted Systems, INTRUST 2010 Trusted Systems - Second International Conference, INTRUST 2010, Revised Selected Papers, 10.1007/978-3-642-25283-9_16, 6802 LNCS, 237-252, 2011.11, One of the most challenging issues in Mobile Ad-Hoc Network (MANET) is that the insiders are untrustworthy in packet forwarding stage. All the nodes which loss data-packets over a preset threshold can be generalized as Suspicious Insiders. To intimidate these suspicious insiders and reduce packet dropping, surveillance is the most direct and easiest method. In this paper, we propose a novel surveillance mechanism to monitor the packet dropping of suspicious insiders. On one hand, our work provides the monitor with optimal strategies which will maximize its long term utility; On the other hand, our work presents an on-demand monitoring scheme which will balance the tradeoff between security and resource consumption. First, we utilize a reputation scheme to distinguish suspicious insiders from legitimate members, and quantify the threat level of the suspicious insiders. Then taking into consideration security and resource consumption, we utilize game theory to analyze the interaction between monitor and suspicious insider. Finally, optimal mixed-strategy is computed to identify the best way for the monitor to respond to the suspicious insider..
200. Liangjian Mao, Shuzhen Yao, Kai Zhang, Kouichi Sakurai, Design and implementation of document access control model based on role and security policy, 2nd International Conference on Trusted Systems, INTRUST 2010 Trusted Systems - Second International Conference, INTRUST 2010, Revised Selected Papers, 10.1007/978-3-642-25283-9_2, 6802 LNCS, 26-36, 2011.11, To design a method of document access control with flexibility, generality and fine-granularity, we establish a document access control model, which is an abstract description for general scene of document access. Security policies are presented to describe security constraints, so as to meet security requirements of this model. In order to demonstrate the theories and strategies more intuitively, we design a prototype system of document access control based on XACML-RBAC framework to verify the validity of model and algorithms and the feasibility of mechanism. It realizes the authorization protection of the standard OFFICE documents..
201. Ilsun You, Yoshiaki Hori, Kouichi Sakurai, Enhancing SVO logic for mobile IPv6 security protocols, Journal of Wireless Mobile Networks, Ubiquitous Computing, and Dependable Applications, 2, 3, 26-52, 2011.09, In order to protect Mobile Internet Protocol Version 6 (MIPv6), considerable researches have been made, consequently followed by various security protocols, which are based on public key cryptography. Especially, depending on a proper address based public key method, these protocols use each node's address as a public key certificate to authenticate its public key because no global public key infrastructure is available in MIPv6 environments. In addition, they execute an appropriate address test to check if a node exists at its claimed address. With such security features, the protocols prevent critical attacks including redirect, man-in-the middle, and denial of service ones. On the other hand, it is clearly of paramount importance to formally evaluate the MIPv6 security protocols to design them without flaws. Unfortunately, there is lack of the formal verification method to precisely reason about their correctness while considering their unique security properties to our best knowledge. In this paper, we propose an extended SVO logic for the thorough verification of the MIPv6 security protocols. Then, we show its effectiveness by applying the proposed logic to four security protocols..
202. Chul Sur, Youngho Park, Takashi Nishide, Kouichi Sakurai, Kyung Hyune Rhee, Securing location-aware services based on online/offline signatures in VANETs, IFIP WG 8.4/8.9 International Cross Domain Conference and Workshop on Availability, Reliability and Security for Business, Enterprise and Health Information Systems, ARES 2011 Availability, Reliability and Security for Business, Enterprise and Health Information Systems - IFIP WG 8.4/8.9 International Cross Domain Conference and Workshop, ARES 2011, Proceedings, 10.1007/978-3-642-23300-5_21, 271-285, 2011.09, In this paper, we propose a novel privacy-preserving location assurance protocol for secure location-aware services over vehicular ad hoc networks (VANETs). In particular, we introduce the notion of location-aware credentials based on "hash-sign-switch" paradigm so as to guarantee the trustworthiness of location in location-aware services while providing conditional privacy preservation which is a desirable property for secure vehicular communications. Furthermore, the proposed protocol provides efficient procedures that alleviate a burden of computation for location-aware signature generation and verification on vehicles in VANETs. In order to achieve these goals, we consider online/offline signature scheme and identity-based aggregate signature scheme as our building blocks. Finally, we demonstrate experimental results to confirm the efficiency and effectiveness of the proposed protocol..
203. Kazuhide Fukushima, Shinsaku Kiyomoto, Yutaka Miyake, Kouichi Sakurai, Towards optimal revocation and tracing schemes - The power of the ternary tree, International Conference on Security and Cryptography, SECRYPT 2011 SECRYPT 2011 - Proceedings of the International Conference on Security and Cryptography, 37-49, 2011.09, Digital content distribution services require that 1) only valid user devices that has a valid key can decrypt the broadcasting content, 2) the keys can no longer be used to decrypt the content, if keys in a device are revealed, and 3) invalid users who illegally use keys in a device can be identified. This paper proposes a broadcast encryption scheme with traitor tracing based on the ternary tree structure. We design a new cover-finding algorithm and label assignment algorithm in order to achieve a coalition-resistant revocation and tracing schemes. In our scheme, the number of labels stored in a client device can be reduced by about 20.4 percent and the average header length by up to 15.0 percent in the case where the total number of devices is 65,536. The efficiency of the traitor tracing is the same as the complete subtree method, and its computational cost imposed on a client device stays within O(logn). Our scheme is an improvement of the complete subtree and difference subset methods..
204. Seiichiro Mizoguchi, Keisuke Takemori, Yutaka Miyake, Yoshiaki Hori, Kouichi Sakurai, Traceback framework against botmaster by sharing network communication pattern information, 2011 5th International Conference on Innovative Mobile and Internet Services in Ubiquitous Computing, IMIS 2011 Proceedings - 2011 5th International Conference on Innovative Mobile and Internet Services in Ubiquitous Computing, IMIS 2011, 10.1109/IMIS.2011.152, 639-644, 2011.09, In order to exterminate a botnet, we have to trace a botnet and arrest its botmaster. In this paper, we make a model of communication pattern of a C&C server that sends/receives packets to/from the botmaster. Then we discuss how botmaster trace back can be achieved. We describe which communication patterns we should focus on to find the botmaster or upper C&C servers. Furthermore, we propose a framework for botmaster trace back. In this framework, owners of servers which become to C&C server will collaborate and share the communication patterns for trace back. To do this, we propose the information sharing using communication pattern monitoring tools with the servers..
205. Xiaojuan Liao, Dong Hao, Kouichi Sakurai, Using game theory to classify wireless Ad Hoc network attacks with analysis on countermeasures, International Journal of Advancements in Computing Technology, 10.4156/ijact.vol3.issue8.35, 3, 8, 296-303, 2011.09, Game theory has been receiving immense concern to deal with attacks in wireless ad hoc networks, which are widely employed in a large range of applications but vulnerable to various attacks. Previous works provided readers with comprehensive understanding of game theoretic solutions on cyber security problems. However, they neglect the relationship between attack characteristics and the corresponding game features. In this paper, we study the application of game theory on attacks in wireless ad hoc networks. Specifically, we present a classification which associates attack characteristics with types of game players and then examine the relationship between attack scenarios and types of corresponding game models. By illustrating the different players and game types in a variety of game theoretic approaches, we provide a comprehensive view on game based solutions to attacks in wireless ad hoc networks..
206. Jingyu Hua, Kouichi Sakurai, A SMS-based mobile botnet using flooding algorithm, 5th Workshop in Information Security Theory and Practice, WISTP 2011 Information Security Theory and Practice Security and Privacy of Mobile Devices in Wireless Communication - 5th IFIP WG 11.2 International Workshop, WISTP 2011, Proceedings, 10.1007/978-3-642-21040-2_19, 264-279, 2011.06, As a lot of sophisticated duties are being migrated to mobile phones, they are gradually becoming hot targets of hackers. Actually, during the past few years, It has appeared many malware targeting mobile phones and the situation is getting worse. Under this circumstance, we may ask a serious question: whether can those infected phones be organized to a botnet? In this paper, we present a design of such a botnet using Short Message Service (SMS) as its Command and Control (C&C) medium. We cover all the aspects of the botnet design including the stealthiness protection, the topology selecting and the botnet maintaining. Our simulations show that in our proposed SMS-based botnet a newly issued C&C message can be covertly propagated to over 90% of the total 20000 bots within 20 minutes based on a simple flooding algorithm. Moreover, in this process each bot sends no more than four SMS messages and the botnet is robust to both random and selective node failures. Thereby, we demonstrate that the proposed mobile botnet is indeed a serious threat on the security of the mobile computing environment. For this reason, we further explore several effective defense strategies against such a botnet. In doing so, we hope to be one step ahead of the hackers to discover and prevent this upcoming threat..
207. Laiping Zhao, Yizhi Ren, Kouichi Sakurai, A resource minimizing scheduling algorithm with ensuring the deadline and reliability in heterogeneous systems, 25th IEEE International Conference on Advanced Information Networking and Applications, AINA 2011 Proceedings - 25th IEEE International Conference on Advanced Information Networking and Applications, AINA 2011, 10.1109/AINA.2011.87, 275-282, 2011.06, The distributed system made the large-scale scientific computing possible in a cost effective way. And the hardware resources in such systems are also getting much cheaper than years before. However, the problem of executing the job using minimum resources is still reasonable and important, especially for the cloud environment, who has to save energy and control cost. Unfortunately, only a few existing scheduling algorithms have taken into account the resource usage issue. In this study, with considering the realistic network topology and communication model, we firstly propose the Deadline, Reliability, Resources-aware (DRR) scheduling algorithm. The theory analysis fully demonstrate that, the output schedule of our algorithm can satisfy the user's requirement on reliability and deadline. Through the experiments, with setting the deadline less than the makespan of the MaxRe algorithm's output schedule, we find that our algorithm can complete the job under this deadline. Besides, our algorithm can save almost 50% computation resources and 70% communication resources than FTSA(bl) and FTSA(tl+bl) [3] algorithms..
208. Peng Gao, Takashi Nishide, Yoshiaki Hori, Kouichi Sakurai, Integrity for the In-flight web page based on a fragile watermarking chain scheme, 5th International Conference on Ubiquitous Information Management and Communication, ICUIMC 2011 Proceedings of the 5th International Conference on Ubiquitous Information Management and Communication, ICUIMC 2011, 10.1145/1968613.1968715, 2011.05, In recent years, it has been found that middle modifications and attacks widely exist when web pages are transferred from a web server to a user via HTTP. And the reason is that HTTP does not guarantee the integrity of network traffic. This paper presents a protocol which enforces integrity protection in web page against the so called In-flight page change by using a novel fragile watermarking chain scheme. The protocol not only can have a better performance than HTTPS by supporting the web cache technology, but also save the communication bandwidth and storage space of the web server. Furthermore, it can locate the unauthorized modification of HTML code more precisely than existing solutions..
209. Fangming Zhao, Takashi Nishide, Kouichi Sakurai, Realizing fine-grained and flexible access control to outsourced data with attribute-based cryptosystems, 7th International Conference on Information Security Practice and Experience, ISPEC 2011 Information Security Practice and Experience - 7th International Conference, ISPEC 2011, Proceedings, 10.1007/978-3-642-21031-0_7, 6672 LNCS, 83-97, 2011.05, We consider the problem of constructing a secure cloud storage service to which users outsource sensitive data for sharing with others where, in particular, the service provider is not completely trusted by the customer. Cloud storage service denotes an architectural shift toward thin clients and conveniently centralized provision of both computing and storage resources. When utilizing cloud storage for secure data sharing, one of the main motivating problems of this architecture is providing thin clients with both strong data confidentiality and flexible fine-grained access control without imposing additional cost on them (clients). To achieve this goal, we propose a novel data sharing protocol by combining and exploiting two of the latest attribute based cryptographic techniques, attribute-based encryption (ABE) and attribute-based signature (ABS). Furthermore, we also give a detailed comparison of our scheme with several latest existing schemes..
210. Christian W. Probst, Ilsun You, Dongwan Shin, Kouichi Sakurai, Guest editorial
Addressing insider threats and information leakage, Journal of Wireless Mobile Networks, Ubiquitous Computing, and Dependable Applications, 2, 1, 1-3, 2011.03.
211. Ilsun You, Yoshiaki Hori, Kouichi Sakurai, Towards formal analysis of wireless LAN security with MIS protocol, International Journal of Ad Hoc and Ubiquitous Computing, 10.1504/IJAHUC.2011.038997, 7, 2, 112-120, 2011.03, In 2004, the MIS and MISAUTH protocols (shortly MISP) were proposed for secure and fast connection in Wireless LAN (WLAN). Since then, several studies were conducted to evaluate MISP. However, because of the lack of formal security analysis, the security measures provided by them cannot be trusted to be precise and reasonable. Motivated by this, we formally analyse MISP based on both BAN-logic and the Automated Validation of Internet Security Protocols and Applications (AVISPAS) tool. This analysis clearly shows that MISP suffers from weak Session Key (SK) while being vulnerable to Denial of Service (DoS) attack. We discuss these weaknesses and related attacks in detail, and also provide considerable comments for implementation of MISP..
212. Liang Zhao, Avishek Adhikari, Kouichi Sakurai, A New Scrambling Evaluation Scheme Based on Spatial Distribution Entropy and Centroid Difference of Bit-Plane, 9th International Workshop on Digital Watermarking, IWDW 2010 Digital Watermarking - 9th International Workshop, IWDW 2010, Revised Selected Papers, 10.1007/978-3-642-18405-5_4, 29-44, 2011.01, Watermarking is one of the most effective techniques for copyright protection and information hiding. It can be applied in many fields of our society. Nowadays, some image scrambling schemes are used as one part of the watermarking algorithm to enhance the security. Therefore, how to select an image scrambling scheme and what kind of the image scrambling scheme may be used for watermarking are the key problems. Evaluation method of the image scrambling schemes can be seen as a useful test tool for showing the property or flaw of the image scrambling method. In this paper, a new scrambling evaluation system based on spatial distribution entropy and centroid difference of bit-plane is presented to obtain the scrambling degree of image scrambling schemes. Our scheme is illustrated and justified through computer simulations. The experimental results show (in Figs. 6 and 7) that for the general gray-scale image, the evaluation degree of the corresponding cipher image for the first 4 significant bit-planes selection is nearly the same as that for the 8 bit-planes selection. That is why, instead of taking 8 bit-planes of a gray-scale image, it is sufficient to take only the first 4 significant bit-planes for the experiment to find the scrambling degree. This 50% reduction in the computational cost makes our scheme efficient..
213. Liang Zhao, Avishek Adhikari, Di Xiao, Kouichi Sakurai, Cryptanalysis on an Image Scrambling Encryption Scheme Based on Pixel Bit, 9th International Workshop on Digital Watermarking, IWDW 2010 Digital Watermarking - 9th International Workshop, IWDW 2010, Revised Selected Papers, 10.1007/978-3-642-18405-5_5, 45-59, 2011.01, Recently, an image scrambling encryption algorithm which makes use of one-dimensional chaos system for shuffling the pixel bits was proposed in [G.-D. Ye, Pattern Recognition Lett. 31(2010) 347-354]. Through the scrambling algorithm, the pixel locations and values can be encrypted at the same time. This scheme can be thought of as a typical binary image scrambling encryption considering the bit-plain of size (formula presented). In [Li C.Q., Lo K. T., http://arxiv.org/PS_cache/arxiv/pdf/0912/0912.1918v2.pdf], Li et al. proposed an attack using more than ⌈log 2(formula presented)⌉ many known-plaintext images to recover the original plain image with the noise of size M ×N. The same principle is also suitable for the chosen-plaintext attack which can obtain the exact plain image. In the current paper, a simple attack on the original scheme is presented by applying chosen-plaintext images. Using our attack, the encryption vectors (formula presented) and (formula presented) and the decryption vectors TM′ and TN′ can be recovered completely. The experimental simulations on two standard images of size 128 ×128 and 256 ×256 justify our analysis. It is shown that the recovered images are identical with the corresponding original images. For both the original images, the number of chosen-plaintext images required in our scheme is 9, where as to do the same using the scheme proposed in Li et al.’ attack, at least 17 and 19 chosen-plaintext images there will be required respectively. Moreover, the some method can be also used for chosen-ciphertext attack which reveals the decryption vectors TM′ and TN′ directly. Note that our attacks are also successful under iteration system which is remarked in the conclusions..
214. Takashi Nishide, Kouichi Sakurai, Distributed Paillier Cryptosystem without Trusted Dealer, 11th International Workshop on Information Security Applications, WISA 2010 Information Security Applications - 11th International Workshop, WISA 2010, Revised Selected Papers, 10.1007/978-3-642-17955-6_4, 44-60, 2011.01, We propose a distributed key generation protocol for the threshold Paillier cryptosystem. Often in the multiparty computation based on the threshold Paillier cryptosystem, the existence of a trusted dealer is assumed to distribute secret key shares, but it can be a single point of attack, so it is not preferable. Building on the threshold Paillier cryptosystem with a trusted dealer, we show how to eliminate the trusted dealer by robust distributed key generation without using safe primes..
215. Jingyu Hua, Mingchu Li, Yizhi Ren, Kouichi Sakurai, Efficient context-sensitive intrusion detection based on state transition table, IEICE Transactions on Fundamentals of Electronics, Communications and Computer Sciences, 10.1587/transfun.E94.A.255, E94-A, 1, 255-264, 2011.01, Those host-based intrusion detection models like VPStatic first construct a model of acceptable behaviors for each monitored program via static analysis, and then perform intrusion detection by comparing them with programs' runtime behaviors. These models usually share the highly desirable feature that they do not produce false alarms but face the conflicts between accuracy and efficiency. For instance, the high accuracy of the VP- Static model is at the cost of high space complexity. In this paper, we use a statically-constructed state transition table (SiT), which records expected transitions among system calls as well as their stack states (return address lists), as a behavior model to perform context-sensitive intrusion detection. According to our analysis, our STE model improves the space efficiency of the VPStatic model without decreasing its high precision and time effi ciency. Experiments show that for three test programs, memory uses of our STE models are all much less than half of the VPStatic models'. Thereby, we alleviate the conflicts between the accuracy and the efficiency..
216. Ilsun You, Jong Hyouk Lee, Yoshiaki Hori, Kouichi Sakurai, Enhancing MISP with fast mobile IPv6 security, Mobile Information Systems, 10.3233/MIS-2011-0121, 7, 3, 271-283, 2011.01, The Mobile Broadband Association has developed the MIS and MISAUTH protocols as link-layer fast authentication protocols. A combination of MIS and MISAUTH protocols, called as MISP, provides secure and fast connection for a wireless access network, but it has been reported that MISP creates a weak session key and suffers from a denial-of-service attack. In addition, a transaction with an authentication server that is required for every authentication is considered as a delay factor during handovers. In this paper, we present an improvement of MISP that utilizes the fast handover approach of Fast Mobile IPv6 and minimizes an involvement of the authentication server while eliminating identified security drawbacks of MISP. The formal security analysis is performed to verify the correctness of the proposed scheme. Moreover, the handover performance of the proposed scheme is compared with an existing scheme..
217. Ruan Na, Yizhi Ren, Yoshiaki Hori, Kouichi Sakurai, A generic evaluation method for key management schemes in wireless sensor network, 5th International Conference on Ubiquitous Information Management and Communication, ICUIMC 2011 Proceedings of the 5th International Conference on Ubiquitous Information Management and Communication, ICUIMC 2011, 10.1145/1968613.1968680, 2011, Wireless sensor networks (WSN) have been widely used in various applications. Since their sensor nodes are resource-constrained, key management is one of the most challenging issues in design of WSN. Currently, various efficient lightweight key management schemes have been proposed to enable encryption and authentication in WSN for different application scenarios. According to different requirements, it is important to select the trustworthy key management schemes in a WSN for setting up a fully trusted WSN mechanism. In this context, adaptive methods are required to evaluate those schemes. In this paper, we exploit Analytic Hierarchy Process (AHP) to help with the complex decision. Specifically, we consider the following performance criteria: scalability, key connectivity, resilience, storage overhead, processing overhead and communication overhead. Our method is able help choosing a suitable scheme for given requirements..
218. Liang Zhao, Avishek Adhikari, Kouichi Sakurai, A new scrambling evaluation scheme based on spatial distribution entropy and centroid difference of bit-plane, 9th International Workshop on Digital Watermarking, IWDW 2010 Digital Watermarking - 9th International Workshop, IWDW 2010, Revised Selected Papers, 10.1007/978-3-642-18405-5-4, 6526 LNCS, 29-44, 2011, Watermarking is one of the most effective techniques for copyright protection and information hiding. It can be applied in many fields of our society. Nowadays, some image scrambling schemes are used as one part of the watermarking algorithm to enhance the security. Therefore, how to select an image scrambling scheme and what kind of the image scrambling scheme may be used for watermarking are the key problems. Evaluation method of the image scrambling schemes can be seen as a useful test tool for showing the property or flaw of the image scrambling method. In this paper, a new scrambling evaluation system based on spatial distribution entropy and centroid difference of bit-plane is presented to obtain the scrambling degree of image scrambling schemes. Our scheme is illustrated and justified through computer simulations. The experimental results show (in Figs. 6 and 7) that for the general gray-scale image, the evaluation degree of the corresponding cipher image for the first 4 significant bit-planes selection is nearly the same as that for the 8 bit-planes selection. That is why, instead of taking 8 bit-planes of a gray-scale image, it is sufficient to take only the first 4 significant bit-planes for the experiment to find the scrambling degree. This 50% reduction in the computational cost makes our scheme efficient..
219. Rong Huang, Kouichi Sakurai, A robust and compression-combined digital image encryption method based on compressive sensing, 7th International Conference on Intelligent Information Hiding and Multimedia Signal Processing, IIHMSP 2011 Proceedings - 7th International Conference on Intelligent Information Hiding and Multimedia Signal Processing, IIHMSP 2011, 10.1109/IIHMSP.2011.53, 105-108, 2011, This paper proposes a compression-combined digital image encryption method which is robust against consecutive packet loss and malicious shear attack. We utilize the characteristics of compressive sensing, dimensional reduction and random projection, to compress and encrypt a digital image simultaneously. On this basis, block Arnold scrambling is used to permutate the position of measurements. Bit wise XOR operation is executed on the quantized binary bit stream to dissipate the Gaussian distribution property of cipher image. In this paper, one dimensional Logistic mapping is used to generate chaotic sequences, which will be regarded as the parameters of block Arnold transformation and the pseudo-random sequence for XOR operation. Numerical experiments show that the cipher image has following features, robustness, low data volume, incoherence, key sensitivity, and resistance to brute force attack..
220. Fumiharu Etoh, Yoshiaki Hori, Kouichi Sakurai, A study of communication route selection considering route security, 11th IEEE/IPSJ International Symposium on Applications and the Internet, SAINT 2011 Proceedings - 11th IEEE/IPSJ International Symposium on Applications and the Internet, SAINT 2011, 10.1109/SAINT.2011.69, 360-365, 2011, Networks such as the Internet and mobile phone networks are widely used. Existing telecommunication route selection is based on the transmission quality, such as bandwidth, delay, costs, and network obstacles when routing is requested. However, the security level of the selected route has not traditionally been a priority when selecting a route. In this paper, we propose a method of selecting a communication route for secure communications by evaluating the security of the route. For the security evaluation of the route, we define both metrics and measurements. It is possible to evaluate the security level of a route by recognizing how the level changes after measuring certain metrics. Furthermore, we propose metrics and measurement based on the Common Criteria..
221. Xiaojuan Liao, Dong Hao, Kouichi Sakurai, Achieving cooperative detection against Sybil attack in wireless ad hoc networks
A game theoretic approach, 17th Asia Pacific Conference on Communications, APCC 2011 17th Asia Pacific Conference on Communications, APCC 2011, 10.1109/APCC.2011.6152918, 806-811, 2011, Sybil Attack means one node counterfeits multiple identities. It poses great threats to the routing of wireless ad hoc networks. Many existing solutions employ local detection method to capture misbehavior and then enhance the detection accuracy by information exchange. However, they ignore the rationality of member nodes. To save resource, rational nodes are reluctant to share information, therefore, how to guarantee reliable information exchange becomes a challenge issue. This paper presents a cooperative detection method against Sybil attack. Our method adopts the reputation mechanism which relies on the observation exchange to differentiate Sybil identities from legitimate ones. To promote the observation exchange, we present a cooperative detection game with initial condition, which helps nodes be aware that with which to share the observations can bring the maximum utilities. The theoretical and numerical analysis indicate that only benign and unselfish nodes can be accepted by their rational neighbors while Sybil nodes are excluded from the information exchange..
222. Rimba Whidiana Ciptasari, Aulia Fajar, Fazmah Arif Yulianto, Kouichi Sakurai, An efficient key generation method in audio zero-watermarking, 7th International Conference on Intelligent Information Hiding and Multimedia Signal Processing, IIHMSP 2011 Proceedings - 7th International Conference on Intelligent Information Hiding and Multimedia Signal Processing, IIHMSP 2011, 10.1109/IIHMSP.2011.63, 336-339, 2011, This paper proposes modification of previous audio zero-watermarking, proposed by Chen et. al [1], in terms of its watermark-key generation. We investigate that the size of previous watermark detection key is around two or three times larger than its watermark data. In order to yield an efficient key rather than generating three secret keys, we will exploit data indices, instead of field indices, to store the key. Compared to previous method, our watermark key's size is relatively the same as its watermark data. Despite of having smaller key size, the experiment demonstrates that our scheme has maximum imperceptibility level, indicated by SNR value, and can resist to several non-malicious attacks, such as echo addition, band pass filtering and re-sampling. In addition, we also address the invertibility and quasi-invertibility of our scheme for resolving rightful ownership, and present attack which can cause confusion to rightful claim. We list the objective of attacks, abilities of attacker, and a scenario to evaluate its security. According to the experimental result, our proposed scheme still remains several limitations, regardless of certification authority existence..
223. Xiaojuan Liao, Dong Hao, Kouichi Sakurai, Classification on attacks in wireless ad hoc networks
A game theoretic view, 7th International Conference on Networked Computing and Advanced Information Management, NCM 2011 Proceedings - 7th International Conference on Networked Computing and Advanced Information Management, NCM 2011, 144-149, 2011, Wireless ad hoc network is suitable for a large range of applications but vulnerable to various attacks due to its special characteristics. Despite of the vital importance and ongoing research efforts, the security of wireless ad hoc network remains an open problem. Recently, game theory has been receiving immense concern. It provides rich set of mathematical tools for analyzing attacks and designing corresponding countermeasures. However, game theoretic approaches cannot directly be applicable to all kinds of attacks. In this paper, we present a classification which associates the characteristics of attacks with the applicability of game theory. By illustrating the different players in a variety of game models, we provide a comprehensive view on game based solutions to attacks in wireless ad hoc networks..
224. Liang Zhao, Avishek Adhikari, Di Xiao, Kouichi Sakurai, Cryptanalysis on an image scrambling encryption scheme based on pixel bit, 9th International Workshop on Digital Watermarking, IWDW 2010 Digital Watermarking - 9th International Workshop, IWDW 2010, Revised Selected Papers, 10.1007/978-3-642-18405-5-5, 6526 LNCS, 45-59, 2011, Recently, an image scrambling encryption algorithm which makes use of one-dimensional chaos system for shuffling the pixel bits was proposed in [G.-D. Ye, Pattern Recognition Lett. 31(2010) 347-354]. Through the scrambling algorithm, the pixel locations and values can be encrypted at the same time. This scheme can be thought of as a typical binary image scrambling encryption considering the bit-plain of size Mx8. In [Li C.Q., Lo K. T., http://arxiv.org/PS-cache/arxiv/pdf/0912/0912.1918v2.pdf], Li et al. proposed an attack using more than [log2(8MN-1)] many known-plaintext images to recover the original plain image with the noise of size M x N. The same principle is also suitable for the chosen-plaintext attack which can obtain the exact plain image. In the current paper, a simple attack on the original scheme is presented by applying chosen-plaintext images. Using our attack, the encryption vectors TM and TN and the decryption vectors TM′ and TN′ can be recovered completely. The experimental simulations on two standard images of size 128 x 128 and 256 x 256 justify our analysis. It is shown that the recovered images are identical with the corresponding original images. For both the original images, the number of chosen-plaintext images required in our scheme is 9, where as to do the same using the scheme proposed in Li et al.' attack, at least 17 and 19 chosen-plaintext images there will be required respectively. Moreover, the some method can be also used for chosen-ciphertext attack which reveals the decryption vectors TM′ and TN′ directly. Note that our attacks are also successful under iteration system which is remarked in the conclusions..
225. Kenichi Takahashi, Takanori Matsuzaki, Tsunenori Mine, Kouichi Sakurai, Customized program protection for a user customized data protection framework, 2011 IEEE International Conference on Computer Science and Automation Engineering, CSAE 2011 Proceedings - 2011 IEEE International Conference on Computer Science and Automation Engineering, CSAE 2011, 10.1109/CSAE.2011.5953301, 1, 643-649, 2011, Some of Internet services require users to provide their sensitive information such as their name, address, credit card number, and an ID-password pair. In these services, the manner in which the provided information is used is solely determined by the service providers. As a result, even when the manner in which information is used by a service provider appears vulnerable, users have no choice but to allow such usage. Therefore, we have proposed a user customized data protection framework that enables users to select the manner in which their sensitive information is protected. In our framework, a user selects a policy that defines the manner in which his/her information is to be protected and its manner defined by the policy is incorporated into a program. By allowing a service provider to the information provided by a user through the program, the user can protect his/her sensitive information in a manner selected by him/her. This framework works well when existing a manner (protection policy) which is tolerant to the alteration of the program, otherwise, a program alteration might be a concern. Therefore, in this paper, we attempts to protect a customized program by using program obfuscation and sanitizable signature techniques..
226. Jun Furukawa, Akihiro Sakai, Takashi Nishide, Yoshiaki Hori, Kouichi Sakurai, Design and implementation of a forced encryption kernel module, 2011 5th International Conference on Innovative Mobile and Internet Services in Ubiquitous Computing, IMIS 2011 Proceedings - 2011 5th International Conference on Innovative Mobile and Internet Services in Ubiquitous Computing, IMIS 2011, 10.1109/IMIS.2011.68, 607-611, 2011, Access control mechanisms such as access control lists (ACLs)are often used against divulging of sensitive information. However, when this is implemented as apart of a kernel, if someone stole the storage media, he can easily avoid the access control mechanisms. To complement the defect of the access control mechanisms, we designed and implemented an LKM that applies forced encryption to the data that is transmitted to an external storage media. Advantages of our LKM-based approach include fast encryption in kernel space, easy activation/deactivation of the functionality and the possibility to easily share encrypted files within an authorized group..
227. Takashi Nishide, Kouichi Sakurai, Distributed Paillier cryptosystem without trusted dealer, 11th International Workshop on Information Security Applications, WISA 2010 Information Security Applications - 11th International Workshop, WISA 2010, Revised Selected Papers, 10.1007/978-3-642-17955-6-4, 6513 LNCS, 44-60, 2011, We propose a distributed key generation protocol for the threshold Paillier cryptosystem. Often in the multiparty computation based on the threshold Paillier cryptosystem, the existence of a trusted dealer is assumed to distribute secret key shares, but it can be a single point of attack, so it is not preferable. Building on the threshold Paillier cryptosystem with a trusted dealer, we show how to eliminate the trusted dealer by robust distributed key generation without using safe primes..
228. Jianer Chen, Kouichi Sakurai, Cho Li Wang, FCST 2011
Welcome message from the program chairs, Quaternary International, 10.1109/TrustCom.2011.268, 2011.
229. Yizhi Ren, Mingchu Li, Kouichi Sakurai, FineTrust
A fine-grained trust model for peer-to-peer networks, Security and Communication Networks, 10.1002/sec.165, 4, 1, 61-69, 2011, Trust research is a key issue in peer-to-peer (P2P) networks. Reputation-based trust models as one of the good solutions to resolve the trust problems in P2P network are received more and more attention in recent years. One of the fundamental challenges is to capture the evolving nature of a trust relationship between peers and reflect the varied bias or preference of peers in a distributed and open environment. In this paper, we present a fine-grained trust computation model for P2P networks. Our model defines the service as a fined-grained quality-of-service (QoS) (N-dimensional vector), and in order to accurate the recommendation trust computing, several concepts are introduced to reflect the recommenders' current status, history behavior, and the gap between these two behaviors. Also, we firstly introduce the Gauss-bar function to measure the preference similarity between peers. All these will result in a flexible model which represents trust in a manner more close to human intuitions and satisfies the diverse QoS requirements of peers in P2P networks. The extensive simulations have confirmed the efficiency of our model..
230. Guojun Wang, Laurence T. Yang, Kouichi Sakurai, Guest editorial
Trusted computing and communications, Security and Communication Networks, 10.1002/sec.195, 4, 1, 1-2, 2011.
231. Ryuzou Nishi, Kirill Morozov, Yoshiaki Hori, Kouichi Sakurai, Improvement on secrecy capacity of wireless LAN using matched filter, 2011 7th International Conference on Mobile Ad-hoc and Sensor Networks, MSN 2011 Proceedings - 2011 7th International Conference on Mobile Ad-hoc and Sensor Networks, MSN 2011, 10.1109/MSN.2011.40, 463-469, 2011, Wire-tap channel coding allows information-theoretically secure communication between legitimate sender and receiver in presence of an eavesdropper Eve, whose channel is subject to noise. A secrecy capacity for their communication is equal to capacity of the channel connecting them, minus capacity of Eve's channel, when the channels are assumed independent and affected by additive white Gaussian noise. In order to increase the secrecy capacity, we propose to employ a coding scheme using matched filter. The legitimate parties are assumed to share a pre-shared key of the matched filter, secretly from Eve. Hereby, the legitimate parties can use it to increase the capacity of their channel, while Eve cannot. We propose to apply this scheme to indoor wireless communication over IEEE 802.11 wireless LAN, analyze advantages of our construction and discuss an appropriate selection of coding scheme fitting the IEEE 802.11 protocol specification..
232. Na Ruan, Yizhi Ren, Yoshiaki Hori, Kouichi Sakurai, Performance analysis of key management schemes in wireless sensor network using analytic hierarchy process, 10th IEEE Int. Conf. on Trust, Security and Privacy in Computing and Communications, TrustCom 2011, 8th IEEE Int. Conf. on Embedded Software and Systems, ICESS 2011, 6th Int. Conf. on Frontier of Computer Science and Technology, FCST 2011 Proc. 10th IEEE Int. Conf. on Trust, Security and Privacy in Computing and Communications, TrustCom 2011, 8th IEEE Int. Conf. on Embedded Software and Systems, ICESS 2011, 6th Int. Conf. FCST 2011, 10.1109/TrustCom.2011.243, 1739-1744, 2011, To achieve security in wireless sensor networks (WSNs), key management is one of the most challenging issues in design of WSN due to resource-constrained sensor nodes. Various key management schemes (KMs) have been proposed to enable encryption and authentication in WSN for different application scenarios. According to different equirements, it is important to select the trustworthy KMs in a WSN for setting up a fully appropriate WSN mechanism. An Analytic Hierarchy Process (AHP)-aided method helping with the complex decision has been presented in our previous work. Our purpose in this paper is to do performance analysis of KMs in WSN using our previous AHP-aided method. We analyze the characters of abundance KMs intuitively. The following five performance criteria are considered: scalability, key connectivity, resilience, storage overhead and communication overhead. As all permutations of five performance criteria include 120 types' situations, experimental analyses on 43 KMs for the optimum selection are presented..
233. Ilsun You, Christian W. Probst, Yoshiaki Hori, Kouichi Sakurai, Welcome message from MIST-2011 international workshop co-chairs, Quaternary International, 10.1109/INCoS.2011.171, 2011.
234. Huafei Zhu, Tadashi Araragi, Takashi Nishide, Kouichi Sakurai, Adaptive and composable non-committing encryptions, 15th Australasian Conference on Information Security and Privacy, ACISP 2010 Information Security and Privacy - 15th Australasian Conference, ACISP 2010, Proceedings, 10.1007/978-3-642-14081-5_9, 6168 LNCS, 135-144, 2010.12, In this paper, a new non-committing encryption protocol without failure during the course of a channel setup procedure is constructed and analyzed in the universally composable (UC) framework. We show that the proposed non-committing scheme realizes the UC-security in the presence of adaptive adversary assuming that the decisional Diffie-Hellman problem is hard..
235. Kazuhide Fukushima, Shinsaku Kiyomoto, Toshiaki Tanaka, Kouichi Sakurai, Improved subset difference method with ternary tree, IEICE Transactions on Fundamentals of Electronics, Communications and Computer Sciences, 10.1587/transfun.E93.A.2034, E93-A, 11, 2034-2044, 2010.11, This paper proposes a ternary subset difference method (SD method) that is resistant to coalition attacks. In order to realize a secure ternary SD method, we design a new cover-finding algorithm, label assignment algorithm and encryption algorithm. These algorithms are required to revoke one or two subtrees simultaneously while maintaining resistance against coalition attacks. We realize this two-way revocation mechanism by creatively using labels and hashed labels. Then, we evaluate the efficiency and security of the ternary SD method. We show that the number of labels on each client device can be reduced by about 20.4 percent. The simulation results show that the proposed scheme reduces the average header length by up to 15.0 percent in case where the total number of devices is 65,536. On the other hand, the computational cost imposed on a client device stays within O(log n). Finally, we prove that the ternary SD method is secure against coalition attacks..
236. Jingyu Hua, Takashi Nishide, Kouichi Sakurai, Model-based intrusion detection by abstract interpretation, 2010 10th Annual International Symposium on Applications and the Internet, SAINT 2010 Proceedings - 2010 10th Annual International Symposium on Applications and the Internet, SAINT 2010, 10.1109/SAINT.2010.107, 359-362, 2010.11, Model-based intrusion detection works by comparing a process's runtime behavior with a pre-computed normal program model. This paper studies this technology from the viewpoint of abstract interpretation theory. We regard different program behavior models used to perform intrusion detection as different abstractions of the concrete trace semantics of programs. Based on this point, we formally define model-based intrusion detection and present a generic generation algorithm for program models on a provided abstraction domain. Eventually, we discuss how to use this mechanism to implement a real intrusion detection model proposed by us before..
237. Heru Sukocof, Yoshiaki Hori, Hendrawan, Kouichi Sakurai, Towards a fairness multimedia transmission using layered-based multicast protocol, IEICE Transactions on Information and Systems, 10.1587/transinf.E93.D.2953, E93-D, 11, 2953-2961, 2010.11, The distribution of streaming multicast and real time audio/video applications in the Internet has been quickly increased in the Internet. Commonly, these applications rarely use congestion control and do not fairly share provided network capacity with TCP-based applications such as HTTP, FTP and emails. Therefore, Internet communities will be threatened by the increase of non-TCP-based applications that likely cause a significant increase of traffics congestion and starvation. This paper proposes a set of mechanisms, such as providing various data rates, background traffics, and various scenarios, to act friendly with TCP when sending multicast traffics. By using 8 scenarios of simulations, we use 6 layered multicast transmissions with background traffic Pareto with the shape factor 1.5 to evaluate performance metrics such as throughput, delay/latency, jitter, TCP friendliness, packet loss ratio, and convergence time. Our study shows that non TCP traffics behave fairly and respectful of the co-existent TCP-based applications that run on shared link transmissions even with background traffic. Another result shows that the simulation has low values on throughput, vary in jitter (0-10 ms), and packet loss ratio > 3%. It was also difficult to reach convergence time quickly when involving only non TCP traffics..
238. Amril Syalim, Takashi Nishide, Kouichi Sakurai, Preserving integrity and confidentiality of a directed acyclic graph model of provenance, 24th Annual IFIP WG 11.3 Working Conference on Data and Applications Security and Privacy Data and Applications Security and Privacy XXIV - 24th Annual IFIP WG 11.3 Working Conference, Proceedings, 10.1007/978-3-642-13739-6_22, 6166 LNCS, 311-318, 2010.10, This paper describes how to preserve integrity and confidentiality of a directed acyclic graph (DAG) model of provenance database. We show a method to preserve integrity by using digital signature where both of the provenance owner and the process executors (i.e. contributors) sign the nodes and the relationships between nodes in the provenance graph so that attacks to integrity can be detected by checking the signatures. To preserve confidentiality of the nodes and edges in the provenance graph we propose an access control model based on paths on the provenance graph because an auditor who need to audit a result normally need to access all nodes that have causal relationship with the result (i.e. all nodes that have a path to the result). We also complement the path-based access control with a compartment-based access control where each node is classified into compartments and the auditor is not allowed to access the nodes included in a compartment that can not be accessed by him/her (because of the sensitivity of the compartment). We implement the path-based access control by encrypting the nodes and later store encrypted encryption's keys in the children of the nodes. The compartment-based access control is implemented by encrypting the nodes in different compartments with different keys. We developed a prototype of the model and performed experiments to measure the overhead of digital signature and the double encryptions..
239. Jingyu Hua, Kouichi Sakurai, Modeling and containment of search worms targeting web applications, 7th GI International Conference on Detection of Intrusions and Malware and Vulnerability Assessment, DIMVA 2010 Detection of Intrusions and Malware, and Vulnerability Assessment - 7th International Conference, DIMVA 2010, Proceedings, 10.1007/978-3-642-14215-4_11, 6201 LNCS, 183-199, 2010.08, Many web applications leak sensitive pages (we name them eigenpages) that can disclose their vulnerabilities. As a result, some worms like Santy locate their targets by searching specific eigenpages in search engines with well-crafted keywords. Such worms are so called search worms. In this paper, we focus on the modeling and containment of these search worms. We first study the influence of the eigenpage distribution on their spreading by introducing two propagation models: U-Model assuming eigenpages uniformly distributed on servers and PL-Model assuming the distribution follows a power law. We show that the uniform distribution maximizes the spreading speed of the search worm. Then we study the influence of the page ranking and introduce another propagation model: PR-Model. In this model, search results are ranked based on their PageRank values and the relative importance of their resident servers. Finally, we propose a containment system for search worms based on honey-page insertion: a small number of fake pages which will induce visitors to pre-established honeypots are randomly inserted into search results, and then infectious can be detected and reported to search engines when their malicious scans hit honeypots. We study the relationship between the containment effectiveness and the honey-page insert rate with our propagation models and find that the Santy worm can be almost completely stopped at its early age by inserting no more than 2 honey pages in every 100 search results, which is extremely effective..
240. Hui Zhao, Mingchu Li, Kouichi Sakurai, Yizhi Ren, Mechanized analysis of verifiable multi-secret sharing in the appliedPi-calculus, ICIC Express Letters, 4, 3, 1053-1058, 2010.06, In this paper, we give an abstraction of verifiable multi-secret sharingschemes that is accessible to a, fully mechanized analysis. The abstraction isformalized, within the applied, pi-calculus using an equational theory thatabstractly characterizes the cryptographic semantics of secret share. Based onthat, we verify the threshold certificate protocol in a convergent rewritingsystem suitable for the automated protocol verifier Pro Verif. ICIC International.
241. Yoshiro Fukushima, Akihiro Sakai, Yoshiaki Hori, Kouichi Sakurai, A behavior based malware detection scheme for avoiding false positive, 2010 6th IEEE Workshop on Secure Network Protocols, NPSec 2010 2010 6th IEEE Workshop on Secure Network Protocols, NPSec 2010, 10.1109/NPSEC.2010.5634444, 79-84, 2010, The number of malware is increasing rapidly and a lot of malware use stealth techniques such as encryption to evade pattern matching detection by anti-virus software. To resolve the problem, behavior based detection method which focuses on malicious behaviors of malware have been researched. Although they can detect unknown and encrypted malware, they suffer a serious problem of false positives against benign programs. For example, creating files and executing them are common behaviors performed by malware, however, they are also likely performed by benign programs thus it causes false positives. In this paper, we propose a malware detection method based on evaluation of suspicious process behaviors on Windows OS. To avoid false positives, our proposal focuses on not only malware specific behaviors but also normal behavior that malware would usually not do. Moreover, we implement a prototype of our proposal to effectively analyze behaviors of programs. Our evaluation experiments using our malware and benign program datasets show that our malware detection rate is about 60% and it does not cause any false positives. Furthermore, we compare our proposal with completely behavior-based anti-virus software. Our results show that our proposal puts few burdens on users and reduces false positives..
242. Tadashi Kiuchi, Yoshiaki Hori, Kouichi Sakurai, A design of history based traffic filtering with probabilistic packet marking against DoS attacks, 2010 10th Annual International Symposium on Applications and the Internet, SAINT 2010 Proceedings - 2010 10th Annual International Symposium on Applications and the Internet, SAINT 2010, 10.1109/SAINT.2010.44, 261-264, 2010, Recently, one of threats on the increasing network includes DoS(Denial of Service) attacks. A large amount of packets is transmitted to a server that becomes a target of DoS attacks. Therefore, a packet filtering that intercepts the communication of a doubtful packet is researched. We investigate two packet filtering methods. In the history based filtering, it looks for IP addresses that frequently appears at a router. DoS attack traffic is filtered by filtering IP address not observed usually so much. However, the filtering method is weak when the attacker know how to filtering. In the filtering approach that uses the probabilistic packet marking, a communication from an attack path is intercepted and the technique for intercepting the attack is proposed. However, an non-attacker's communication is also intercepted, and there is a problem that the number of packets necessary for the route construction increases according to a superscription of mark information. Then, to solve both problems of the expression, it proposes the probabilistic packet marking with and the filtering approach using the observation of transmission source IP address. The attack path is specified from mark information when an attack starts, and an attack packet is filtered from the record and mark information on an address of the router. It becomes possible to prevent packets being filtered when packets sent by a result and regular those who communicate is marked on the attack path. This technique achieve low false positive of benign traffic..
243. Huafei Zhu, Tadashi Araragi, Takashi Nishide, Kouichi Sakurai, Adaptive and composable non-interactive string-commitment protocols, International Conference on Security and Cryptography, SECRYPT 2010 SECRYPT 2010 - Proceedings of the International Conference on Security and Cryptography, 354-361, 2010, Designing non-committing encryptions tolerating adaptive adversaries is a challenging task. In this paper, a simple implementation of non-committing encryptions is presented and analyzed in the strongest security model. We show that the proposed non-committing encryption scheme is provably secure against adaptive adversaries in the universally composable framework assuming that the decisional Diffie-Hellman problem is hard..
244. Shinichi Matsumoto, Kouichi Sakurai, A proposal for the privacy leakage verification tool for android application developers, 7th International Conference on Ubiquitous Information Management and Communication, ICUIMC 2013 Proceedings of the 7th International Conference on Ubiquitous Information Management and Communication, ICUIMC 2013, 10.1145/2448556.2448610, 2013, Nowadays, smartphone market has been growing rapidly, and smartphone has become essential as a business tool. One of the crucial advantages of a smartphone is an installable third-party application. Number of these has continued to grow explosively. However, vulnerabilities in smartphone applications are seemed as serious problem. This is not only for the smartphone users, also for smartphone application developers and/or vendors. Until now, most vulnerability tests on smartphone applications are targeted that has been packaged as a commercial product and distributed in application marketplaces. These tests are performed on dynamically on application binaries. In this paper, we aim to develop the static vulnerability verification tool that can be utilized for smartphone application developers and/or vendors in the implementation and/or test phase of development process. This tool intakes source codes and determine where to read the privacy information in the source codes, and determine where to write/send the information in there. Then analyze the privacy information transfer and/or transform flow and report the possibilities of privacy information leakage to application developers..
245. Vincenzo Piuri, Jose M.Alcaraz Calero, Kouichi Sakurai, Yiming Pi, DASC 2013
Message from the general chairs, Proceedings - 2013 IEEE 11th International Conference on Dependable, Autonomic and Secure Computing, DASC 2013, 10.1109/DASC.2013.7, 2013.
246. Kazumasa Yamauchi, Yoshiaki Hori, Kouichi Sakurai, Detecting HTTP-based botnet based on characteristic of the C&C session using by SVM, 2013 8th Asia Joint Conference on Information Security, AsiaJCIS 2013 Proceedings - 2013 8th Asia Joint Conference on Information Security, AsiaJCIS 2013, 10.1109/ASIAJCIS.2013.17, 63-68, 2013, With the spread of computer, the increase of malware is a serious problem. In some malware, damage caused by botnet is a serious problem. Botnets perform the attack by remote control. The purpose of the present work is to suppress the botnet activity by detecting the C&C traffic through well-suited observations. There already exists many detection techniques, most of which focus on IRC-based botnet, and very little focus on HTTP-based botnet, even less, which include comparisons between both detection techniques. In this work, we focus on the HTTP-based botnet, and in order to classify normal HTTP session and C&C session, we make use of Support Vector Machine..
247. Yuuki Nishimoto, Naoya Kajiwara, Shinichi Matsumoto, Yoshiaki Hori, Kouichi Sakurai, Detection of android API call using logging mechanism within android framework, 9th International Conference on Security and Privacy in Communication Networks, SecureComm 2013 Security and Privacy in Communication Networks - 9th International ICST Conference, SecureComm 2013, Revised Selected Papers, 127 LNICST, 393-404, 2013, Android based smartphones have become popular. Accordingly, many malwares are developed. The malwares target information leaked from Android. However, it is difficult for users to judge the availability of application by understanding the potential threats in the application. In this paper, we focus on acquisition of information by using a remote procedure call when we invoke the API to acquire phone ID. We design a methodology to record invocation that are concerned the API by inserting Log.v methods. We examined our method, and confirm empirically the record of the call behavior of the API to acquire phone ID..
248. Satoshi Tanaka, Takanori Yasuda, Bo Yin Yang, Chen Mou Cheng, Kouichi Sakurai, Efficient computing over GF(216) using graphics processing unit, 7th International Conference on Innovative Mobile and Internet Services in Ubiquitous Computing, IMIS 2013 Proceedings - 7th International Conference on Innovative Mobile and Internet Services in Ubiquitous Computing, IMIS 2013, 10.1109/IMIS.2013.151, 843-846, 2013, Evaluating non-linear multivariate polynomial systems over finite fields is an important subroutine, e.g., for encryption and signature verification in multivariate cryptography. The security of multivariate cryptography definitely becomes lower if a larger field is used instead of GF(2) given the same number of bits in the key. However, we still would like to use larger fields because multivariate cryptography tends to run faster at the same level of security if a larger field is used. In this paper, we compare the efficiency of several techniques for evaluating multivariate polynomial systems over GF(2 16) vi their implementations on graphics processing units..
249. Yasufumi Hashimoto, Tsuyoshi Takagi, Kouichi Sakurai, General fault attacks on multivariate public key cryptosystems, IEICE Transactions on Fundamentals of Electronics, Communications and Computer Sciences, 10.1587/transfun.E96.A.196, E96-A, 1, 196-205, 2013, The multivariate public key cryptosystem (MPKC), which is based on the problem of solving a set of multivariate systems of quadratic equations over a finite field, is expected to be secure against quantum attacks. Although there are several existing schemes in MPKC that survived known attacks and are much faster than RSA and ECC, there have been few discussions on security against physical attacks, aside from the work of Okeya et al. (2005) on side-channel attacks against Sflash. In this study, we describe general fault attacks on MPKCs including Big Field type (e.g. Matsumoto-Imai, HFE and Sflash) and Stepwise Triangular System (STS) type (e.g. UOV, Rainbow and TTM/TTS). For both types, recovering (parts of) the secret keys S, T with our fault attacks becomes more efficient than doing without them. Especially, on the Big Field type, only single fault is sufficient to recover the secret keys..
250. Rimba Whidiana Ciptasari, Kyung Hyune Rhee, Kouichi Sakurai, Image splicing verification based on pixel-based alignment method, 11th International Workshop on Digital Forensics and Watermaking, IWDW 2012 Digital Forensics and Watermaking - 11th International Workshop, IWDW 2012, Revised Selected Papers, 10.1007/978-3-642-40099-5_17, 7809 LNCS, 198-212, 2013, Due to the easy manipulation and alteration of digital images using widely available software tools, forgery detection is emerged as a primary goal in image forensics. A common form of manipulation is to combine parts of the image fragment into another different image to remove objects from the image. Inspired by the image registration concept, we exploit the correlation-based alignment method to automatically identify the spliced region in any fragment of the reference images. We show the efficacy of the proposed scheme on revealing the source of spliced regions. We anticipate this scheme to be the first concrete technique towards appropriate tools which are necessary for exposing digital forgeries..
251. Laiping Zhao, Kouichi Sakurai, Improving Cost-Efficiency through Failure-Aware Server Management and Scheduling in Cloud, 2nd International Conference on Cloud Computing and Services Science, CLOSER 2012 Cloud Computing and Services Science - 2nd International Conference, CLOSER 2012, Revised Selected Papers, 10.1007/978-3-319-04519-1_2, 367 CCIS, 23-38, 2013, We examine the problem of managing a server farm in a cost-efficient way that reduces the cost caused by server failures, according to an Infrastructure-as-a-Service model in cloud. Specifically, failures in cloud systems are so frequent that severely affect the normal operation of job requests and incurring high penalty cost. It is possible to increase the net revenue through reducing the energy cost and penalty by leveraging failure predictiors. First, we incorporate the malfunction and recovery states into the server management process, and improve the cost-efficiency of each server using failure predictor-based proactive recovery. Second, we present a revenue-driven cloud scheduling algorithm, which further increases net revenue in collaboration with server management algorithm. The formal and experimental analysis manifests our expected net revenue improvement..
252. Sushmita Ruj, Kouichi Sakurai, Secure and privacy preserving hierarchical wireless sensor networks using hybrid key management technique, 2013 IEEE Global Communications Conference, GLOBECOM 2013 2013 IEEE Global Communications Conference, GLOBECOM 2013, 10.1109/GLOCOM.2013.6831104, 402-407, 2013, We propose a key management scheme for two-tire hierarchical mobile network using triple key distribution. Sensor nodes are divided into clusters managed by cluster heads which collect and aggregate data and send to base stations. The use of both symmetric and public key techniques makes the network highly resilient to node compromise. The nodes are resource constrained and thus communicate securely using symmetric triple key distribution technique. The cluster heads are powerful and use asymmetric key distribution techniques. The anonymity of cluster heads while forwarding messages is also preserved in our protocol. To the best of our knowledge, this is the first key management scheme which uses both symmetric and asymmetric triple key distribution mechanism. The analysis shows that our scheme is highly secure, preserves privacy of cluster heads and can support efficient addition and deletion of nodes..
253. Amril Syalim, Takashi Nishide, Kouichi Sakurai, Supporting secure provenance update by keeping "provenance" of the provenance, International Conference on Information and Communication Technology, ICT-EurAsia 2013 Information and Communication Technology - International Conference, ICT-EurAsia 2013, Proceedings, 10.1007/978-3-642-36818-9_40, 7804 LNCS, 363-372, 2013, Provenance of data is a documentation of the origin and processes that produce the data. Many researchers argue that the provenance should be immutable: once a provenance is submitted, it should not be changed or updated. A main reason is that the provenance represents the history of data, and the history should not be altered or changed because it represents the fact in the past. Provenance can be represented by a graph, where each node represents the process executed by a party and an edge represents the relationship between two nodes (i.e. a child node uses the outputs of the parent nodes). A method to ensure that the provenance has not been updated is by using signature chain, where the signatures of the parent nodes are recorded in the children nodes so that any changes to the parent nodes will raise inconsistencies between the parent and the children. However, sticking to the requirement that the provenance should be immutable requires unlimited data storage and also we have problems whenever we need to update the provenance for an accidental error. In this paper, we propose a method that allows updates in the signature chain-based secure provenance, while keeping the signature consistent. The main idea is by keeping the "provenance" of the provenance itself, that is the history of update of the provenance, in the form of the signatures of the previous versions of the nodes. We implement the idea by keeping the signatures of the previous version in a signature tree similar to the Merkle-tree, where the a parent node in tree is the aggregate signature of the children. Using this method, the storage requirement to store signatures is always smaller than the number of updates..
254. Nobuyuki Teraura, Kunio Ito, Naoki Takahashi, Kouichi Sakurai, The development of radiation-resistant rf TAGS for use at nuclear power plants, 2013 21st International Conference on Nuclear Engineering, ICONE 2013 Plant Operations, Maintenance, Engineering, Modifications, Life Cycle and Balance of Plant; Nuclear Fuel and Materials; Radiation Protection and Nuclear Technology Applications, 10.1115/ICONE21-16605, 1, 2013, RF tags based on RFID (Radio-frequency Identification) technology have been widely used in various fields including power plant construction and maintenance for the purpose of improving the identification and traceability of the many components in the facility. To date, various types of tags have been developed, including tags that are resistant to chemicals or high-temperature environments, which are used in specialized fields. When considering widespread use of RF tags in nuclear power plants, there is a concern about the effects of radiation on the RF tags, because the data stored in the tag may receive radiation damage, resulting in corruption of data. Here, we describe a newly designed RF tag that achieves resistance to radiation damage by attaching a radiation shield layer and incorporating automatic data-correction software. This radiation-resistant RF tag has been tested under real radiation exposure fields to verify the intended radiation-resistant functions. It is expected that the use of these radiation-resistant RF tags with a data reader and database system will increase the capabilities of RF tags applied to nuclear power plants and it is also expected to lead to reductions in worker radiation exposure doses..
255. Kouichi Sakurai, Dieter Gollmann, Guest editorial
Managing insider security threats (MIST 2012 Volume 1), Journal of Wireless Mobile Networks, Ubiquitous Computing, and Dependable Applications, 3, 4, 1-3, 2012.12, Insider threats are one of the serious hard problems of organizational security because it is often unclear whether or not an actor is an insider, or what we actually mean by "insider". In addition, it is frequently almost impossible to verify if an authorized insider action (authorized at the level of an operational policy) would constitute an insider attack contravening the organizational security policy of an enterprise. Hence, research on how to fight against insider attacks is one of the recent major topics in information security..
256. Kazuhide Fukushima, Shinsaku Kiyomoto, Yutaka Miyake, Kouichi Sakurai, Revocation and tracing based on ternary tree
Towards optimal broadcast encryption scheme, 8th International Joint Conference on e-Business and Telecommunications, ICETE 2011 E-Business and Telecommunications International Joint Conference, ICETE 2011 Seville, Spain, July 18-21, 2011 Revised Selected Papers, 10.1007/978-3-642-35755-8_17, 233-248, 2012.12, This paper proposes a broadcast encryption scheme with traitor tracing based on the ternary tree structure. The subset difference method with ternary tree reduces the communication cost and tracing cost of the original method with the binary tree. However, straightforward expansion of the method ends in failure due to the vulnerability to coalition attacks. Thus, we design a new cover-finding algorithm and label assignment algorithm in order to achieve a coalition-resistant revocation and tracing schemes. Our analysis on efficiency and security shows that our scheme is an improvement of the existing broadcast encryption schemes: complete subtree and subset difference methods..
257. Laiping Zhao, Kouichi Sakurai, Workflow scheduling with fault tolerance, Network and Traffic Engineering in Emerging Distributed Computing Applications, 10.4018/978-1-4666-1888-6.ch005, 94-123, 2012.12, This chapter describes a study on workflow scheduling with fault tolerance. It starts with an understanding on workflow scheduling and fault tolerance technologies independently. Next, the chapter surveys the related works on the combination field of workflow scheduling and fault tolerance technologies. Generally, these works are classified into six categories corresponding to the six fault tolerance technologies: workflow scheduling with primary/backup, primary/backup with multiple backups, checkpoint, rescheduling, active replication, and active replication with dynamic replicas. An in-depth study on these six topics illustrates the challenge issues explored so far, e.g. overloading conditions, tradeoffs among scheduling criteria, et cetera, and some future research directions are also identified. As applications are increasingly complex, and failures become a severe problem in the large scale systems, the authors expect to provide a comprehensive review on the problem of workflow scheduling with fault tolerance through this work..
258. Liang Zhao, Takashi Nishide, Avishek Adhikari, Kyung Hyune Rhee, Kouichi Sakurai, Cryptanalysis of randomized arithmetic codes based on markov model, 7th China International Conference on Information Security and Cryptography, Inscrypt 2011 Information Security and Cryptology - 7th International Conference, Inscrypt 2011, Revised Selected Papers, 10.1007/978-3-642-34704-7-24, 341-362, 2012.11, An improvement of arithmetic coding based on Markov model () has been proposed in the paper (Duan L.L., Liao X. F., Xiang T., Communications in Nonlinear Science and Numerical Simulation, 2011, 16(6):2554-2562). Though, a methodology to construct the is proposed in the above mentioned paper, it really lacks the formal definition of the. In the current paper, we not only investigate the security analysis of the, but also put forward formal definitions of the as well as its different security notions. Based on those definitions, a chosen-plaintext attack is proposed to reveal the used pseudorandom bit sequence for the encryption under the condition that the same pseudorandom bit sequence is used to encrypt the different messages. We also show that the does not have indistinguishable encryptions under the ciphertext-only attack (i.e., does not have indistinguishable encryptions in the presence of an eavesdropper) even if the different pseudorandom bit sequences are used to encrypt the different messages. Moreover, when the is combined with the randomized arithmetic code () (Grangetto M., Magli E., Olmo G., IEEE Trans. Multimedia, 2006 8(5):905-917), we also explore the insecurity of this combined encryption scheme. The analysis demonstrates that the + is also insecure. Finally, the simulated experimental results show the correctness of all the proposed attacks..
259. Dong Hao, Xiaojuan Liao, Avishek Adhikari, Kouichi Sakurai, Makoto Yokoo, A repeated game approach for analyzing the collusion on selective forwarding in multihop wireless networks, Computer Communications, 10.1016/j.comcom.2012.07.006, 35, 17, 2125-2137, 2012.10, In multihop wireless networks (MWNs), the selective forwarding attack is a special case of denial of service attack. In this attack, the malicious wireless nodes only forward a subset of the received packets, but drop the others. This attack becomes more severe if multiple attackers exist and collude together to disrupt the normal functioning of the secure protocols. By colluding, each attacker can even only drop a little packets, but the overall loss of the path will be high. However, most prior researches on selective forwarding attacks assume the attackers do not collude with each other. Furthermore, the previous works also lack of comprehensive security analysis. In this paper, by utilizing the game theoretic approach, we analyze the collusion in selective forwarding attacks. We first put forward a sub-route oriented punish and reward scheme, and propose an multi-attacker repeated colluding game. Then by static and dynamic analysis of this colluding attack game, we find the sub-game equilibriums which indicate the attackers' optimal attack strategies. Based on the analysis result, we establish a security policies for multihop wireless networks, to threaten and detect the malicious insider nodes which collude with each other to launch the selective forwarding attacks..
260. Chul Sur, Youngho Park, Kouichi Sakurai, Kyung Hyune Rhee, Providing secure location-aware services for cooperative vehicular Ad Hoc networks, Journal of Internet Technology, 13, 4, 631-644, 2012.10, In homeland security, the transportation system built on vehicular ad hoc networks (VANETs) is one sector among key resource sectors for national infrastructure protection plan identified by the department of homeland security (DHS) of the United States. Thus, it is an essential aspect to develop a suit of elaborately designed VANET security mechanisms for a successful homeland security infrastructure. However, all prior privacy-preserving authentication protocols for secure vehicular communications have not satisfied the fulfillment of location assurance to develop secure location-aware service applications in VANETs. In this paper, we make up for the limitations and propose an efficient privacy-preserving authentication protocol with location assurance for secure location-aware services over VANETs. In particular, we introduce the notion of location-aware credential so as to guarantee the trustworthiness of geographic location in location-aware services while providing conditional privacy preservation which is a desirable property for secure vehicular communications. Furthermore, the proposed protocol provides efficient procedures that alleviate a burden of computation for location-aware signature generation and verification on vehicles in VANETs. In order to achieve these goals, we consider online/offline signature scheme based on "hash-sign-switch" paradigm and identity-based aggregate signature scheme as our building blocks. Comprehensive simulations are conducted to confirm the efficiency and effectiveness of the proposed protocol..
261. Dong Hao, Avishek Adhikari, Kouichi Sakurai, Mixed-strategy game based trust management for clustered wireless sensor networks, 3rd International Conference on Trusted Systems, INTRUST 2011 Trusted Systems - Third International Conference, INTRUST 2011, Revised Selected Papers, 10.1007/978-3-642-32298-3_16, 7222 LNCS, 239-257, 2012.09, Wireless sensor networks are vulnerable to a large number of security threats and malicious attacks. The traditional security approaches from encryption and authentication are insufficient to defend the insider attacks which are launched inside of the WSNs and bypass the crypto-based defence. Trust management has been recently suggested as one of the effective security mechanisms for distributed systems, and is a promising new approach to solve the security challenges in wireless sensor networks. However, to the best of our knowledge, it is still a challenge to establish an integrated trust management mechanism with comprehensive security analysis. In this paper, we consider the clustered wireless sensor network in which the cluster head is in charge of the trust management of other sensor nodes. We propose a novel, integrated trust management mechanism for the cluster wireless sensor networks, and analyze the optimal decision making policy by using game theory. First, the upstream/downstream joint monitoring scheme is implemented to securely and efficiently observe the behavior of the insider nodes. Then based on the monitoring results, the local trustworthiness and global trust worthiness are derived based on the trust exchange and the trust computation. Finally, by game theoretic analysis of the security interaction between the attacker and the network, the optimal trust policy can be made based on min-max rule, and the optimal utility of the WSNs can be guaranteed..
262. Laiping Zhao, Kouichi Sakurai, On revenue driven server management incloud, 2nd International Conference on Cloud Computing and Services Science, CLOSER 2012 CLOSER 2012 - Proceedings of the 2nd International Conference on Cloud Computing and Services Science, 295-305, 2012.08, As failures are becoming frequent due to the increasing scale of data centers, Service Level Agreement (SLA) violation often occurs at a cloud provider, thereby affecting the normal operation of job requests and incurring high penalty cost. To this end, we examine the problem of managing a server farm in a way that reduces the penalty caused by server failures according to an Infrastructure-as-a-Service model. We incorporate the malfunction and recovery states into the server management process, and improve the cost efficiency of server management by leveraging the failure predictors. We also design a utility model describing the expected net revenue obtained from providing service. The basic idea is that, a job could be rejected or migrate to another server if a negative utility is anticipated. The formal and experimental analysis manifests our expected net revenue improvement..
263. Liang Zhao, Avishek Adhikari, Di Xiao, Kouichi Sakurai, On the security analysis of an image scrambling encryption of pixel bit and its improved scheme based on self-correlation encryption, Communications in Nonlinear Science and Numerical Simulation, 10.1016/j.cnsns.2011.12.015, 17, 8, 3303-3327, 2012.08, An image scrambling encryption scheme for pixel bits was presented by Ye [Ye GD. Image scrambling encryption algorithm of pixel bit based on chaos map. Pattern Recognit Lett 2010;31:347-54], which can be seen as one kind of typical binary image scrambling encryption considering from the bit-plain of size M×(8N). However, recently, some defects existing in the original image encryption scheme, i.e., Ye's scheme, have been observed by Li and Lo [Li CQ, Lo KT. Optimal quantitative cryptanalysis of permutation-only multimedia ciphers against plaintext attacks. Signal Process 2011;91:949-54]. In the attack proposed by Li and Lo at least 3+⌈log 2(MN)⌉ plain images of size M×N are used to reveal the permutation matrix W=[w(i,k)] (i∈{1, 2,...,M};k∈{1,2,...,8N}) which can be applied to recover the exact plain image. In the current paper, at first, one type of special plain image/cipher image is used to analyze the security weakness of the original image scrambling scheme under study. The final encryption vectors TM and TN or the decryption vectors TM' and TN' are revealed completely according to our attack. To demonstrate the performance of our attack, a quantified comparison is drawn between our attack and the attack proposed by Li and Lo. Compared with Li and Lo's attack, our attack is more efficient in the general conditions. In particular, when the sizes of images satisfy the condition M=N or M≤8N, the number of the used plain images/cipher images is at most 9, which is sharply less than 3+⌈log 2(MN)⌉ when M and N are of large size. To overcome the weaknesses of the original scheme, in this paper, an improved image scrambling encryption scheme is proposed. In the improved scheme, the idea of the "self-correlation" method is used to resist the chosen-plaintext attack/known-plaintext attack. The corresponding simulations and analyses illustrate that the improved encryption method has good cryptographic properties, and can overcome the weakness of the original image encryption scheme. Finally, farther improvement is briefly presented for the future work..
264. Amril Syalim, Takashi Nishide, Kouichi Sakurai, Securing provenance of distributed processes in an untrusted environment, IEICE Transactions on Information and Systems, 10.1587/transinf.E95.D.1894, E95-D, 7, 1894-1907, 2012.07, Recently, there is much concern about the provenance of distributed processes, that is about the documentation of the origin and the processes to produce an object in a distributed system. The provenance has many applications in the forms of medical records, documentation of processes in the computer systems, recording the origin of data in the cloud, and also documentation of human-executed processes. The provenance of distributed processes can be modeled by a directed acyclic graph (DAG) where each node represents an entity, and an edge represents the origin and causal relationship between entities. Without sufficient security mechanisms, the provenance graph suffers from integrity and confidentiality problems, for example changes or deletions of the correct nodes, additions of fake nodes and edges, and unauthorized accesses to the sensitive nodes and edges. In this paper, we propose an integrity mechanism for provenance graph using the digital signature involving three parties: the process executors who are responsible in the nodes' creation, a provenance owner that records the nodes to the provenance store, and a trusted party that we call the Trusted Counter Server (TCS) that records the number of nodes stored by the provenance owner. We show that the mechanism can detect the integrity problem in the provenance graph, namely unauthorized and malicious "authorized" updates even if all the parties, except the TCS, collude to update the provenance. In this scheme, the TCS only needs a very minimal storage (linear with the number of the provenance owners). To protect the confidentiality and for an efficient access control administration, we propose a method to encrypt the provenance graph that allows access by paths and compartments in the provenance graph. We argue that encryption is important as a mechanism to protect the provenance data stored in an untrusted environment. We analyze the security of the integrity mechanism, and perform experiments to measure the performance of both mechanisms..
265. Yichao Xu, Kouichi Sakurai, Cooperatively securing network coding against pollution attacks with incentive mechanism, 6th International Conference on Ubiquitous Information Management and Communication, ICUIMC'12 Proceedings of the 6th International Conference on Ubiquitous Information Management and Communication, ICUIMC'12, 10.1145/2184751.2184815, 2012.05, The availab ility of network system with network coding can suffer from malicious nodes intentionally corrupt the encoded packets. T he sit uat ion will get even worse when t here are self ish nodes that are unwilling to take the measure of securit y mechanism. In such situation, selfish nodes should be motivated to follow the protocol, and malicious nodes need to be detected. We integrate an efficient Homomorphic MAC with a lightweight non-repudiation transmission protocol which can not only detect the corrupted packets but also locate the malicious nodes. In order to deal with the selfish behavior, we propose an incentive scheme which can encourage the nodes to follow the protocol faithfully and detect the pollution attacks. In addition, we analyze the relationship between security and parameters of the protocol, which can help to choose the better parameters the system requires. From the evaluated results, we can see that our design can effectively defense against pollution attacks in the system with network coding with high security and good performance..
266. Laiping Zhao, Yizhi Ren, Mingchu Li, Kouichi Sakurai, Flexible service selection with user-specific QoS support in service-oriented architecture, Journal of Network and Computer Applications, 10.1016/j.jnca.2011.03.013, 35, 3, 962-973, 2012.05, Along with the development of the service-oriented architecture (SOA) and cloud computing, a large number of service providers have created an intense competitive world of business. Consequently, it is becoming increasingly complex to select a service provider for a user as a result of their various economic and social attributes. In this paper, we state the problem of how to find the appropriate services with satisfying the users multiple QoS requirements. We consider the service's response time, trust degree and monetary cost. And inspired from the mode of Web search engine, such as Yahoo, Google, we propose an innovative service selection algorithm for SOA systems. The algorithm can recommend a number of suitable services based on the user's QoS requirements. Compared with the existing scheduling algorithms, our solution is much more flexible in supporting the multiple objectives and user personalization. We study the scalability of the algorithm with different numbers of jobs, service providers and QoS criteria. And we find that it can capture user's preferences value in less than six times of job submissions..
267. Huafei Zhu, Tadashi Araragi, Takashi Nishide, Kouichi Sakurai, Adaptive and composable non-interactive string-commitment protocols, 7th International Joint Conference on e-Business and Telecommunications, ICETE 2010 e-Business and Telecommunications - 7th International Joint Conference, ICETE 2010, Revised Selected Papers, 10.1007/978-3-642-25206-8_15, 222 CCIS, 233-242, 2012.03, In this paper, a non-interactive string-commitment protocol in the common reference string model is presented and analyzed. We show that the proposed (length-flexible) commitment protocol realizes the universally composable security in the presence of adaptive adversaries in the standard computational model assuming that the underlying Paillier's public-key encryption (or Damgård and Jurik's public-key encryption scheme when a lengthflexible property is claimed) is semantically secure and the Damgård-Fazio- Nicolosi's non-interactive protocol is zero-knowledge in the registered public-key model..
268. Takanori Yasuda, Kouichi Sakurai, Tsuyoshi Takagi, Reducing the key size of rainbow using non-commutative rings, 12th Cryptographers' Track at the RSA Conference, CT-RSA 2012 Topics in Cryptology, CT-RSA 2012 - The Cryptographers' Track at the RSA Conference 2012, Proceedings, 10.1007/978-3-642-27954-6_5, 7178 LNCS, 68-83, 2012.03, Multivariate Public Key Cryptosystems (MPKC) are candidates for post-quantum cryptography. Rainbow is a digital signature scheme in MPKC, whose encryption and decryption are relatively efficient. However, the security of MPKC depends on the difficulty in solving a system of multivariate polynomials, and the key length of MPKC becomes substantially large compared with that of RSA cryptosystems for the same level of security. The size of the public key in MPKC has been reduced in previous research, but to the best of our knowledge, there are no algorithms to reduce the size of a private key . In this paper, we propose NC-Rainbow, a variation of Rainbow using non-commutative rings and we describe the ability of the proposed scheme to reduce the size of a private key in comparison with the ordinary Rainbow while maintaining the same level of security. In particular, using the proposed NC-Rainbow, the size of a private key is reduced by about 75% at the 80 bit security level. Moreover, the speed of signature generation is accelerated by about 34% at the 80 bit security level..
269. Takashi Nishide, Shingo Miyazaki, Kouichi Sakurai, Security analysis of offline E-cash systems with malicious insider, Journal of Wireless Mobile Networks, Ubiquitous Computing, and Dependable Applications, 3, 1-2, 55-71, 2012.03, When we build electronic cash systems, the main focus of the design is usually on preventing customers' malicious actions. However, since authorities such as banks and certificate authorities may have important secret data of customers, the insiders in the potentially untrusted authorities can become threats to electronic cash systems. Miyazaki and Sakurai [2] first systematically analyzed security of offline anonymous electronic cash systems by considering the insider threats from untrusted authorities. They investigated the security of the existing electronic cash systems and categorized the systems into four types. In this paper, we reconsider the security of offline anonymous electronic cash systems including more recent systems based on the classification of Miyazaki and Sakurai and investigate the possible effective countermeasures against malicious insiders..
270. Huafei Zhu, Tadashi Araragi, Takashi Nishide, Kouichi Sakurai, Universally composable non-committing encryptions in the presence of adaptive adversaries, 7th International Joint Conference on e-Business and Telecommunications, ICETE 2010 e-Business and Telecommunications - 7th International Joint Conference, ICETE 2010, Revised Selected Papers, 10.1007/978-3-642-25206-8_18, 222 CCIS, 274-288, 2012.03, Designing non-committing encryptions tolerating adaptive adversaries is a challenging task. In this paper, a simple implementation of non-committing encryptions is presented and analyzed in the strongest security model. We show that the proposed non-committing encryption scheme is provably secure against adaptive adversaries in the universally composable framework assuming that the decisional Diffie-Hellman problem is hard..
271. Hui Zhao, Mingchu Li, Kouichi Sakurai, Yizhi Ren, Jonathan Z. Sun, Fengying Wang, A finite equivalence of verifiable multi-secret sharing, International Journal of Computational Intelligence Systems, 10.1080/18756891.2012.670517, 5, 1, 1-12, 2012.01, We give an abstraction of verifiable multi-secret sharing schemes that is accessible to a fully mechanized analysis. This abstraction is formalized within the applied pi-calculus by using an equational theory which characterizes the cryptographic semantics of secret share. We also present an encoding from the equational theory into a convergent rewriting system, which is suitable for the automated protocol verifier ProVerif. Based on that, we verify the threshold certificate protocol in ProVerif..
272. Yaokai Feng, Yoshiaki Hori, Kouichi Sakurai, Junnichi Takeuchi, A behavior-based detection method for outbreaks of low-rate attacks, 2012 IEEE/IPSJ 12th International Symposium on Applications and the Internet, SAINT 2012 Proceedings - 2012 IEEE/IPSJ 12th International Symposium on Applications and the Internet, SAINT 2012, 10.1109/SAINT.2012.50, 267-272, 2012, Low-rate attacks can conceal their traffic because their packets are at very low rates, which make it easy to bury themselves into the normal traffic. Thus, although a number of volume-based detection techniques are able to identify anomalies that trigger significant changes in traffic volume, they are not applicable to detecting low-rate attacks. Because of this, the problem of low-rate attacks has been attracting many researchers in the community of network security. In this study, for the first time we propose a method based on the normal behavior mode of traffic to detect outbreaks of low-rate attacks. The experimental result indicates that our proposal is efficient..
273. Dong Hao, Kouichi Sakurai, A differential game approach to mitigating primary user emulation attacks in cognitive radio networks, 26th IEEE International Conference on Advanced Information Networking and Applications, AINA 2012 Proceedings - 26th IEEE International Conference on Advanced Information Networking and Applications, AINA 2012, 10.1109/AINA.2012.84, 495-502, 2012, In cognitive radio networks, primary user emulation (PUE) attack is a denial-of-service (DoS) attack on secondary users. It means that a malicious attacker sends primary-user-like signals to jam certain spectrum channels during the spectrum sensing period. Sensing the attacker's signal, the legitimate secondary user will regard these channels are used by the primary users, and give up using these attacked channels. In this paper, the interaction between the PUE attacker and the secondary user is modeled as a constant sum differential game which is called PUE attak game. The secondary user's objective is to find the optimal sensing strategy so as to maximize its overall channel usability, while the attacker's objective is to minimize the secondary user's overall channel usability. The Nash equilibrium solution of this PUE attack game is deprived, and the optimal anti-PUE attack strategy is obtained. Numerical results demonstrate the trajectories of the secondary user's optimal channel sensing strategies over time, and also shows that: by following the differential game solution, the secondary user can always optimize its channel usability when confronting PUE attacks..
274. Motoki Kitahara, Takashi Nishide, Kouichi Sakurai, A method for embedding secret key information in RSA public key and its application, 6th International Conference on Innovative Mobile and Internet Services in Ubiquitous Computing, IMIS 2012 Proceedings - 6th International Conference on Innovative Mobile and Internet Services in Ubiquitous Computing, IMIS 2012, 10.1109/IMIS.2012.123, 665-670, 2012, In public key encryption, we need to be able to verify the certificate from a certificate authority to prevent impersonation. In this paper, we propose an encryption system in which we can verify a public key without the certificate. We can realize our encryption system without a impersonation nor a key escrow problem..
275. Rimba W. Ciptasari, Kyung Hyune Rhee, Kouichi Sakurai, An image splicing detection based on interpolation analysis, 13th Pacific-Rim Conference on Multimedia, PCM 2012 Advances in Multimedia Information Processing, PCM 2012 - 13th Pacific-Rim Conference on Multimedia, Proceedings, 10.1007/978-3-642-34778-8_36, 7674 LNCS, 390-401, 2012, With the advent of low-cost and high-resolution digital cameras and sophisticated editing software, it is becoming increasingly easier to tamper with the digital image. A common form of manipulation is to combine parts of the image fragment into another different image to remove objects from the image. Inspired by the digital image correlation concept, we exploit the peak of cross-correlation function to automatically detect the splicing artifacts in any fragment of an image. We show the efficacy of the proposed scheme on revealing the source of spliced regions. We make the first concrete technique towards appropriate tools which are necessary for rendering digital forgeries..
276. Chunhua Su, Guilin Wang, Kouichi Sakurai, Analysis and improvement of privacy-preserving frequent item protocol for accountable computation framework, 11th IEEE International Conference on Trust, Security and Privacy in Computing and Communications, TrustCom-2012 Proc. of the 11th IEEE Int. Conference on Trust, Security and Privacy in Computing and Communications, TrustCom-2012 - 11th IEEE Int. Conference on Ubiquitous Computing and Communications, IUCC-2012, 10.1109/TrustCom.2012.87, 1012-1017, 2012, Nowadays, data collection and processing becomes ubiquitous in social and business areas, especially in Internet of Things. However, sensitive information leakage is a critical issue. To solve problem, privacy-preserving techniques are strongly needed. Jiang {\em et al.} proposed a protocol of finding frequent item in accountable computing (AC) framework which enables two parties to conduct collaborative computation on their transactional databases to find out the common frequent items without disclosing their private data to the other party. Their scheme was proposed in a secure two-party computation model against malicious adversaries. In this paper, we analyze the implementation details of AC-framework and identify some security weaknesses in their scheme. Furthermore, we clarify the security requirements for the AC-framework and present an augmented solution to enhance security..
277. Ruan Na, Yizhi Ren, Yoshiaki Hori, Kouichi Sakurai, Analytic hierarchy process aided key management schemes evaluation in wireless sensor network, Journal of Networks, 10.4304/jnw.7.1.88-100, 7, 1, 88-100, 2012, Wireless sensor networks (WSNs) have been widely used in various applications. Since their sensor nodes are resource-constrained and their security primitives need to store a set of security credentials to share a secure channel, key management is one of the most challenging issues in the design of WSN. Currently, various efficient lightweight key management schemes (KMs) have been proposed to enable encryption and authentication in WSN for different application scenarios. According to different requirements, it is important to select the trustworthy key management schemes in a WSN for setting up a fully trusted WSN mechanism. In this context, adaptive methods are required to evaluate those schemes. In this paper, we exploit Analytic Hierarchy Process (AHP) to help with the complex decision. Specifically, we consider the following performance criteria: scalability, key connectivity, resilience, storage overhead, processing overhead and communication overhead. Two case studies are added for verifying our proposal. Via the two case studies, it is verified that our method is able to help selecting a suitable scheme for given requirements..
278. Takanori Yasuda, Tsuyoshi Takagi, Kouichi Sakurai, Application of scalar multiplication of edwards curves to pairing-based cryptography, 7th International Workshop on Security, IWSEC 2012 Advances in Information and Computer Security - 7th International Workshop on Security, IWSEC 2012, Proceedings, 10.1007/978-3-642-34117-5-2, 7631 LNCS, 19-36, 2012, Edwards curves have efficient scalar multiplication algorithms, and their application to pairing-based cryptography has been studied. In particular, if a pairing-friendly curve used in a pairing-based protocol is isomorphic to an Edwards curve, all the scalar multiplication appearing in the protocol can be computed efficiently. In this paper, we extend this idea to pairing-friendly curves not isomorphic but isogenous to Edwards curves, and add to pairing-friendly curves to which Edwards curves can be applied. Above all, pairing-friendly curves with smaller ρ-values provide more efficient pairing computation. Therefore, we investigate whether pairing-friendly curves with the minimal ρ-values are isogenous to Edwards curves for embedding degree up to 50. Based on the investigation, we present parameters of pairing-friendly curves with 160-bit and 256-bit security level at embedding degree 16 and 24, respectively. These curves have the minimal ρ-values and are not isomorphic but isogenous to Edwards curves, and thus our proposed method is effective for these curves..
279. Jingyu Hua, Kouichi Sakurai, Barrier
A lightweight hypervisor for protecting kernel integrity via memory isolation, 27th Annual ACM Symposium on Applied Computing, SAC 2012 27th Annual ACM Symposium on Applied Computing, SAC 2012, 10.1145/2245276.2232011, 1470-1477, 2012, In the present operating systems such as Linux, all the kernel modules, including unknown extensions, run in the same address space. They are granted the highest privilege and can access arbitrary memory without any limitation. This is at the root of kernel rootkits, which are malware seriously threatening the kernel integrity. In this paper, we present Barrier, a lightweight hypervisor designed for enhancing the kernel integrity of personal computers by isolating the kernel modules. Since this hypervisor is designed for the OS protection on PCs, it does not implement unnecessary virtualization features that are commonly found on the general-purpose hypervisors to support running multiple OS instances concurrently on the same server. As a result, it is much smaller and also much easier to use, especially for unprofessional users. Barrier leverages the hardware-supported memory virtualization to isolate the kernel modules into different address spaces. All the interactions across address spaces have to go through a strict mediation based on some predefined MAC rules. This greatly increases the attacker's hardness to compromise the kernel integrity. We have implemented a prototype of Barrier. The evaluation results show that Barrier can well protect the kernel integrity without bringing unaffordable performance overheads..
280. Satoru Akimoto, Yoshiaki Hori, Kouichi Sakurai, Collaborative behavior visualization and its detection by observing darknet traffic, 4th International Symposium on Cyberspace Safety and Security, CSS 2012 Cyberspace Safety and Security - 4th International Symposium, CSS 2012, Proceedings, 10.1007/978-3-642-35362-8_17, 7672 LNCS, 212-226, 2012, Recently, we have a problem about an attack generated by a botnet which consists of a group of compromised computers called bots. An attacker called botmaster controls it and a botnet invokes an attack such as scanning and DDoS attack. In this paper, we use the 3D-visualization to investigate the change of attack according to the darknet traffic. As a result, we discover the attack in which several source IP addresses transmit packets to a single destination within a short period of time. In addition, we find that the packet size and the destination port number are identical on its attack. Furthermore, we propose the method to detect this attack called behavior of collaborative attack. In our proposal, we focus on the number of source IP addresses which transmit packets to the single destination. We detected this packet and the rate of packet with the same packet size and destination port number occupied about 90% of the set unit of extracted packet..
281. Shogo Nakamura, Yoshiaki Hori, Kouichi Sakurai, Communication-efficient anonymous routing protocol for wireless sensor networks using single path tree topology, 26th IEEE International Conference on Advanced Information Networking and Applications Workshops, WAINA 2012 Proceedings - 26th IEEE International Conference on Advanced Information Networking and Applications Workshops, WAINA 2012, 10.1109/WAINA.2012.175, 766-771, 2012, In recent years, there are anonymous routing protocols for mobile ad-hoc networks. These protocols provide anonymous communication between an arbitrary pair of nodes. However, there are also some multipoint-to-point sensor networks. In those environments, we have to consider all routes not between an arbitrary pair of sensor nodes but between an arbitrary one sender node and a specific destination node. These existing protocols consider to only security, so nodes may not be able to work efficiency in those environments. In this paper, we propose a new anonymous routing protocol for such multipoint-to-point sensor networks based on efficient routing protocols and existing anonymous routing mechanisms. Moreover, we evidence superiority of our proposal by comparing the amount of information for anonymous routing and a time for route establishment with that of existing protocols. We show that our protocol can establish the anonymous route faster than existing ones and reduce the information for routing from existing ones..
282. Liang Zhao, Takashi Nishide, Kouichi Sakurai, Differential fault analysis of full lblock, 3rd International Workshop, Constructive Side-Channel Analysis and Secure Design, COSADE 2012 Constructive Side-Channel Analysis and Secure Design - Third International Workshop, COSADE 2012, Proceedings, 10.1007/978-3-642-29912-4_11, 7275 LNCS, 135-150, 2012, LBlock is a 64-bit lightweight block cipher which can be implemented in both hardware environments and software platforms. It was designed by Wu and Zhang, and published at ACNS2011. In this paper, we explore the strength of LBlock against the differential fault analysis (DFA). As far as we know, this is the first time the DFA attack is used to analyze LBlock. Our DFA attack adopts the random bit fault model. When the fault is injected at the end of the round from the 25 th round to the 31 st round, the DFA attack is used to reveal the last three round subkeys (i.e., K 32, K 31 and K 30) by analyzing the active S-box of which the input and output differences can be obtained from the right and faulty ciphertexts (C, C̃). Then, the master key can be recovered based on the analysis of the key scheduling. Specially, for the condition that the fault is injected at the end of the 25 th and 26 th round, we show that the active S-box can be distinguished from the false active S-box by analyzing the nonzero differences from the pair of ciphertexts (C, C̃). The false active S-box which we define implies that the nonzero input difference does not correspond to the right output difference. Moreover, as the LBlock can achieve the best diffusion in eight rounds, there can exist the countermeasures that protect the first and last eight rounds. This countermeasure raises a question whether provoking a fault at the former round of LBlock can reveal the round subkey. Our current work also gives an answer to the question that the DFA attack can be used to reveal the round subkey when the fault is injected into the 24 th round. If the fault model used in this analysis is a semi-random bit model, the round subkey can be revealed directly. Specially, the semi-random bit model corresponds to an adversary who could know the corrupted 4 bits at the chosen round but not know the exact bit in these 4 bits. Finally, the data complexity analysis and simulations show the number of necessary faults for revealing the master key..
283. Satoshi Tanaka, Takashi Nishide, Kouichi Sakurai, Efficient implementation of evaluating multivariate quadratic system with GPUs, 6th International Conference on Innovative Mobile and Internet Services in Ubiquitous Computing, IMIS 2012 Proceedings - 6th International Conference on Innovative Mobile and Internet Services in Ubiquitous Computing, IMIS 2012, 10.1109/IMIS.2012.139, 660-664, 2012, QUAD stream cipher uses multivariate polynomial systems. It has provable security based on the computational hardness assumption. More specifically, the security of QUAD depends on hardness of solving non-linear multivariate system us over a finite field, and it is known as an NP-Hard problem. However, QUAD is slower than other stream ciphers, and an efficient implementation, which has a reduced computational cost is required. In this paper, we propose an efficient implementation of computing multivariate polynomial systems for multivariate cryptography on GPU and evaluate efficiency of the proposal. GPU is considered to be a commodity parallel arithmetic unit. Moreover, we give an evaluation of our proposal. Our proposal parallelizes an algorithm of multivariate cryptography, and makes it efficient by optimizing the algorithm with GPU..
284. Satoshi Tanaka, Tung Chou, Bo Yin Yang, Chen Mou Cheng, Kouichi Sakurai, Efficient parallel evaluation of multivariate quadratic polynomials on GPUs, 13th International Workshop on Information Security Applications, WISA 2012 Information Security Applications - 13th International Workshop, WISA 2012, Revised Selected Papers, 7690 LNCS, 28-42, 2012, QUAD is a provably secure stream cipher, whose security is based on the hardness assumption of solving multivariate quadratic polynomial systems over a finite field, which is known to be NP-complete. However, such provable security comes at a price, and QUAD is slower than most other stream ciphers that do not have security proofs. In this paper, we discuss two efficient parallelization techniques for evaluating multivariate quadratic polynomial systems on GPU, which can effectively accelerate the QUAD stream cipher. The first approach focuses on formula of summations in quadratics, while the second approach uses parallel reduction to summations. Our approaches can be easily generalized and applied to other multivariate cryptosystems..
285. Nobuyuki Teraura, Kouichi Sakurai, Information hiding in subcells of a two-dimensional code, 1st IEEE Global Conference on Consumer Electronics, GCCE 2012 1st IEEE Global Conference on Consumer Electronics 2012, GCCE 2012, 10.1109/GCCE.2012.6379943, 652-656, 2012, In this paper, we present a method for hiding information in a conventional two-dimensional (2D) code that maintains backward compatibility with conventional 2D code readers. This is achieved by segmenting each cell into subcells that store confidential information..
286. Nobuyuki Teraura, Kouichi Sakurai, Information hiding of two-dimensional code by multi-layer optical, 2012 10th IEEE International Symposium on Parallel and Distributed Processing with Applications, ISPA 2012 Proceedings of the 2012 10th IEEE International Symposium on Parallel and Distributed Processing with Applications, ISPA 2012, 10.1109/ISPA.2012.113, 770-777, 2012, Optical information media printed on paper use printing materials to absorb visible light. There is a two-dimensional code, which may be encrypted but also can possibly be copied. Hence, we envisage an information medium that cannot possibly be copied and thereby offers high security. At the surface, the normal two-dimensional code is printed. The inner layers consist of two-dimensional codes printed using a variety of materials, which absorb certain distinct wavelengths, to form a multilayered two-dimensional code. Information can be distributed among the two-dimensional codes forming the inner layers of the multiplex..
287. Kouichi Sakurai, Lizhe Wang, Ei Sayed M Ei-Alfy, Message from ISSR-2012 workshop chairs, Quaternary International, 10.1109/TrustCom.2012.311, 2012.
288. Fangming Zhao, Takashi Nishide, Kouichi Sakurai, Multi-user keyword search scheme for secure data sharing with fine-grained access control, 14th International Conference on Information Security and Cryptology, ICISC 2011 Information Security and Cryptology, ICISC 2011 - 14th International Conference, Revised Selected Papers, 10.1007/978-3-642-31912-9_27, 7259 LNCS, 406-418, 2012, We consider the problem of searchable encryption scheme for the cryptographic cloud storage in such a way that it can be efficiently and privately executed under the multi-user setting. Searchable encryption schemes allow users to perform keyword searches on encrypted files to retrieve their interested data without decryption. All existing such schemes only consider the straightforward search approach where for searching one encrypted keyword, the cloud server must look round all encrypted files on the storage to compare that encrypted keyword to each keyword index. Since the file number can be very huge and the user may be unable to decrypt all files, that approach is not efficient and secure enough. In this paper, we first propose a keyword search scheme for the cryptographic cloud storage based on attribute-based cryptosystems. Our scheme presents a new keyword search notion: fine-grained access control aware keyword search. By narrowing the search scope to the user's decryptable files' group before executing the keyword search, our approach can both decrease information leakage from the query process and be more efficient than other existing schemes..
289. Nobuyuki Teraura, Kouichi Sakurai, Preventing the access of fraudulent WEB sites by using a special two-dimensional code, 6th International Conference on Innovative Mobile and Internet Services in Ubiquitous Computing, IMIS 2012 Proceedings - 6th International Conference on Innovative Mobile and Internet Services in Ubiquitous Computing, IMIS 2012, 10.1109/IMIS.2012.57, 645-650, 2012, Mobile phone users are being increasingly directed to WEB sites through the identification of the WEB address from a two-dimensional code on the phone. However, incidents where mobile phones direct users to malicious WEB sites are also increasing. The direct lead mechanism, in which mobile phones directly send users to an uninspected WEB address, is the most common mechanism by which users are misdirected to fraudulent WEB sites. To address this issue, a registration server for inspecting WEB addresses and storing the corresponding registration IDs in the two-dimensional code format was established. Subsequently, the reliability of directing users to WEB sites only after verifying the registration ID of the target WEB address was examined. However, this approach was susceptible to phishing and camouflage when malicious software was used to rewrite the registration ID and the relationship of the WEB address on the registration server. Therefore, an approach that uses two-dimensional codes with a secret encrypted component was proposed..
290. Taketoshi Sakuraba, Kouichi Sakurai, Proposal of the hierarchical file server groups for implementing mandatory access control, 6th International Conference on Innovative Mobile and Internet Services in Ubiquitous Computing, IMIS 2012 Proceedings - 6th International Conference on Innovative Mobile and Internet Services in Ubiquitous Computing, IMIS 2012, 10.1109/IMIS.2012.129, 639-644, 2012, An accessible implementation of MAC for file access is proposed. Instead of traditional but unfamiliar MAC aware tools such as secure-OSs, the security enforcement mechanism of our proposal is FSG (file server group) which is structured so that they reflect a security policy of the organization. Using ordinal file servers, it is accessible to the most of commercial office environment. We also propose the use of FCA (formal concept analysis), a technology for knowledge extraction, to derive the structure of FSG for information flow enforcement. An advantage of use of FCA is that it directly produces configuration parameters such as access points of users as the knowledge extracted from organizational security policy. The configuration of the file server group is easy to understand, and the management cost of FSG is lower than that of the ordinary flat structured file servers..
291. Takanori Suga, Takashi Nishide, Kouichi Sakurai, Secure keyword search using bloom filter with specified character positions, 6th International Conference on Provable Security, ProvSec 2012 Provable Security - 6th International Conference, ProvSec 2012, Proceedings, 10.1007/978-3-642-33272-2_15, 7496 LNCS, 235-252, 2012, There are encryption schemes called searchable encryption which enable keyword searches. Traditional symmetric ones support only full keyword matches. Therefore, both a data owner and data searcher have to enumerate all possible keywords to realize a variety of searches. It causes increases of data size and run time.We propose searchable symmetric encryption which can check characters in the specified position as we perform search on plaintexts. Our scheme realizes a variety of searches such as fuzzy keyword search, wildcard search, and so on..
292. Takanori Suga, Takashi Nishide, Kouichi Sakurai, Weakness of provably secure searchable encryption against frequency analysis, 5th Mosharaka International Conference on Communications, Computers and Applications, MIC-CCA 2012 Proceedings of the 5th International Conference on Communications, Computers and Applications, MIC-CCA 2012, 142-147, 2012, There are encryption schemes called searchable encryption schemes. We can prove the security of these schemes based on a security model. However, we face the risk of the frequency analysis in some constructions because these schemes encrypt the keywords per word in the file as well as itself. In this attack, we assume an adversary knows the frequency distribution of plaintexts (i.e., keywords), and an adversary measures the frequency of the ciphertext and guesses the plaintext by comparing the frequency of the plaintext with it. In this work, we apply this attack to the existing works and evaluate the resistance of the searchable encryption to this attack by considering the difference between the deterministic encryption and the probabilistic encryption, and the supported types of searches..
293. Takanori Yasuda, Kouichi Sakurai, A security analysis of uniformly-layered rainbow
Revisiting Sato-Araki's non-commutative approach to Ong-Schnorr-Shamir signature towards postquantum paradigm, 4th International Workshop on Post-Quantum Cryptography, PQCrypto 2011 Post-Quantum Cryptography - 4th International Workshop, PQCrypto 2011, Proceedings, 10.1007/978-3-642-25405-5_18, 7071 LNCS, 275-294, 2011.12, In 1984, Ong, Schnorr and Shamir proposed an efficient signature scheme (OSS signature scheme) using a bivariate quadratic equation. Its security was believed to be based on the difficulty of integer factorization. However, an efficient attack without integer factorization was subsequently found. In 2008, Hashimoto and Sakurai proposed an extended scheme (HS scheme), based on OSS signature scheme that used multivariate and non-commutative ring. HS scheme uses a composite number as a modulus in the same manner as OSS signature scheme. In this paper, we redefine HS scheme in such a way that it deals with not only integers modulo a composite number, but also elements of a finite field. In the case of a finite field, it becomes a scheme in the multivariate public key cryptosystem. In fact, its public key is constructed by a version of Rainbow in which all the components in the parameter are equal. (We call such a Rainbow a uniformly-layered Rainbow.) In particular, our scheme is a candidate for post-quantum cryptography. If a non-commutative ring used in the proposed scheme is chosen by the group ring associated to dihedral group, the speed of the signature generation can be accelerated by about 50% in comparison with the corresponding Rainbow. We analyze the security of the extended HS scheme against some attacks and conclude that if its base field is GF(256), then the dimension of a non-commutative ring must be more than 10 in order to be secure..
294. Zhongqqiang Zhang, Hiroaki Anada, Junpei Kawamoto, Kouichi Sakurai, Detection of illegal players in massively multiplayer online role playing game by classification algorithms, 29th IEEE International Conference on Advanced Information Networking and Applications, AINA 2015 Proceedings - IEEE 29th International Conference on Advanced Information Networking and Applications, AINA 2015, 10.1109/AINA.2015.214, 2015-April, 406-413, 2015.04, Online games have become one of the most popular games in recent years. However, fraud such as real money trading and the use of game bot, has also increased accordingly. In order to maintain a balance in the virtual world, the operators of online games have taken a stern response to the players who conduct fraud. In this study, we have sorted out players' behaviors based on players' game playing time in order to support and find potentially illegal players in the MMORPG. In this paper, we added a topic model to the experiment and used k-means as a major tool to classify the players in the World of War craft Avatar History Dataset and find potentially illegal players..
295. Naoya Kajiwara, Junpei Kawamoto, Shinichi Matsumoto, Yoshiaki Hori, Kouichi Sakurai, Detection of Android ad library focusing on HTTP connections and view object redraw behaviors, 2015 International Conference on Information Networking, ICOIN 2015 2015 International Conference on Information Networking, ICOIN 2015, 10.1109/ICOIN.2015.7057865, 2015-January, 104-109, 2015.03, In recent years, the smart phone application market has expanded rapidly. One of reasons is the popularity of free applications. A developer acquires his revenues by including advertising libraries in his own application. However, some problems about these advertising libraries become clear from recent researches. Especially in the leakage of privacy information is known as a typical problem which advertising libraries cause. In order to solve this problem, the technology which detects advertisement libraries is important. In this paper, we propose a method for detection of Android ad library. We focus on the acquisition and redraw of advertising image operation which are the basic operations of mobile advertisement. Firstly, we tried running some applications with advertisements. Then, It turned out that mobile advertisements acquire advertising images from server and set that image on the screen at a fixed interval. By modifying AndroidOS, logging HTTP connections and View object redraw behaviors, we confirmed the ad image acquisition behavior. Moreover, to take advantage of the periodicity of this behavior, we carried out Fourier-transform the invocation time data of HTTP connections and redraw of View objects. Then, we extracted the periodicity by calculating correlation coefficient for these two data. From the value of correlation coefficient, it is possible to judge whether advertisement library is incorporated into an application or not. As a result, our proposal method results in a output of about 76 % detection rate..
296. Satoshi Tanaka, Chen Mou Cheng, Takanori Yasuda, Kouichi Sakurai, Parallelization of QUAD stream cipher using linear recurring sequences on graphics processing units, 2nd International Symposium on Computing and Networking, CANDAR 2014 Proceedings - 2014 2nd International Symposium on Computing and Networking, CANDAR 2014, 10.1109/CANDAR.2014.85, 543-548, 2015.02, Proposed by Berbain, Gilbert, and Patarin in Euro crypt 2006, QUAD is a provably secure stream cipher. The speed of QUAD depends on the computational cost of evaluating quadratic polynomials over finite fields. For QUAD with m quadratic polynomials in n unknowns over GF (q), this requires O (mn2) GF (q) additions and multiplications. Petzoldt is able to reduce the evaluation cost to O (mn) GF (q) additions and multiplications by using linear recurring sequences to generate the coefficients. In this work, we parallelize and optimize his algorithm for running on Graphics Processing Unit (GPU). The result shows that our GPU implementation of the parallelized algorithm has achieved the best performance in the literature..
297. Jian Weng, Yunlei Zhao, Robert H. Deng, Shengli Liu, Yanjiang Yang, Kouichi Sakurai, A note on the security of KHL scheme, Theoretical Computer Science, 10.1016/j.tcs.2015.07.051, 602, 1-6, 2015.01, A public key trace and revoke scheme combines the functionality of broadcast encryption with the capability of traitor tracing. In Asiacrypt 2003, Kim, Hwang and Lee proposed a public key trace and revoke scheme (referred to as KHL scheme), and gave the security proof to support that their scheme is z-resilient against adaptive chosen-ciphertext attacks, in which the adversary is allowed to adaptively issue decryption queries as well as adaptively corrupt up to z users. In the passed ten years, KHL scheme has been believed as one of the most efficient public key trace and revoke schemes with z-resilience against adaptive chosen-ciphertext attacks under the well-studied DDH assumption. However, in this paper, by giving a concrete attack, we indicate that KHL scheme is actually not secure against adaptive chosen-ciphertexts, even without corruption of any user. We then identify the flaws in the security proof for KHL-scheme, and discuss the consequences of the attack..
298. Satoshi Tanaka, Chen Mou Cheng, Kouichi Sakurai, Evaluation of solving time for multivariate quadratic equation system using XL algorithm over small finite fields on GPU, 2nd International Conference on Mathematics and Computing, ICMC 2015 Mathematics and Computing - ICMC 2015, 10.1007/978-81-322-2452-5_24, 139, 349-361, 2015.01, The security of multivariate public-key cryptography is largely determined by the complexity of solving multivariate quadratic equations over finite fields, a.k.a. the MQ problem. XL (eXtended Linearization) is an efficient algorithm for solving the MQ problem, so its running time is an important indicator for the complexity of solving the MQ problem. In this work, we implement XL on graphics processing unit (GPU) and evaluate its solving time for theMQ problem over several small finite fields, namely, GF(2), GF(3), GF(5), and GF(7). Our implementations can solve MQ instances of 74 equations in 37 unknowns over GF(2) in 36,972 s, 48 equations in 24 unknowns over GF(3) in 933 s, 42 equations in 21 unknowns over GF(5) in 347 s, as well as 42 equations in 21 unknowns over GF(7) in 387 s. Moreover, we can also solve the MQ instance of 48 equations in 24 unknowns over GF(7) in 34,882 s, whose complexity is about O(267) with exhaustive search..
299. Chunlu Chen, Hiroaki Anada, Junpei Kawamoto, Kouichi Sakurai, Hybrid encryption scheme using terminal fingerprint and its application to attribute-based encryption without key misuse, 3rd IFIP TC 5/8 International Conference on Information and Communication Technology, ICT-EurAsia 2015 and 9th IFIP WG 8.9 Working Conference on Research and Practical Issues of Enterprise Information Systems, CONFENIS 2015 Information and Communication Technology - 3rd IFIP TC 5/8 International Conference, ICT-EurAsia 2015 and 9th IFIP WG 8.9 Working Conference, CONFENIS 2015 Held as Part of WCC 2015, Proceedings, 10.1007/978-3-319-24315-3_26, 9357, 255-264, 2015.01, Internet services make sharing digital contents faster and easier but raise an issue of illegal copying and distribution of those digital contents at the same time. A lot of public key encryption schemes solve this issue. However, the secret key is not completely protected i.e. these kinds of encryption methods do not prevent illegal copying and distribution of secret keys. In this paper, we propose a hybrid encryption scheme that employ terminal fingerprints. This scheme is a template to avoid such misuse of secret keys, and can be applied to, for example, attribute-based encryption schemes. There terminal fingerprint information is used to create a second encryption key and secret key. Since the terminal fingerprint is assumed to be unchangeable and unknowable, we ensure that our secret keys are valid in the terminal where such secret keys were created..
300. Hiroaki Anada, Junpei Kawamoto, Jian Weng, Kouichi Sakurai, Identity-embedding method for decentralized public-key infrastructure, 6th International Conference on Trusted Systems, INTRUST 2014 Trusted Systems - 6th International Conference, INTRUST 2014, Revised Selected Papers, 10.1007/978-3-319-27998-5_1, 9473, 1-14, 2015.01, A public key infrastructure (PKI) is for facilitating the authentication and distribution of public keys. Currently, the most commonly employed approach to PKI is to rely on certificate authorities (CAs), but recently there has been arising more need for decentralized peer-to-peer certification like Webs of Trust. In this paper, we propose an identity-embedding method suitable for decentralized PKI. By embed- ding not only ID of the candidate public-key owner itself but also IDs of his guarantors into PK, we can construct Web of guarantors on public keys. Here guarantors can be chosen arbitrarily by the candidate public- key owner. Our embedding method uses a combination of two public-key cryptosystems; the first cryptosystem is for PKI directly. Here we employ a technique to embed a string into a public key of the first cryptosystem. As such a string, we choose a concatenation of ID of a candidate public-key owner, IDs of his guarantors, and a public key of the second cryptosystem. This embedded public key of the second cryptosystem is used by the candidate public-key owner that he certainly knows the secret key that corresponds to the public key of the first cryptosystem. Then, with an aid of a broadcast mechanism of an updated public-key list on a peer-to-peer network, we can attain the decentralized PKI. Such an embedding method is concretely realized by the RSA encryption with the Lenstra’s algorithm, which can be used as the first cryptosystem. As the second cryptosystem, we employ an elliptic curve encryption whose security is equivalent to the security of the RSA encryption, where the former achieves shorter key size than the latter. We write down concrete values of parameters for a realization of the embedding..
301. Yang Xiang, Kouichi Sakurai, Message from the workshop/symposium chairs
TrustCom 2014, Quaternary International, 10.1109/TrustCom.2014.141, xx, 2015.01.
302. Junpei Kawamoto, Kouichi Sakurai, Privacy-aware cloud-based input method editor, 2014 IEEE/CIC International Conference on Communications in China, ICCC 2014 2014 IEEE/CIC International Conference on Communications in China, ICCC 2014, 10.1109/ICCChina.2014.7008273, 209-213, 2015.01, Cloud services are useful but privacy concerns are the most important problems of them. In this paper, we focus cloud-based input method editors and introduce a privacy-aware framework of them. Input method editor (IME) is a kind of software to help us to input Japanese, Chinese, Korean, etc. It receives input words consists of alphabets and returns transformed words consists of Kanji in Japanese, etc. We assume to deploy this IME on a cloud server. In this case, input words received IME may include people's sensitive information e.g. credit card number. We employ a seachable encryption scheme and introduce a framework that people send encrypted inputs and IME computes transformed words without decrypting them..
303. Kuo Yan Wu, Kuo Y. Tsai, Tzong Che Wu, Kouichi Sakurai, Provably secure anonymous authentication scheme for roaming service in global mobility networks, Journal of Information Science and Engineering, 31, 2, 727-742, 2015.01, This paper presents an anonymous authentication scheme for roaming service in global mobility networks, in which the foreign agent cannot obtain the identity information of the mobile user who is sending the roaming request. In addition, the home agent does not have to maintain any verification table for authenticating the mobile user. We give formal analyses to show that our proposed scheme satisfies the security requirements of user anonymity, mutual authentication, session-key security, and perfect forward secrecy. Besides, some possible attacks on the proposed scheme are discussed, such as the replay attack, the man-in-middle attack, the impersonation attack, and the insider attack..
304. Pinaki Sarkar, Priyatosh Mahish, Morshed Uddin Chowdhury, Kouichi Sakurai, Securing sensor networks by moderating frequencies, 10th International Conference on Security and Privacy in Communication Networks, SecureComm 2014 International Conference on Security and Privacy in Communication Networks - 10th International ICST Conference, SecureComm 2014, Revised Selected Papers, 10.1007/978-3-319-23802-9_15, 153, 173-185, 2015.01, Security of Wireless Sensor Network (WSN) is a key issue in information security. Most existing security protocols exploit various Mathematical tools to strengthen their security. Some protocols use the details of the geographical location of the nodes. However, to the best authors’ knowledge, none of the existing works exploit the constraints faced by the adversary, specifically, tracing a particular frequency from a large range of unknown frequency channels. The current work uses positional details of the individual nodes. Then the aim is to exploit this weakness of tracing frequencies by assigning a wide range of frequency channels to each node. Experiments using Magneto Optic Sensors reveal that any change of the parametric Faraday’s rotational angle affects the frequency of the Optical waves. This idea can perhaps be generalized for practically deployable sensors (having respective parameters) along with a suitable key management scheme..
305. Kouichi Sakurai, Special section on cryptography and information security, IEICE Transactions on Fundamentals of Electronics, Communications and Computer Sciences, E98A, 1, 1-2, 2015.01.
306. Yaokai Feng, Yoshiaki Hori, Kouichi Sakurai, A proposal for detecting distributed cyber-attacks using automatic thresholding, 10th Asia Joint Conference on Information Security, AsiaJCIS 2015 Proceedings - 2015 10th Asia Joint Conference on Information Security, AsiaJCIS 2015, 10.1109/AsiaJCIS.2015.22, 152-159, 2015, Distributed attacks have reportedly caused the most serious losses in the modern cyber environment. Thus, how to avoid and detect distributed attacks has become one of the most important topics in the cyber security community. Of many approaches for avoiding and detecting cyber-attacks, behavior based method has been attracting great attentions from many researchers and developers. It is well known that, for behavior based cyber-attack detections, the algorithm for extracting normal modes from historic traffic is critically important. In this paper, after the newest algorithms for extracting normal behavior mode from historic traffics are discussed, a novel algorithm is proposed. Its efficiency is examined by experiments using darknet traffic data..
307. Hirokazu Ishizuka, Isao Echizen, Keiichi Iwamura, Kouichi Sakurai, Evaluation of a zero-watermarking-type steganography, Lecture Notes in Computer Science, 10.1007/978-3-319-19321-2_47, 9023, 613-624, 2015, We evaluated the resistance of image compression for the zero-watermarking-type steganography which proposed by us in 2005. As a result, even if we compressed to 1/100 of an original image, it still can extract its watermark information with an accuracy of 99% or more. We also proposed a new type of sparse filtering for low-frequency spatial extraction, and confirmed its performance by computational experiments. Finally, we mentioned a study on the relevance of the proposed filter and biological visual systems..
308. Nobuyuki Teraura, Kunio Ito, Daisuke Kobayashi, Kouichi Sakurai, Evaluation of gamma ray durability and its application of shielded RF tags, 23rd International Conference on Nuclear Engineering: Nuclear Power - Reliable Global Energy, ICONE 2015 ICONE 2015 - 23rd International Conference on Nuclear Engineering: Nuclear Power - Reliable Global Energy, 2015-January, 2015, In this study, the RF (Radio Frequency) tag with radiation shield is developed and its gamma ray durability is evaluated. RFID (RF Identification) is a radio-wave-based identification technology that can be used for various items. RF tags find use in many applications, including item tracing, access control, etc. RF tags can be classified as active RF tags, which have inbuilt voltaic cells, and passive RF tags without these cells. Passive RF tags, known for their low price and durability, are used in various fields. For instance, they are used for equipment maintenance in factories and thermal power plants. Several frequencies are used for RF tags. Further, RF tagging on the UHF (Ultra High Frequency) frequencies allows a communication range of approximately 10 m, and thus, remote reading is possible. When used in radiation environments such as in nuclear power plants, remote reading can contribute to the reduction of radiation exposure. However, because semiconductors are the primary elements used in the manufacture of RF tags, they can be damaged by radiation, and operational errors can occur. Therefore, this technology has not been used in environments affected by relatively high radiation levels. Therefore, in nuclear power plants, the use of RF tags is limited in areas of low radiation levels. In our study, we develop and manufacture a new RF tag with a radiation shield cover that provides error correction functionality. It is expected that radiation shielded RF tags will improve the radiation-proof feature, and its application range will be expanded. Using the radiation-proof RF tag, we have conducted radiation durability tests. These tests are of two types: one using low energy gamma ray, and the other using high-energy gamma ray. Experimental results are then analyzed. The number of applications for radiation shielded RF tags is considerably increasing, because it can be used in various radiation environments other than nuclear power plants as well, such as spent nuclear fuel storage facilities, decommissioning sites of nuclear power plants, and for decontamination operations management around Fukushima area..
309. Angsuman Das, Avishek Adhikari, Kouichi Sakurai, Plaintext checkable encryption with designated checker, Advances in Mathematics of Communications, 10.3934/amc.2015.9.37, 9, 1, 37-53, 2015, This paper introduces a new public-key primitive called designated plaintext checkable encryption (DPCE) in which given a ciphertext, a delegated checker can determine whether the ciphertext decrypts under the same public key to a plaintext chosen by himself. Motivated by various applications, two types of DPCE (of Type-I and II) are defined, depending upon whether the user delegates the plaintext checking right at his will to a delegated checker (Type-I) or the user is required to provide this plaintext checking right to a designated checker (Type-II). We propose several generic random-oracle and standard model constructions for DPCE of both the types based on arbitrary probabilistic or deterministic encryption schemes..
310. Shinichi Matsumoto, Yuya Onitsuka, Junpei Kawamoto, Kouichi Sakurai, Reconstructing and visualizing evidence of artifact from firefox sessionstorage, 15th International Workshop on Information Security Applications, WISA 2014 Information Security Applications - 15th International Workshop, WISA 2014, Revised Selected Papers, 10.1007/978-3-319-15087-1_7, 8909, 83-94, 2015, Importance of digital forensics is expected to increase in the future. Many of researches on digital forensics are targeted to persistent memory. These researches concerns about the extraction of evidence directly or via filesystem. On the other hand, there is a movement to employ the Web browser supports HTML5 as software platform. In this situation, it is considered that the forensics techniques for extracting evidences from HTML5 browser is important. In this paper, we experimented to retrieve the artifacts left by Web- Storage feature for the Web browser for personal computer from the file system. In addition, we implemented a tool that constructs and visualizes the evidence from the artifacts..
311. Hirokazu Ishizuka, Isao Echizen, Keiichi Iwamura, Kouichi Sakurai, A zero-watermarking-like steganography and potential applications, 10th International Conference on Intelligent Information Hiding and Multimedia Signal Processing, IIH-MSP 2014 Proceedings - 2014 10th International Conference on Intelligent Information Hiding and Multimedia Signal Processing, IIH-MSP 2014, 10.1109/IIH-MSP.2014.121, 459-462, 2014.12, We propose a new steganographic method which is similar to zero-watermarking. In general, digital steganography and digital watermarking, which both embed secret information in host data, have different intended uses. Digital steganography carries embedded secret information through public networks, and the host data serves only as camouflage. Digital watermarking is used to protect host data by embedding secret information. However, the concept of zero-watermarking was proposed in 2001. It does not embed secret information in host data and a result obtained by the interaction of secret information and host data is registered into a certificate authority for protecting the of host data. Our method is also intended to be included in the concept of zero-watermarking broadly. In this paper, we will clarify the difference of zerowatermarking and our method, evaluate the noise immunity of our method, and discuss with various application possibilities..
312. Nobuyuki Teraura, Kouichi Sakurai, Evaluation of the identity and compatibility of multi-valued cells in two-dimensional codes using smartphones, 7th IEEE International Conference on Service-Oriented Computing and Applications, SOCA 2014 Proceedings - IEEE 7th International Conference on Service-Oriented Computing and Applications, SOCA 2014, 10.1109/SOCA.2014.17, 252-259, 2014.12, Data is connected to the internet with a sensor for understanding the property of the thing for which a two-dimensional code was used. Two-dimensional codes can play the role of connecting cyberspace to physical space, and can play a significant role in the so-called Internet of Things. Moreover, the advancement of machine vision is progressing with machine-to-machine communication. On the other hand, there is also private information, such as personal information, that should not be known by others. Current two-dimensional codes have become ubiquitous and express the cell using two colors: white and black. The cell expresses white or black in one bit, and there is no confidentiality available. In response to this, we propose an addition to the existing part that can be read with conventional equipment. We propose a 'secrecy part' that cannot be read without a decryption key. Further, we propose a method for rendering these two-dimensional codes compatible with black-and-white codes. In order to generate the secrecy part, it is necessary to transform a cell into several bits. A multicolor method and a multiple-region method are used to transform the code into several bits. An evaluation of the multi-valued cells in the two-dimensional codes here proposed, with a read verification and compatibility along with the added secrecy part, was carried out using a smartphone with successful results..
313. Yoshifumi Ueshige, Kouichi Sakurai, Towards "receipt-freeness" in remote biometric authentication, 5th International Conference on Emerging Security Technologies, EST 2014 Proceedings - 2014 International Conference on Emerging Security Technologies, EST 2014, 10.1109/EST.2014.22, 8-12, 2014.12, Recently, cancelable biometrics, zero-bio, PKI with biometrics, and some related methods have been proposed as remote biometrics. These proposals are discussed in the viewpoint of not forensics but privacy protection. When forensic techniques are abused on the remote biometric authentication systems by third person, he/she can collect information of authentication process, such as stored templates, intermediate calculated data and etc. This situation causes novel privacy issues about excessive collection of information. Therefore, we define "receipt-freeness" of biometric authentication protocol, from the viewpoint of anti-forensics. As a first step for considering requirements for "receipt-freeness" remote biometric protocols, some related works are analyzed about characteristic of "receipt-freeness." As a result, we show the all protocols do not satisfy "receipt-freeness" except a few situations since the servers of these protocols remain some evidence such as transformed biometric data..
314. Yuto Nakano, Shinsaku Kiyomoto, Yutaka Miyake, Kouichi Sakurai, Comparison of access pattern protection schemes and proposals for efficient implementation, IEICE Transactions on Information and Systems, 10.1587/transinf.2013THP0007, E97D, 10, 2576-2585, 2014.10, Oblivious RAM (ORAM) schemes, the concept introduced by Goldreich and Ostrovsky, are very useful technique for protecting users' privacy when storing data in remote untrusted servers and running software on untrusted systems. However they are usually considered impractical due to their huge overhead. In order to reduce overhead, many improvements have been presented. Thanks to these improvements, ORAM schemes can be considered practical on cloud environment where users can expect huge storage and high computational power. Especially for private information retrieval (PIR), some literatures demonstrated they are usable. Also dedicated PIRs have been proposed and shown that they are usable in practice. Yet, they are still impractical for protecting software running on untrusted systems. We first survey recent researches on ORAM and PIR. Then, we present a practical software-based memory protection scheme applicable to several environments. The main feature of our scheme is that it records the history of accesses and uses the history to hide the access pattern. We also address implementing issues of ORAM and propose practical solutions for these issues..
315. Takanori Yasuda, Tsuyoshi Takagi, Kouichi Sakurai, Efficient variant of Rainbow using sparse secret keys, Journal of Wireless Mobile Networks, Ubiquitous Computing, and Dependable Applications, 5, 3, 3-13, 2014.09, Multivariate Public Key Cryptosystems (MPKC) is one of candidates for post-quantum cryptography. Rainbow is an MPKC digital signature scheme, with relatively efficient encryption and decryption processes. However, the size of the secret key of Rainbow is substantially larger than that of an RSA cryptosystem for the same security level. By using sparse secret keys, the size of the secret key of Rainbow can be reduced. In addition, a method using sparse secret keys can accelerate the signature generation of Rainbow. Matrix-based Rainbow and NT-Rainbow, which we previously proposed, are variants of Rainbow using sparse secret keys. These two variants of Rainbow reduce the size of the secret key of Rainbow, and improve the efficiency of the signature generation of Rainbow. In this paper, we combine these two variants of Rainbow. As a consequence, the combined scheme realizes even smaller size of the secret key and even more efficient signature generation than those of the two variants of Rainbow. In particular, in comparison with the original Rainbow, the secret key is reduced in size by about 76% and the signature generation is sped up by about 55% at the security level of 100 bits..
316. Trent Jaeger, Kouichi Sakurai, Shiho Moriai, Welcome to ASIACCS 2014!, Quaternary International, iii, 2014.06.
317. Can Wang, Yaokai Feng, Junpei Kawamoto, Yoshiaki Hori, Kouichi Sakurai, A parameterless learning algorithm for behavior-based detection, 2014 9th Asia Joint Conference on Information Security, AsiaJCIS 2014 Proceedings - 2014 9th Asia Joint Conference on Information Security, AsiaJCIS 2014, 10.1109/AsiaJCIS.2014.29, 11-18, 2014.01, The frequency and the extent of damages caused by network attacks have been actually increasing greatly in recent years, although many approaches to avoiding and detecting attacks have been proposed in the community of network security. Thus, how to fast detect actual or potential attacks has become an urgent issue. Among the detection strategies, behavior-based ones, which use normal access patterns learned from reference data (e.g., History traffic) to detect new attacks, have attracted attention from many researchers. In each of all such strategies, a learning algorithm is necessary and plays a key role. Obviously, whether the learning algorithm can extract the normal behavior modes properly or not directly influence the detection result. However, some parameters have to determine in advance in the existing learning algorithms, which is not easy, even not feasible, in many actual applications. For example, even in the newest learning algorithm, which called FHST learning algorithm in this study, two parameters are used and they are difficult to be determined in advance. In this study, we propose a parameter less learning algorithm for the first time, in which no parameters are used. The efficiency of our proposal is verified by experiment. Although the proposed learning algorithm in this study is designed for detecting port scans, it is obviously able to be used to other behavior-based detections..
318. Shinichi Matsumoto, Kouichi Sakurai, Acquisition of evidence of web storage in HTML5 web browsers from memory image, 2014 9th Asia Joint Conference on Information Security, AsiaJCIS 2014 Proceedings - 2014 9th Asia Joint Conference on Information Security, AsiaJCIS 2014, 10.1109/AsiaJCIS.2014.30, 148-155, 2014.01, Web browser is a growing platform for the execution of various applications. There are large fractions of smartphone platforms that support the execution of web technology based application, especially one such as HTML 5. However there are also some emerging smartphone platforms that only support web technology based applications. Taking into the considerations of these situations may lead to a higher importance of forensic investigations on artifacts within the web browser bringing about the usefulness of the HTML5 specific attributes as evidences in mobile forensics. Through this paper, we explore the results of experiments that acquire the main memory image within terminal and extract the webStorage data as an evidence of the browsing activity. The memory forensics of web browsing activity is highly concerned. The evidences gathered from the HTML5 web Storage contents acquired from the main memory image are examined and the results of the observations indicate the ability to retrieve web Storage from the memory image is certain. Therefore, we proclaimed formats of evidences that are retrievable from the main memory. The formats were different depending on the type of web browser accessed. Three most utilized web browsers are experimented in this paper namely, Google Chrome, Mozilla Firefox and Microsoft Internet Explorer. The results showed that the acquisition of web Storage content on the browsers were possible and elucidated its formats. Values of web Storage is contained in the residuals that left by all of three web browsers. Therefore, if the investigator has the knowledge of values, he will be able to find the location of the evidence to hint values. If the investigator does not have the knowledge about the value, then he can explore the evidence based on the knowledge of the origin or key. Because the format of the evidence depends on Web browser, investigator must use different search techniques according to the Web browser..
319. Rimba Whidiana Ciptasari, Kyung Hyune Rhee, Kouichi Sakurai, An enhanced audio ownership protection scheme based on visual cryptography, Eurasip Journal on Information Security, 10.1186/1687-417X-2014-2, 2014, 2014.01, Recently, several ownership protection schemes which combine encryption and secret sharing technology have been proposed. To reveal the original message, however, they exploited XOR operation which is similar to a one-time pad. It is fairly losing the reconstruction simplicity due to the human visual system (HVS). It should be noted that it is completely different from the original concept of visual cryptography proposed by Naor and Shamir. To decrypt the secret message, Naor and Shamir's concept stacked k transparencies together. The operation solely does a visual OR of the shares rather than XOR, the way HVS does. In this paper, we, consequently, adopt Naor and Shamir's concept to apply correct theory of visual cryptography. Furthermore, audio copyright protection schemes which exploit chaotic modulation or watermark integration into frequency components have been widely proposed. Nevertheless, security issue against intentional distortions has not been addressed yet. In this paper, we aim to construct a resilient audio ownership protection scheme to enhance the security by integrating the discrete wavelet transform and discrete cosine transform, visual cryptography, and digital timestamps. In the proposed scheme, the watermark does not require to be embedded within the original audio but is used to generate a secret image and a public image. The watermark is then acquired by performing OR between the secret and public image. We can alleviate the trade-off expenses between the capacity of data payload and two other important properties such as imperceptibility and robustness without modifying the original audio signals. The experiments against a variety of audio signals processing provided by StirMark confirm superior robustness of the proposed scheme. We also demonstrate the intentional distortion by modifying the original content via experiments, it reveals comparable reliability. The proposed scheme can be widely applied to the area of audio ownership protection..
320. Hiroaki Anada, Seiko Arita, Kouichi Sakurai, Attribute-based signatures without pairings via the Fiat-Shamir paradigm, 2nd ACM Asia Public-Key Cryptography Workshop, AsiaPKC 2014 ASIAPKC 2014 - Proceedings of the 2nd ACM Workshop on ASIA Public-Key Cryptography, 10.1145/2600694.2600696, 49-58, 2014.01, We propose the first practical attribute-based signature (ABS) scheme with attribute privacy without pairings in the random oracle model. Our strategy is in the Fiat-Shamir paradigm; we first provide a generic construction of a boolean proof system of Σ-protocol type. Our boolean proof system is a generalization of the well-known OR-proof system; that is, it can treat any boolean formula instead of a single OR-gate. Then, by combining our boolean proof system with a credential bundle scheme of the Fiat-Shamir signature, we obtain a generic attribute-based identification (ABID) scheme of proof of knowledge. Finally, we apply the Fiat-Shamir transform to our ABID scheme to obtain a generic ABS scheme which possesses attribute privacy and can be proved to be secure in the random oracle model. Our ABS scheme can be constructed without pairings..
321. Takanori Yasuda, Tsuyoshi Takagi, Kouichi Sakurai, Efficient variant of rainbow without triangular matrix representation, 2nd IFIP TC5/8 International Conference on Information and Communication Technology, ICT-EurAsia 2014 Information and Communication Technology - Second IFIP TC5/8 International Conference, ICT-EurAsia 2014, Proceedings, 10.1007/978-3-642-55032-4_55, 8407 LNCS, 532-541, 2014.01, Multivariate Public Key Cryptosystems (MPKC) is one of candidates for post-quantum cryptography. Rainbow is an MPKC digital signature scheme, with relatively efficient encryption and decryption processes. However, the size of MPKC key is substantially larger than that of an RSA cryptosystem for the same security level. In this paper, we propose a variant of Rainbow that has a smaller secret key. The smaller secret key is to the result of a different description of the quadratic polynomials appearing in the secret key from that of the original Rainbow. In addition, our scheme improves the efficiency of the Rainbow's signature generation. In particular, the secret key is reduced in size by about 40% and the signature generation is sped up by about 30% at the security level of 100 bits..
322. Yuto Nakano, Kazuhide Fukushima, Shinsaku Kiyomoto, Tsukasa Ishiguro, Yutaka Miyake, Toshiaki Tanaka, Kouichi Sakurai, Fast implementation of Kcipher-2 for software and hardware, IEICE Transactions on Information and Systems, 10.1587/transinf.E97.D.43, E97-D, 1, 43-52, 2014.01, KCipher-2 is a word-oriented stream cipher and an ISO/IEC 18033 standard. It is listed as a CRYPTREC cryptographic algorithm for Japanese governmental use. It consists of two feedback shift registers and a non-linear function. The size of each register in KCipher-2 is 32 bits and the non-linear function mainly applies 32-bit operations. Therefore, it can be efficiently implemented as software. SNOW-family stream ciphers are also word-oriented stream ciphers, and their high performance has already been demonstrated. We propose optimised implementations of KCipher-2 and compare their performance to that of the SNOW-family and other eSTREAM portfolios. The fastest algorithm is SNOW 2.0 and KCipher-2 is the second fastest despite the complicated irregular clocking mechanism. However, KCipher-2 is the fastest of the feasible algorithms, as SNOW 2.0 has been shown to have a security flaw. We also optimise the hardware implementation for the Virtex-5 field-programmable gate array (FPGA) and show two implementations. The first implementation is a rather straightforward optimisation and achieves 16,153 Mbps with 732 slices. In the second implementation, we duplicate the non-linear function using the structural advantage of KCipher-2 and we achieve 17,354 Mbps with 813 slices. Our implementation of KCipher-2 is around three times faster than those of the SNOW-family and efficiency, which is evaluated by "Throughput/Area (Mbps/slice)", is 3.6-times better than that of SNOW2.0 and 8.5-times better than that of SNOW3G. These syntheses are performed using Xilinx ISE version 12.4..
323. Shengli Liu, Kouichi Sakurai, Jian Weng, Fangguo Zhang, Yunlei Zhao, Yunlei Zhao, Security model and analysis of fhmqv, Revisited, 9th China International Conference on Information Security and Cryptology, Inscrypt 2013 Information Security and Cryptology - 9th International Conference, Inscrypt 2013, Revised Selected Papers, 10.1007/978-3-319-12087-4_16, 255-269, 2014.01, HMQV is one of the most efficient (provably secure) authenticated key-exchange protocols based on public-key cryptography, and is widely standardized. In spite of its seemingly conceptual simplicity, the HMQV protocol was actually very delicately designed. The provable security of HMQV is conducted in the Canetti-Krawczyk framework (CK-framework, in short), which is quite complicated and lengthy with many subtleties actually buried there. However, lacking a full recognition of the precise yet subtle interplay between HMQV protocol structure and provable security can cause misunderstanding of the HMQV design, and can cause potential flawed design and analysis of HMQV protocol variants. In this work, we explicitly make clear the interplay between HMQV protocol structure and provable security, showing the delicate design of HMQV. We then re-examine the security model and analysis of a recently proposed HMQV protocol variant, specifically, the FHMQV protocol proposed by Sarr et al. in [25]. We clarify the relationship between the traditional CK-framework and the CK-FHMQV security model proposed for FHMQV, and show that CK-HMQV and CK-FHMQV are incomparable. Finally, we make a careful investigation of the CDH-based analysis of FHMQV in the CK-FHMQV model, which was considered to be one of the salient advantages of FHMQV. We identify that the CDH-based security analysis of FHMQV is actually flawed. The flaws identified in the security proof of FHMQV just stem from lacking a full realization of the precise yet subtle interplay, as clarified in this work, between HMQV protocol structure and provable security..
324. Takanori Yasuda, Tsuyoshi Takagi, Kouichi Sakurai, Security of multivariate signature scheme using non-commutative rings?, IEICE Transactions on Fundamentals of Electronics, Communications and Computer Sciences, 10.1587/transfun.E97.A.245, E97-A, 1, 245-252, 2014.01, Multivariate Public Key Cryptosystems (MPKC) are candidates for post-quantum cryptography. Rainbow is a digital signature scheme in MPKC, whose signature generation and verification are relatively efficient. However, the security of MPKC depends on the difficulty in solving a system of multivariate polynomials, and the key length of MPKC becomes substantially large compared with that of RSA cryptosystems for the same level of security. The size of the secret and public keys in MPKC has been reduced in previous research. The NC-Rainbow is a signature scheme in MPKC, which was proposed in order to reduce the size of secret key of Rainbow. So far, several attacks against NC-Rainbow have been proposed. In this paper, we summarize attacks against NC-Rainbow, containing attacks against the original Rainbow, and analyze the total security of NC-Rainbow. Based on the cryptanalysis, we estimate the security parameter of NC-Rainbow at the several security level. Copyright c.
325. Ji Jian Chin, Hiroaki Anada, Seiko Arita, Kouichi Sakurai, Swee Huay Heng, Raphael Phan, Survey and new idea for attribute-based identification scheme secure against reset attacks, 4th International Cryptology and Information Security Conference 2014, Cryptology 2014 Conference Proceedings - Cryptology 2014 Proceedings of the 4th International Cryptology and Information Security Conference 2014, 39-47, 2014.01, Identification schemes are a common one-way authentication technique for a user to prove himself securely to a verifier. However, it is known that identification schemes based on the sigma-protocol are basically insecure against reset attacks. On the other-hand, attribute-based cryptography is a technique which allows for the secure implementation of access policies within a cryptosystem. In this paper, we report on the developments in the area of reset attacks for identification schemes as well as for attribute-based identification schemes. Then we put together a new idea to construct attribute-based identification schemes secure against reset attacks..
326. Motoki Kitahara, Junpei Kawamoto, Kouichi Sakurai, A Method of Digital Rights Management based on Bitcoin Protocol, 8th International Conference on Ubiquitous Information Management and Communication, ICUIMC 2014 Proceedings of the 8th International Conference on Ubiquitous Information Management and Communication, ICUIMC 2014, 10.1145/2557977.2558034, 2014, In the digital world, so many copyrighted works are made in an illegal way because it is easy to keep and copy. Digital Rights Management has proposed to prevent this theft. Contents providers often bring in one server who has charge of managing the normal user, but there are some problems that it flocks to the server. Against this problem, P2P based DRM system has considered. All users can transfer the encrypted content to other users, so the content server does not have to load so much traffic from users. As a problem with this method, it is hard to figure out usage situation of contents because P2P based system is divided into many pieces of users. In this paper, we propose a new P2P based DRM system using Bitcoin protocol, which is one of the electric commerce. Bitcoin protocol, timestamp server saves all transactions to prevent double spending. We can bring out all usage situations to apply this system..
327. Morshed Chowdhury, Jemal Abawajy, Andrei Kelarev, Kouichi Sakurai, A competitive three-level pruning technique for information security, Communications in Computer and Information Science, 10.1007/978-3-662-45670-5, 490, 25-32, 2014, The reduction of size of ensemble classifiers is important for various security applications. The majority of known pruning algorithms belong to the following three categories: ranking based, clustering based, and optimization based methods. The present paper introduces and investigates a new pruning technique. It is called a Three-Level Pruning Technique, TLPT, because it simultaneously combines all three approaches in three levels of the process. This paper investigates the TLPT method combining the state-of-the-art ranking of the Ensemble Pruning via Individual Contribution ordering, EPIC, the clustering of the K-Means Pruning, KMP, and the optimisation method of Directed Hill Climbing Ensemble Pruning, DHCEP, for a phishing dataset. Our new experiments presented in this paper show that the TLPT is competitive in comparison to EPIC, KMP and DHCEP, and can achieve better outcomes. These experimental results demonstrate the effectiveness of the TLPT technique in this example of information security application..
328. Partha Sarathi Roy, Avishek Adhikari, Rui Xu, Kirill Morozov, Kouichi Sakurai, An efficient robust secret sharing scheme with optimal cheater resiliency, 4th International Conference on Security, Privacy, and Applied Cryptography Engineering, SPACE 2014 Security, Privacy, and Applied Cryptography Engineering - 4th International Conference, SPACE 2014, Proceedings, 8804, 47-58, 2014, In this paper, we consider the problem of (t, δ) robust secret sharing secure against rushing adversary. We design a simple t-out-ofn secret sharing scheme, which can reconstruct the secret in presence of t cheating participants except with probability at most δ, provided t < n/2. The later condition on cheater resilience is optimal for the case of public reconstruction of the secret, on which we focus in this work. Our construction improves the share size of Cevallos et al. (EUROCRYPT-2012) robust secret sharing scheme by applying the “authentication tag compression” technique devised by Carpentieri in 1995. Our improvement is by a constant factor that does not contradict the asymptotic near-optimality of the former scheme. To the best of our knowledge, the proposed scheme has the smallest share size, among other efficient rushing (t, δ) robust secret sharing schemes with optimal cheater resilience..
329. Chunhua Su, Jianying Zhou, Feng Bao, Tsuyoshi Takagi, Kouichi Sakurai, Collaborative agglomerative document clustering with limited information disclosure, Security and Communication Networks, 10.1002/sec.811, 7, 6, 964-978, 2014, Document clustering is a practical and powerful data mining technique to analyze large amount of documents and large sets of text or hypertext documents. However, it also brings the problem of sensitive information leaking in disregard of privacy, especially when it is executed in distributed environment. In this paper, we propose a cryptography-based framework to realize privacy-preserving document clustering among the users under the distributed environment; there are two parties, each having his private document database, want to collaboratively execute agglomerative document clustering without disclosing their private contents. We provide two implementations of such a framework, one is with more precision and stronger security but requires more computational resources. The other is a simplified version with less computational complexity and achieves higher processing speed. Additionally, we provide the security proofs and experimental analysis of precision and scalability of our proposal..
330. Fangming Zhao, Takashi Nishide, Kouichi Sakurai, Fine-grained access control aware multi-user data sharing with secure keyword search, IEICE Transactions on Information and Systems, 10.1587/transinf.E97.D.1790, E97-D, 7, 1790-1803, 2014, We consider the problems of access control and encrypted keyword search for cryptographic cloud storage in such a way that they can be implemented for a multiple users setting. Our fine-grained access control aware multi-user secure keyword search approach interdependently harmonizes these two security notions, access control and encrypted keyword search. Owing to the shrinkage of the cloud server's search space to the user's decryptable subset, the proposed scheme both decreases information leakage and is shown to be efficient by the results of our contrastive performance simulation..
331. Yanjiang Yang, Haibing Lu, Jian Weng, Youcheng Zhang, Kouichi Sakurai, Fine-grained conditional proxy re-encryption and application, 21st International Conference on Neural Information Processing, ICONIP 2014 Provable Security - 8th International Conference, ProvSec 2014, Proceedings, 8782, 206-222, 2014, Conditional proxy re-encryption (CPRE) enables delegation of decryption rights, and is useful in many applications. In this paper, we present a ciphertext-policy attribute based CPRE scheme, together with a formalization of the primitive and its security proof. We further propose applying the scheme for fine-grained encryption of cloud data. This application well implements the idea of cloud-enabled user revocation, offering an alternative yet more feasible solution to the user revocation issue when using attribute based encryption over cloud data. Features of the application include little cost in case of user revocation, and high user-side efficiency when users access cloud data..
332. Satoshi Tanaka, Takanori Yasuda, Kouichi Sakurai, Implementation of efficient operations over GF(232) using graphics processing units, 2nd IFIP TC5/8 International Conference on Information and Communication Technology, ICT-EurAsia 2014 Information and Communication Technology - Second IFIP TC5/8 International Conference, ICT-EurAsia 2014, Proceedings, 10.1007/978-3-642-55032-4_62, 8407 LNCS, 602-611, 2014, Evaluating non-linear multivariate polynomial systems over finite fields is an important subroutine, e.g., for encryption and signature verification in multivariate public-key cryptography. The security of multivariate cryptography definitely becomes lower if a larger field is used instead of GF(2) given the same number of bits in the key. However, we still would like to use larger fields because multivariate cryptography tends to run faster at the same level of security if a larger field is used. In this paper, we compare the efficiency of several techniques for evaluating multivariate polynomial systems over GF(232) via their implementations on graphics processing units..
333. Wataru Tsuda, Yoshiaki Hori, Kouichi Sakurai, Performance evaluation of information theoretic secure multi-channel transmission on multihop wireless network, 2013 IEEE 8th International Conference on Broadband, Wireless Computing, Communication and Applications, BWCCA 2013 Proceedings - 2013 8th International Conference on Broadband, Wireless Computing, Communication and Applications, BWCCA 2013, 10.1109/BWCCA.2013.99, 570-574, 2013.12, Current mainstream encryption based on computational security is sufficiently safe. However, if the computing power of an adversary increases, current encryption methods may no longer be safe. In this study, we focus on PSMT (Perfectly Secure Message Transmission) which is based on information theoretic security which could establish a security level stronger than computational security. We evaluated the performance of information theoretic secure Multi-channel Transmission on wireless sensor networks..
334. Takanori Yasuda, Tsuyoshi Takagi, Kouichi Sakurai, Multivariate signature scheme using quadratic forms, 5th International Workshop on Post-Quantum Cryptography, PQCrypto 2013 Post-Quantum Cryptography - 5th International Workshop, PQCrypto 2013, Proceedings, 10.1007/978-3-642-38616-9_17, 7932 LNCS, 243-258, 2013.09, Multivariate Public Key Cryptosystems (MPKC) are candidates for post-quantum cryptography. MPKC has an advantage in that its encryption and decryption are relatively efficient. In this paper, we propose a multivariate signature scheme using quadratic forms. For a finite dimensional vector space V, it is known that there are exactly two equivalence classes of non-degenerate quadratic forms over V. We utilize the method to transform any non-degenerate quadratic form into the normal form of either of the two equivalence classes in order to construct a new signature scheme in MPKC. The signature generation of our scheme is between eight and nine times more efficient more than the multivariate signature scheme Rainbow at the level of 88-bit security. We show that the public keys of our scheme can not be represented by the public keys of other MPKC signature schemes and this means our scheme is immune to many attacks that depend on the form of the central map used by these schemes..
335. Laiping Zhao, Yizhi Ren, Kouichi Sakurai, Reliable workflow scheduling with less resource redundancy, Parallel Computing, 10.1016/j.parco.2013.06.003, 39, 10, 567-585, 2013.07, We examine the problem of reliable workflow scheduling with less resource redundancy. As scheduling workflow applications in heterogeneous systems, either for optimizing the reliability or for minimizing the makespan, are NP-Complete problems, we alternatively find schedules for meeting specific reliability and deadline requirements. First, we analyze the reliability of a given schedule using two important definitions: Accumulated Processor Reliability (APR) and Accumulated Communication Reliability (ACR). Second, inspired by the reliability analysis, we present three scheduling algorithms: RR algorithm schedules least Resources to meet the Reliability requirement; DRR algorithm extends RR by further considering the Deadline requirement; and dynamic algorithm schedules tasks dynamically: It avoids the "Chain effect" caused by uncertainties on the task execution time estimates, and relieves the impact from the inaccuracy on failure estimation. Finally, the empirical evaluation shows that our algorithms can save a significant amount of computation and communication resources when performing a similar reliability compared to Fault-Tolerant-Scheduling-Algorithm (FTSA) algorithm..
336. Takanori Yasuda, Jintai Ding, Tsuyoshi Takagi, Kouichi Sakurai, A variant of rainbow with shorter secret key and faster signature generation, 1st ACM Workshop on Asia Public-Key Cryptography, AsiaPKC 2013 AsiaPKC 2013 - Proceedings of the 1st ACM Workshop on Asia Public-Key Cryptography, 10.1145/2484389.2484401, 57-62, 2013.05, Multivariate public key cryptosystems are being focused on as candidates for post-quantum cryptography. Rainbow is one of the most efficient signature schemes in multivariate public key cryptosystems. The main drawback of Rainbow is that their key size is much larger than that of RSA and ECC. In this paper, we propose an efficient variant of Rainbow that has a shorter secret key (and thus generates signatures faster) than the corresponding original Rainbow. In our scheme, we divide each layer of Rainbow into smaller blocks by using diagonal matrix representations. The size of the smaller blocks can be flexibly selected, and this enables us to carefully choose secure parameters so that our proposed scheme is secure against known attacks such as rank attacks, direct attacks, and UOV attack. We estimate that the secret key size of our proposed scheme with 100-bit security is smaller by about 40% than that of the original Rainbow. In addition, an implementation of our scheme in the C language is seen to generate signature faster by 40%..
337. Motoki Kitahara, Takanori Yasuda, Takashi Nishide, Kouichi Sakurai, Upper bound of the length of information embedd in RSA public key efficiently, 1st ACM Workshop on Asia Public-Key Cryptography, AsiaPKC 2013 AsiaPKC 2013 - Proceedings of the 1st ACM Workshop on Asia Public-Key Cryptography, 10.1145/2484389.2484396, 33-38, 2013.05, Lenstra proposed a method by which information can be efficiently in a public key N in RSA encryption. Since then, many methods such as the additional key escrow function and a visible public key have been proposed. Lenstra made an assertion that the size of embeddable information is up to half the length of a public key, but he did not mention the strict upper bound of the size. In this paper, we analytially examine the Lenstra algorithm both in theory and implementation, and calcuate the upper bound of the size of information that can be efficiently embedded in an RSA public key..
338. Satoshi Tanaka, Takashi Nishide, Kouichi Sakurai, Efficient implementation for QUAD stream cipher with GPUs, Computer Science and Information Systems, 10.2298/CSIS121102040T, 10, 2 SPL, 897-911, 2013.04, QUAD stream cipher uses multivariate polynomial systems. It has provable security based on the computational hardness assumption. More specifically, the security of QUAD depends on hardness of solving non-linear multivariate systems over a finite field, and it is known as an NP-complete problem. However, QUAD is slower than other stream ciphers, and an efficient implementation, which has a reduced computational cost, is required. In this paper, we propose an efficient implementation of computing multivariate polynomial systems for multivariate cryptography on GPU and evaluate efficiency of the proposal. GPU is considered to be a commodity parallel arithmetic unit. Moreover, we give an evaluation of our proposal. Our proposal parallelizes an algorithm of multivariate cryptography, and makes it efficient by optimizing the algorithm with GPU..
339. Fangming Zhao, Takashi Nishide, Yoshiaki Hori, Kouichi Sakurai, Analysis of methods for detecting compromised nodes and its countermeasures, International Conference on IT Convergence and Security, ICITCS 2012 IT Convergence and Security 2012, 10.1007/978-94-007-5860-5_7, 215 LNEE, 53-60, 2013.02, The increased application of sensor network introduces new security challenges. In this paper, we analyze the detection methods of compromised nodes and its countermeasure in the sensor network. We first review common attacks in the sensor network application which can compromise a valid, resource-constrained node (or called device). Then, we introduce several standard detection approaches to show their characteristics in different applications of the sensor network. Finally, we summarize and discuss existing countermeasures to the compromised nodes..
340. Jingyu Hua, Kouichi Sakurai, Botnet command and control based on Short Message Service and human mobility, Computer Networks, 10.1016/j.comnet.2012.06.007, 57, 2, 579-597, 2013.02, Many serious threats for PCs are spreading to the mobile environment. A mobile botnet, which is a collection of hijacked smartphones under the control of hackers, is one of them. With the quick development of the computing and communication abilities of smartphones, many command and control (C&C) techniques in PC botnets can be easily reused in mobile botnets. However, some particular functions and characteristics of smartphones may provide botmasters with additional means to control their mobile botnets. This paper presents two special C&C mechanisms that leverage Short Message Service and human mobility, respectively. The first one designs a SMS-based flooding algorithm to propagate commands. We theoretically prove that the uniform random graph is the optimal topology for this botnet, and demonstrate its high efficiency and stealth with various simulations. The second one utilizes Bluetooth to transmit botnet commands when hijacked smartphones encounter each other while in motion. We study its performance in a 100 m × 100 m square area with NS-2 simulations, and show that human-mobility characteristics facilitate the command propagation. Even if the infection rate is low, the command can still be effectively propagated provided that the mobility of devices is high. In the end, we propose effective defense strategies against these two special C&C mechanisms..
341. Yizhi Ren, Mingchu Li, Yang Xiang, Yongrui Cui, Kouichi Sakurai, Evolution of cooperation in reputation system by group-based scheme, Journal of Supercomputing, 10.1007/s11227-010-0498-8, 63, 1, 171-190, 2013.01, Reputation systems are very useful in large online communities in which users may frequently have the opportunity to interact with users with whom they have no prior experience. Recently, how to enhance the cooperative behaviors in the reputation system has become to one of the key open issues. Emerging schemes focused on developing efficient reward and punishment mechanisms or capturing the social or economic properties of participants. However, whether this kind of method can work widely or not has been hard to prove until now. Research in evolutionary game theory shows that group selection (or multilevel selection) can favor the cooperative behavior in the finite population. Furthermore, some recent works give fundamental conditions for the evolution of cooperation by group selection. In the paper, we extend the original group selection theory and propose a group-based scheme to enhance cooperation for online reputation systems. Related concepts are defined to capture the social structure and ties among participants in reputation system, e.g., group, assortativity, etc. Also, we use a Fermi distribution function to reflect the bounded rationality of participants and the existence of stochastic factors in evolutionary process. Extended simulations show that our scheme can enhance cooperation and improve the average performance of participants (e.g. payoff) in reputation system..
342. Rimba Whidiana Ciptasari, Kyung Hyune Rhee, Kouichi Sakurai, Exploiting reference images for image splicing verification, Digital Investigation, 10.1016/j.diin.2013.06.014, 10, 3, 246-258, 2013.01, At the moment, image forgery in the mainstream media has become common. The degree of manipulation is facilitated by image editing software. Hence, there are many outstanding images which have no provenance information or certainty of authenticity. Therefore, constructing a scientific and automatic way for evaluating image authenticity is an important task. In spite of having outstanding performance, all the image forensics schemes developed so far have not provided verifiable information about source of tampering. This paper aims to propose a different kind of scheme, by exploiting a group of similar images, to verify the source of tampering. We begin with slightly modifying Robert's detector to enhance the detection results. The usage of membership function used to classify the suspicious region from the authentic one is introduced as well. Inspired by the image registration concept, we exploit the correlation-based alignment method to automatically identify the spliced region in any fragment of the reference images. Although the scheme is applicable under particular conditions, the efficacy of the proposed scheme on revealing the source of spliced regions is considerable. We anticipate this scheme to be the first concrete technique toward appropriate tools which are necessary for exposing digital image forgeries..
343. Yaokai Feng, Yoshiaki Hori, Kouichi Sakurai, Junnichi Takeuchi, A behavior-based method for detecting distributed scan attacks in darknets, Journal of Information Processing, 10.2197/ipsjjip.21.527, 21, 3, 527-538, 2013, The technologies used by attackers in the Internet environment are becoming more and more sophisticated. Of the many kinds of attacks, distributed scan attacks have become one of the most serious problems. In this study, we propose a novel method based on normal behavior modes of traffic to detect distributed scan attacks in darknet environments. In our proposed method, all the possible destination TCP and UDP ports are monitored, and when a port is attacked by a distributed scan, an alert is given. Moreover, the alert can have several levels reflecting the relative scale of the attack. To accelerate learning and updating the normal behavior modes and to realize rapid detection, an index is introduced, which is proved to be very efficient. The efficiency of our proposal is verified using real darknet traffic data. Although our proposal focuses on darknets, the idea can also be applied to ordinary networks..
344. Avishek Adhikari, Kirill Morozov, Satoshi Obana, Partha Sarathi Roy, Kouichi Sakurai, Rui Xu, Efficient threshold secret sharing schemes secure against rushing cheaters, 9th International Conference on Information-Theoretic Security, ICITS 2016 Information Theoretic Security - 9th International Conference, ICITS 2016, Revised Selected Papers, 10.1007/978-3-319-49175-2_1, 10015 LNCS, 3-23, 2016.01, In this paper, we consider two very important issues namely detection and identification of k-out-of-n secret sharing schemes against rushing cheaters who are allowed to submit (possibly forged) shares after observing shares of the honest users in the reconstruction phase. Towards this, we present four different schemes. Among these, first we present two k-out-of-n secret sharing schemes, the first one being capable of detecting (k − 1)/3 cheaters such that |Vi| = |S|/∊3 and the second one being capable of detecting n − 1 cheaters such that |Vi| = |S|/∊k+1, where S denotes the set of all possible secrets, ∊ denotes the successful cheating probability of cheaters and Vi denotes set all possible shares. Next we present two k-out-of-n secret sharing schemes, the first one being capable of identifying (k−1)/3 rushing cheaters with share size |Vi| that satisfies |Vi| = |S|/∊k. This is the first scheme, whose size of shares does not grow linearly with n but only with k, where n is the number of participants. For the second one, in the setting of public cheater identification, we present an efficient optimal cheater resilient k-out-of-n secret sharing scheme against rushing cheaters having the share size |Vi| = (n−t)n+2t|S|/∊n+2t. The proposed scheme achieves flexibility in the sense that the security level (i.e., the cheater(s) success probability) is independent of the secret size. Each of the four proposed schemes has the smallest share size among the existing schemes having the mentioned properties in the respective models..
345. Nobuyuki Teraura, Kunio Ito, Daisuke Kobayashi, Kouichi Sakurai, Evaluation of gamma ray durability of RF tag and application to the radiation environment, IEEE International Conference on RFID Technology and Applications, RFID-TA 2015 2015 IEEE International Conference on RFID Technology and Applications, RFID-TA 2015, 10.1109/RFID-TA.2015.7379809, 147-152, 2016.01, As for common RF tag, the circuitry operator part is formed with the semiconductor. Then, when radiation, such as a gamma ray, is irradiated, a recoverable soft error and unrecoverable hard error will occur. Therefore, it cannot be used depending on the exposure dose of radiation. However, a radiation-proof ability can be raised by incorporating a shielding and an error correction. Then, RF tag which covered was irradiated with the gamma ray originating in Cesium 137 or Cobalt 60 grade, and the durability was evaluated. The application which uses this radiation-proof RF tag under radiation environment is proposed. They are management of the radioactive component generated from radioactive waste or a decommissioning process to improve the traceability, etc. Moreover, the evaluation result of RF tag used for management of the medical relationship instrument which performs gamma sterilization is described..
346. Hiroaki Anada, Sushmita Ruj, Kouichi Sakurai, Expressive rating scheme by signatures with predications on ratees, 10th International Conference on Network and System Security, NSS 2016 Network and System Security - 10th International Conference, NSS 2016, Proceedings, 10.1007/978-3-319-46298-1_24, 9955 LNCS, 363-379, 2016.01, Reputation boards are popular tools because of their useful information of products for consumers. In this paper, we propose a rating scheme for the reputation boards. The feature of our rating scheme is that it enables users to rate not only products but also their providers expressively by using digital signatures with predications on ratees. First, we define a syntax of such an expressive rating scheme. Then, we provide a generic conversion of a cryptographic primitive called an attributebased signature scheme (ABS) into an expressive rating scheme. Using a boolean formula on attributes of ratees, signatures with predications on ratees are generated, which we call expressive ratings. Public linkability of ABS is effectively used to prohibit double ratings. Also, employing an ABS scheme of the Fiat-Shamir type, we construct a concrete efficient expressive rating scheme..
347. Samiran Bag, Sushmita Ruj, Kouichi Sakurai, On the application of clique problem for proof-of-work in cryptocurrencies, 11th International Conference on Information Security and Cryptology, Inscrypt 2015 Information Security and Cryptology - 11th International Conference, Inscrypt 2015, Revised Selected Papers, 10.1007/978-3-319-38898-4_16, 260-279, 2016.01, In this work we propose a scheme that could be used as an alternative to the existing proof of work(PoW) scheme for mining in Bitcoin P2P network. Our scheme ensures that the miner must do at least a non-trivial amount of computation for solving the computational problem put forth in the paper and thus solving a PoW puzzle. Here, we have proposed to use the problem of finding the largest clique in a big graph as a replacement for the existing Bitcoin PoW scheme. In this paper, we have dealt with a graph having O(230) vertices and O(248) edges which is constructed deterministically using the set of transactions executed within a certain time slot. We have discussed some algorithms that can be used by any Bitcoin miner to solve the PoW puzzle. Then we discuss an algorithm that could perform this task by doing O(280) hash calculations. We have also proposed an improvement to this algorithm by which the PoW puzzle can be solved by calculating O(270.5) hashes and using O(248) space. This scheme is better than the existing proof of work schemes that use Hashcash, where a lucky miner could manage to find a solution to the proof of work puzzle by doing smaller amount of computation though it happens with very low probability. Bitcoin incentivizes the computing power of miners and hence, it is desirable that miners with more computing power always wins. Also, the Bitcoin PoW scheme only incentivizes computing power of miners but our PoW scheme incentivizes both computing power and memory of a miner. In our proposed scheme only the miner cannot randomly find a largest clique without knowing the clique number of the graph..
348. Binanda Sengupta, Samiran Bag, Kouichi Sakurai, Sushmita Ruj, Retricoin
Bitcoin based on compact proofs of retrievability, 17th International Conference on Distributed Computing and Networking, ICDCN 2016 Proceedings of the 17th International Conference on Distributed Computing and Networking, ICDCN 2016, 10.1145/2833312.2833317, 04-07-January-2016, 2016.01, Bitcoin [24] is a fully decentralized electronic cash system. The generation of the proof-of-work in Bitcoin requires large amount of computing resources. However, this huge amount of energy is wasted as one cannot make something useful out of it. In this paper, we propose a scheme called Retricoin which replaces the heavy computational proof-of-work of Bitcoin by proofs of retrievability that have practical benefits. To guarantee the availability of an important but large file, we distribute the segments of the file among the users in the Bitcoin network. Every user who wants to mine Bitcoins must store a considerable portion of this file and prove her storage to other peers in the network using proofs of retrievability. The file can be constructed at any point of time from the users storing their respective segments untampered. Retricoin is more efficient than the existing Permacoin scheme [23] in terms of storage overhead and network bandwidth required to broadcast the proof to the Bitcoin network. The verification time in our scheme is comparable to that of Permacoin and reasonable for all practical purposes. We also design an algorithm to let the miners in a group (or pool) mine collectively..
349. Samiran Bag, Kouichi Sakurai, Yet another note on block withholding attack on bitcoin mining pools, 19th Annual International Conference on Information Security, ISC 2016 Information Security - 19th International Conference, ISC 2016, Proceedings, 10.1007/978-3-319-45871-7_11, 9866 LNCS, 167-180, 2016.01, In this paper we provide a short quantitative analysis of Bit- coin Block Withholding (BWH) Attack. In this study, we investigate the incentive earned by a miner who either independently or at the diktat of a separate mining pool launches Block Withholding attack on a target mining pool. The victim pool shares its earned revenue with the rogue attacker. We investigate the property revenue function of the attacker and find parameters that could maximize the gain of the attacker. We then propose a new concept that we call “special reward”. This spe- cial rewarding scheme is aimed at discouraging the attackers by grant- ing additional incentive to a miner who actually finds a block. A BWH attacker who never submits a valid block to the pool will be deprived from this special reward and her gain will be less than her expectation. Depending upon the actual monetary value of the special reward a pool can significantly reduce the revenue of a BWH attacker and thus can even ward off the threat of an attack..
350. Mojtaba Alizadeh, Mazdak Zamani, Sabariah Baharun, Azizah Abdul Manaf, Kouichi Sakurai, Hiroaki Anada, Hassan Keshavarz, Shehzad Ashraf Chaudhry, Muhammad Khurram Khan, Erratum
Cryptanalysis and improvement of "A secure password authentication mechanism for seamless handover in proxy mobile IPv6 networks" (PLoS ONE (2015) 10:11 (e0142716) DOI:10.1371/journal.pone.0142716), PLoS One, 10.1371/journal.pone.0145975, 10, 12, 2015.12.
351. Mojtaba Alizadeh, Mazdak Zamani, Sabariah Baharun, Azizah Abdul Manaf, Kouichi Sakurai, Hiroki Anada, Hassan Keshavarz, Shehzad Ashraf Chaudhry, Muhammad Khurram Khan, Cryptanalysis and improvement of "a secure password authentication mechanism for seamless handover in proxy mobile IPv6 networks", PLoS One, 10.1371/journal.pone.0142716, 10, 11, 2015.11, Proxy Mobile IPv6 is a network-based localized mobility management protocol that supports mobility without mobile nodes' participation in mobility signaling. The details of user authentication procedure are not specified in this standard, hence, many authentication schemes have been proposed for this standard. In 2013, Chuang et al., proposed an authentication method for PMIPv6, called SPAM. However, Chuang et al.'s Scheme protects the network against some security attacks, but it is still vulnerable to impersonation and password guessing attacks. In addition, we discuss other security drawbacks such as lack of revocation procedure in case of loss or stolen device, and anonymity issues of the Chuang et al.'s scheme. We further propose an enhanced authentication method to mitigate the security issues of SPAM method and evaluate our scheme using BAN logic..
352. Takanori Yasuda, Xavier Dahan, Yun Ju Huang, Tsuyoshi Takagi, Kouichi Sakurai, A multivariate quadratic challenge toward post-quantum generation cryptography, ACM Communications in Computer Algebra, 10.1145/2850449.2850462, 49, 3, 105-107, 2015.09, Multivariate polynomials over finite fields have found applications in Public Key Cryptography (PKC) where the hardness to find solutions provides the "one-way function" indispensable to such cryptosystems. Several schemes for both encryption and signature have been proposed, many of which are using quadratic (degree 2) polynomials. Finding a solution to such systems in general is called MQ problem, which easiest "generic" instances are NP-hard. An important feature of this Multivariate Pubic Key Cryptography (MPKC) is the resistance to quantum computers: no faster quantum algorithm than classical ones to solve MQ problem is known. Besides being thereby a candidate for Post-Quantum Cryptography, signatures are much shorter than to other candidates. We have established an open public "MQ Challenge" (https://www.mqchallenge.org) to stimulate progress in the design of efficient algorithms to solve MQ problem, and thus test limit parameters guaranteeing security of MPKC..
353. Nobuyuki Teraura, Kouichi Sakurai, Proposal of multi-value cell structure for high-density two-dimensional codes and evaluation of readability using smartphones, 7th International Conference on New Technologies, Mobility and Security, NTMS 2015 2015 7th International Conference on New Technologies, Mobility and Security - Proceedings of NTMS 2015 Conference and Workshops, 10.1109/NTMS.2015.7266514, 2015.09, In the now-popular two-dimensional code, bits are expressed using white and two black colors in the cell, which forms the element. However, such codes do not have confidentiality. Since confidentiality may be needed according to the use, a large-capacity and high-density two-dimensional code with compatibility and confidentiality can be realized by adding a secrecy part in addition to the existing part. To enlarge capacity, it is necessary to form a cell using many bits, which requires a multicolor method. The read verification of the compatible area and the additional area was carried out using a smartphone, and the code was verified to confirm its practicality..
354. Takanori Yasuda, Tsuyoshi Takagi, Kouichi Sakurai, Constructing Pairing-Friendly Elliptic Curves Using Global Number Fields, 3rd International Symposium on Computing and Networking, CANDAR 2015 Proceedings - 2015 3rd International Symposium on Computing and Networking, CANDAR 2015, 10.1109/CANDAR.2015.28, 477-483, 2016.03, Efficient implementation of pairing-based cryptography requires construction of a pairing-friendly curve and its corresponding twisted curve. In this paper, we give a formula which determines the twisted curve. The formula are obtained by using technique in the algebraic number theory such as the complex multiplication theory. Applying the formula, we present an easy method for constructing pairing-friendly curves for BN-family. In fact, our method does not require the process of elliptic curve construction and finite field construction, but only requires searching an integer satisfying some conditions. Using our construction method, we implemented an optimal ate pairing for BN-family which is usable at various security levels, and investigated the time efficiency of the pairing computation for various security levels..
355. Hirokazu Ishizuka, Kouichi Sakurai, Isao Echizen, Keiichi Iwamura, Evaluation of Matching Accuracy of Template Matching Using a Steganography Algorithm, 3rd International Symposium on Computing and Networking, CANDAR 2015 Proceedings - 2015 3rd International Symposium on Computing and Networking, CANDAR 2015, 10.1109/CANDAR.2015.68, 457-462, 2016.03, The steganography that we suggested uses the data that ties strongly to the characteristics of the original image as watermark information without changing the original image. Although similarity with zero-watermarking is pointed out, the major difference is that our method does not need pre-processing for a feature extraction at decoding. Since the decoding can do at high speed, besides using as the original steganography, it is possible to apply it to similar image retrieving, similar image order sorting or template matching. For example, when applying it to medical images, a doctor is possible to pick some similar images from a medical image database and refers the treatments through the images with concealing the information of the patient. This time, we have investigated the identification accuracy of our method with respect to the template matching of similar image searching..
356. Mojtaba Alizadeh, Saeid Abolfazli, Mazdak Zamani, Sabariah Baaaharun, Kouichi Sakurai, Authentication in mobile cloud computing
A survey, Journal of Network and Computer Applications, 10.1016/j.jnca.2015.10.005, 61, 59-80, 2016.02, Mobile cloud computing (MCC) is the state-of-the-art mobile distributed computing model that incorporates multitude of heterogeneous cloud-based resources to augment computational capabilities of the plethora of resource-constraint mobile devices. In MCC, execution time and energy consumption are significantly improved by transferring execution of resource-intensive tasks such as image processing, 3D rendering, and voice recognition from the hosting mobile to the cloud-based resources. However, accessing and exploiting remote cloud-based resources is associated with numerous security and privacy implications, including user authentication and authorization. User authentication in MCC is a critical requirement in securing cloud-based computations and communications. Despite its critical role, there is a gap for a comprehensive study of the authentication approaches in MCC which can provide a deep insight into the state-of-the-art research. This paper presents a comprehensive study of authentication methods in MCC to describe MCC authentication and compare it with that of cloud computing. The taxonomy of the state-of-the-art authentication methods is devised and the most credible efforts are critically reviewed. Moreover, we present a comparison of the state-of-the-art MCC authentication methods considering five evaluation metrics. The results suggest the need for futuristic authentication methods that are designed based on capabilities and limitations of MCC environment. Finally, the design factors deemed could lead to effective authentication mechanisms are presented, and open challenges are highlighted based on the weaknesses and strengths of existing authentication methods..
357. Tomohisa Ishikawa, Kouichi Sakurai, A study of security management with cyber insurance, 10th International Conference on Ubiquitous Information Management and Communication, IMCOM 2016 ACM IMCOM 2016: Proceedings of the 10th International Conference on Ubiquitous Information Management and Communication, 10.1145/2857546.2857615, 2016.01, Since the recent security breach requires the intensification of security management, the documents, describing the best practice of security management, are published by experts. However, the implementations of all best practice are tough because of the cost and the difficulty of cost-effective security investment. This paper discusses the security management theory with cyber risk insurance, especially the effectiveness of cyber risk insurance by Monte Carlo simulation approach..
358. Misni Harjo Suwito, Shinchi Matsumoto, Junpei Kawamoto, Dieter Gollmann, Kouichi Sakurai, An analysis of IT assessment security maturity in higher education institution, International Conference on Information Science and Applications, ICISA 2016 Information Science and Applications, ICISA 2016, 10.1007/978-981-10-0557-2_69, 376, 701-713, 2016.01, The information technology (IT) has been applied widely in Indonesia Higher Education Institution for various services. Many organizations responsible for managing the IT infrastructure, however, rarely have a framework for assessing the security maturity level of their information management. The implementation of a framework is one of solutions, but has not been yet maximized. Therefore we suggest to combine several frameworks in hope that they can be complementary. The combination of different frameworks will be more effective to monitoring the security maturity level by using an assessment security maturity management. This assessment security maturity management is a combination of framework control objective from IT Governance COBIT® 4.1 (Control Objectives for Information and related Technology) with Management Service in ITIL v3 (Information Technology Infrastructure Library) and ISO/IEC 27001. Since assessment of security maturity management is measured using COBIT® 4.1 assessment framework, and before it was adjusted with the ISO 27001 framework applied maximal. This paper present the results of assessment maturity security management, mapping of combination framework providing an indicator of security maturity level at one of university in Jakarta. A case study conducted shows that combination of some frameworks to support assessment of security maturity management level becomes more effective and efficient..
359. Takanori Yasuda, Hiroaki Anada, Kouichi Sakurai, Application of NTRU using group rings to partial decryption technique, 7th International Conference on the Theory, Technologies and Applications of Trusted Systems, INTRUST 2015 Trusted Systems - 7th International Conference, INTRUST 2015, Revised Selected Papers, 10.1007/978-3-319-31550-8_13, 9565, 203-213, 2016.01, Partial decryption enables a ciphertext to be decrypted partially according to provided secret keys. In this paper, we propose a public key encryption scheme with the functionality of partial decryption. Our strategy is to use the NTRU cryptosystem. Under a design principle of the mathematical structure “group ring”, we extend the original NTRU into group ring NTRU (GR-NTRU). First, we propose a generic framework of our GR-NTRU. Our GR-NTRU allows partial decryption with a single encryption process using a single public key. Besides, when we execute partial decryption under a secret key of GR-NTRU, we need no information to identify each part in a whole ciphertext. Consequently, management of a public key and a corresponding set of secret keys is rather easier than the naive method. Next, we propose a concrete instantiation of our generic GR-NTRU. A multivariate polynomial ring NTRU scheme is obtained by employing a product of different cyclic groups as the basis of the group ring structure.We will show examples of those new variants of NTRU schemes with concrete parameter values, and explain how we can employ them to use the functionality of partial decryption..
360. Hiroaki Anada, Seiko Arita, Kouichi Sakurai, Attribute-based two-tier signatures
Definition and construction, 18th International Conference on Information Security and Cryptology, ICISC 2015 Information Security and Cryptology - ICISC 2015 - 18th International Conference, Revised Selected Papers, 10.1007/978-3-319-30840-1_3, 9558, 36-49, 2016.01, Attribute-based signature scheme (ABS) is a functional variant of digital signature scheme proposed in 2008 by Maji et al. The two basic requirements of ABS (and a hard task to achieve) is collusion resistance and attribute privacy. In this paper, we employ the two-tier signature (TTS) technique to achieve the collusion resistance. Here TTS was proposed in 2007 by Bellare et al., where a signer receives two tier secret keys sequentially. The secondary secret key is served as a onetime key at the timing of signing. First, we propose a definition of an attribute-based two-tier signature scheme (ABTTS). Then we provide ABTTS concretely that enjoys existential unforgeability against chosenmessage attacks, collusion resistance and attribute privacy, in the standard model. For the construction, enhancing the Camenisch-Lysyanskaya signature, we construct signature bundle schemes that are secure under the Strong RSA assumption and the Strong Diffie-Hellman assumption, respectively. These signature bundle schemes enable ABTTS to achieve attribute privacy. Then, using the signature bundle as a witness in the Σ-protocol of the boolean proof, we obtain attribute-based identification schemes (ABIDs). Finally, by applying the TTS technique to ABIDs, we achieve ABTTSs. A feature of our construction is that ABTTS in the RSA setting is pairing-free..
361. Junzuo Lai, Robert H. Deng, Changshe Ma, Kouichi Sakurai, Jian Weng, CCA-secure keyed-fully homomorphic encryption, 19th IACR International Conference on Practice and Theory in Public-Key Cryptography, PKC 2016 Public-Key Cryptography - PKC 2016 - 19th IACR International Conference on Practice and Theory in Public-Key Cryptography, Proceedings, 10.1007/978-3-662-49384-7_4, 70-98, 2016.01, To simultaneously achieve CCA security and homomorphic property for encryption, Emura et al. introduced a new cryptographic primitive named keyed-homomorphic encryption, in which homomorphic ciphertext manipulations can only be performed by someone holding a devoted evaluation key which, by itself, does not enable decryption. A keyed-homomorphic encryption scheme should provide CCA2 security when the evaluation key is unavailable to the adversary and remain CCA1-secure when the evaluation key is exposed. While existing keyedhomomorphic encryption schemes only allow simple computations on encrypted data, our goal is to construct CCA-secure keyed-fully homomorphic encryption (keyed-FHE) capable of evaluating any functions on encrypted data with an evaluation key. In this paper, we first introduce a new primitive called convertible identity-based fully homomorphic encryption (IBFHE), which is an IBFHE with an additional transformation functionality, and define its security notions. Then, we present a generic construction of CCA-secure keyed-FHE from IND-sID-CPA-secure convertible IBFHE and strongly EUF-CMA-secure signature. Finally, we propose a concrete construction of IND-sID-CPA-secure convertible IBFHE, resulting in the first CCAsecure keyed-FHE scheme in the standard model..
362. Hui Zhao, Kouichi Sakurai, Computational soundness of uniformity properties for multi-party computation based on LSSS, 7th International Conference on the Theory, Technologies and Applications of Trusted Systems, INTRUST 2015 Trusted Systems - 7th International Conference, INTRUST 2015, Revised Selected Papers, 10.1007/978-3-319-31550-8_7, 99-113, 2016.01, We provide a symbolic model for multi-party computation based on linear secret-sharing scheme, and prove that this model is computationally sound: if there is an attack in the computational world, then there is an attack in the symbolic (abstract) model. Our original contribution is that we deal with the uniformity properties, which cannot be described using a single execution trace, while considering an unbounded number of sessions of the protocols in the presence of active and adaptive adversaries..
363. Chenyutao Ke, Hiroaki Anada, Junpei Kawamoto, Kirill Morozov, Kouichi Sakurai, Cross-group secret sharing for secure cloud storage service, 10th International Conference on Ubiquitous Information Management and Communication, IMCOM 2016 ACM IMCOM 2016 Proceedings of the 10th International Conference on Ubiquitous Information Management and Communication, 10.1145/2857546.2857610, 2016.01, With the spread of the Internet, many mobile devices are used in our daily lives, such as tablets and mobile phones. Then, personal data are often saved on data servers of the storage providers such as Amazon, Google, Yahoo, Baidu and others. In this context, the secret sharing can be used to store personal data onto several providers, simultaneously reducing the risk of data loss, the data leakage to unauthorized parties, and data falsification. Secret sharing is one of the solutions to combine security and availability in the distributed storage. However, few works considered servers' affiliations, and specifically, the problem that a malicious provider may recover secret data illegally through manipulation on servers that hold enough shares to recover the secret. In this paper, to resolve the problem, we propose a two-threshold secret sharing scheme in order to enforce a new type of cross-group policy. By combining t-out-of-m providers' secret sharing scheme and a k-out-of-n servers' secret sharing scheme via an one-way function or an one-time pad, we construct a scheme that forces k shares to be collected from m groups. Compared with previous work, our scheme can attain the functionalities of proactively updating shares and adding new shares with simple computation..
364. Sabyasachi Dutta, Partha Sarathi Roy, Avishek Adhikari, Kouichi Sakurai, On the robustness of visual cryptographic schemes, 15th International Workshop on Digital-Forensics and Watermarking, IWDW 2016 Digital Forensics and Watermarking - 15th International Workshop, IWDW 2016, Revised Selected Papers, 10.1007/978-3-319-53465_719, 10082 LNCS, 251-262, 2017, In this paper, we consider the robustness of a special type of secret sharing scheme known as visual cryptographic scheme in which the secret reconstruction is done visually without any mathematical computation unlike other secret sharing schemes. Initially, secret sharing schemes were considered with the presumption that the corrupted participants involved in a protocol behave in a passive manner and submit correct shares during the reconstruction of secret. However, that may not be the case in practical situations. A minimal robust requirement, when a fraction of participants behave maliciously and submit incorrect shares, is that, the set of all shares, some possibly corrupted, can recover the correct secret. Though the concept of robustness is well studied for secret sharing schemes, it is not at all common in the field of visual cryptography. We, for the first time in the literature of visual cryptography, formally define the concept of robustness and put forward (2, n)-threshold visual cryptographic schemes that are robust against deterministic cheating. In the robust secret sharing schemes it is assumed that the number of cheaters is always less than the threshold value so that the original secret is not recovered by the coalition of cheaters only. In the current paper, We consider three different scenarios with respect to the number of cheaters controlled by a centralized adversary. We first consider the existence of only one cheater in a (2, n)-threshold VCS so that the secret image is not recovered by the cheater. Next we consider two different cases, with number of cheaters being greater than 2, with honest majority and without honest majority..
365. Yuxuan Gao, Yaokai Feng, Junpei Kawamoto, Kouichi Sakurai, A Machine Learning Based Approach for Detecting DRDoS Attacks and Its Performance Evaluation, 11th Asia Joint Conference on Information Security, AsiaJCIS 2016 Proceedings - 11th Asia Joint Conference on Information Security, AsiaJCIS 2016, 10.1109/AsiaJCIS.2016.24, 80-86, 2016.12, DRDoS (Distributed Reflection Denial of Service) attack is a kind of DoS (Denial of Service) attack, in which third-party servers are tricked into sending large amounts of data to the victims. That is, attackers use source address IP spoofing to hide their identity and cause third-parties to send data to the victims as identified by the source address field of the IP packet. This is called reflection because the servers of benign services are tricked into "reflecting" attack traffic to the victims. The most typical existing detection methods of such attacks are designed based on known attacks by protocol and are difficult to detect the unknown ones. According to our investigations, one protocol-independent detection method has been existing, which is based on the assumption that a strong linear relationship exists among the abnormal flows from the reflector to the victim. Moreover, the method is assumed that the all packets from reflectors are attack packets when attacked, which is clearly not reasonable. In this study, we found five features are effective for detecting DRDoS attacks, and we proposed a method to detect DRDoS attacks using these features and machine learning algorithms. Its detection performance is experimentally examined and the experimental result indicates that our proposal is of clearly better detection performance..
366. Longzhu Cai, Yaokai Feng, Junpei Kawamoto, Kouichi Sakurai, A behavior-based method for detecting DNS amplification attacks, 10th International Conference on Innovative Mobile and Internet Services in Ubiquitous Computing, IMIS 2016 Proceedings - 2016 10th International Conference on Innovative Mobile and Internet Services in Ubiquitous Computing, IMIS 2016, 10.1109/IMIS.2016.88, 608-613, 2016.12, DNS (Domain Name System) amplification attack has become a popular form of the attacks of the Distributed Denial of Service (DDoS) in recent years. In DNS amplification attacks, the attackers utilize spoofed source IP addresses and open recursive DNS servers to perform the bandwidth consumption attacks. A lot of responses are generated and they are sent to the targets after the attackers send only a little of DNS requests. Various methods have been proposed for detecting the DNS amplification attacks. However, almost of them have to determine parameters in advance, which is not easy for many cases. In this study, we utilized the detection pattern and combination of three features to distinguish normal and attack. It can solve the problem that limitation of detection in the case of high-frequency and low-amplification attack..
367. Pengfei Li, Yaokai Feng, Junpei Kawamoto, Kouichi Sakurai, A proposal for cyber-attack trace-back using packet marking and logging, 10th International Conference on Innovative Mobile and Internet Services in Ubiquitous Computing, IMIS 2016 Proceedings - 2016 10th International Conference on Innovative Mobile and Internet Services in Ubiquitous Computing, IMIS 2016, 10.1109/IMIS.2016.89, 603-607, 2016.12, Cyber-attack incidents have become more and more frequent and serious. As a countermeasure against cyber-attacks, the technology of (IP address etc.) trace-back to the attackers is essential. Although many methods have been proposed for this purpose, the existing techniques suffer from the following problems. Only the specific attacks can be traced back. The tracing back is too time-consuming and correct traffic-path reconfiguration cannot be guaranteed. In this study, we propose a new method to discover attackers quickly and correctly. By using simulation data, its performance is demonstrated..
368. Rohit Ahuja, Sraban Kumar Mohanty, Kouichi Sakurai, An Identity Preserving Access Control Scheme with Flexible System Privilege Revocation in Cloud Computing, 11th Asia Joint Conference on Information Security, AsiaJCIS 2016 Proceedings - 11th Asia Joint Conference on Information Security, AsiaJCIS 2016, 10.1109/AsiaJCIS.2016.23, 39-47, 2016.12, The advent of cloud computing motivates business organizations to migrate their complex data management systems from local servers to cloud servers for scalable and durable resources on pay per use basis. Considering enormous users and large amount of documents at cloud servers, there is a requirement of an access control scheme, which supports fine-grained cum flexible access control along with 'Query-Response' mechanism to enable users to efficiently retrieve desired data from cloud servers. In addition, the scheme should support considerable flexibility to revoke system privileges from user, such as to restrict user from sharing or retrieving data or both, i.e., flexible system privilege revocation and most imperatively to preserve the identity of data owner and consumer, while sharing and retrieving data. Most of the access control schemes in cloud computing till date focus on restricting user from accessing data only. In this paper, we propose an identity preserving access control scheme to simultaneously realize the notion of scalability, fine-grained cum flexible access control, efficient data utilization, identity preserving and flexible system privilege revocation. We extend Ciphertext-Policy Attribute-Set-Based Encryption (CPASBE) in a hierarchical structure of users to achieve scalability. In addition, a hybridization of proxy re-encryption and CP-ASBE is introduced to materialize the concept of flexible system privilege revocation. Furthermore, we formally prove the security of our proposed scheme based on decisional bilinear Diffie-Hellman assumption. Efficacy of our scheme is depicted by performing comprehensive experiments..
369. Ziyi Li, Junpei Kawamoto, Yaokai Feng, Kouichi Sakurai, Cyberbullying detection using parent-child relationship between comments, 18th International Conference on Information Integration and Web-Based Applications and Services, iiWAS 2016 18th International Conference on Information Integration and Web-Based Applications and Services, iiWAS 2016 - Proceedings, 10.1145/3011141.3011182, Part F126325, 325-334, 2016.11, Cyberbullying is a underlying problem in social networking service, threatening users' mental and physical health. Previous research on automated cyberbullying detection is mostly textual or social based methods. Cyberbullying content is identified through a set of textual features within the content in the former method and through social information surrounding the content in the latter method. Those methods can not cater difierent cyberbullying standard for individual SNS user since each content is evaluated using same features. Therefore, in this article we propose a automated cyberbullying detection method that utilises the parent-child relationship between comments to capture the reaction from a third party to detect cyberbullying comments. We were able to improve the effectiveness of cyberbullyingdetection using only publicly available data..
370. Takanori Suga, Takashi Nishide, Kouichi Sakurai, Character-based symmetric searchable encryption and its implementation and experiment on mobile devices, Security and Communication Networks, 10.1002/sec.876, 9, 12, 1717-1725, 2016.08, Searchable encryption allows us to perform a keyword search over encrypted data. However, we cannot efficiently perform some complex search (e.g., a wildcard search) with traditional searchable encryption schemes because they can deal with only equality matches. Our symmetric searchable encryption can deal with partial matches. This allows us to efficiently perform a wildcard search, partial match search, and so on. We also examine the feasibility of our scheme by experiments on a smartphone and tablet, and confirm our scheme can be used in these environments. Availability on portable devices will offer high convenience..
371. Yoshifumi Ueshige, Kouichi Sakurai, Analysis of "receipt-freeness" and "coercion-resistance" in biometric authentication protocols, 30th IEEE International Conference on Advanced Information Networking and Applications, AINA 2016 Proceedings - IEEE 30th International Conference on Advanced Information Networking and Applications, IEEE AINA 2016, 10.1109/AINA.2016.97, 2016-May, 769-775, 2016.05, Recently, biometric authentication protocols are developed. Security of these protocols originates in compromising no privacy information by wiretapping, malicious access and etc. in the authentication processes. With regard to this, the authors pointed out the risk of excessive collection of privacy information caused by remaining data related to biometric authentication data such as logs and intermediate processing data on the authentication servers. As a requirement against this risk, the authors introduced receipt-freeness of biometric authentication protocols. In this research, the authors develop the above research by investigating so-called coercion-resistance which means resistance against coercing user into executing biometric authentication. This paper describes definition of coercion-resistance against wiretapping coercer, relevance to receipt-freeness, and analysis of coercion-resistance in two IC card based protocols. The results show one of the protocols satisfies receipt-freeness and coercion-resistance, although another one does not satisfy..
372. Kouichi Sakurai, Amiya Nayak, Sushmita Ruj, Haojin Zhu, Arindam Pal, Message from the STPA 2016 Workshop Organizers, Proceedings - IEEE 30th International Conference on Advanced Information Networking and Applications Workshops, WAINA 2016, 10.1109/WAINA.2016.215, lxviii, 2016.05.
373. Takanori Yasuda, Kouichi Sakurai, A multivariate encryption scheme with Rainbow, Lecture Notes in Computer Science, 10.1007/978-3-319-29814-6_19, 9543, 236-251, 2016.03, Multivariate Public Key Cryptosystems (MPKC) are a candidate of post-quantum cryptography. The MPKC signature scheme Rainbow is endowed of efficient signature generation and verification, while no major attack has been reported so far. In this paper, we propose a MPKC encryption scheme based on Rainbow. The public key of Rainbow is a surjective polynomial map, whereas the encryption scheme requires an injective polynomial map. We explain how to change the public key of Rainbow to an injective map..
374. Yaokai Feng, Yoshiaki Hori, Kouichi Sakurai, A behavior-based online engine for detecting distributed cyber-attacks, 17th International Workshop on Information Security Applications, WISA 2016 Information Security Applications - 17th International Workshop, WISA 2016, Revised Selected Papers, 10.1007/978-3-319-56549-1_7, 10144 LNCS, 79-89, 2017.01, Distributed attacks have reportedly caused the most serious losses in recent years. Here, distributed attacks means those attacks conducted collaboratively by multiple hosts. How to detect distributed attacks has become one of the most important topics in the cyber security community. Many detection methods have been proposed, each of which, however, has its own weak points. For example, detection performance of information theory based methods strongly depends on the information theoretic measures and signature-based methods suffer from the fact that they can deal with neither new kinds of attacks nor new variants of existing attacks. Recently, behavior-based method has been attracting great attentions from many researchers and developers and it is thought as the most promising one. In behavior-based approaches, normal behavior modes are learned/extracted from past traffic data of the monitored network and are used to recognize anomalies in the future detection. In this paper, we explain how to implement an online behavior-based engine for detecting distributed cyber-attacks. Detection cases of our engine are also introduced and some actual attacks/incidents have been captured by our detection engine..
375. Yaokai Feng, Yoshiaki Hori, Kouichi Sakurai, A detection system for distributed DoS attacks based on automatic extraction of normal mode and its performance evaluation, 10th International Conference on Security, Privacy and Anonymity in Computation, Communication and Storage, SpaCCS 2017 Security, Privacy, and Anonymity in Computation, Communication, and Storage - 10th International Conference, SpaCCS 2017, Proceedings, 10.1007/978-3-319-72389-1_37, 461-473, 2017.01, Distributed DoS (Denial-of-Service) attacks, or say DDoS attacks, have reportedly caused the most serious losses in recent years and such attacks are getting worse. How to efficiently detect DDoS attacks has naturally become one of the hottest topics in the cyber security community and many approaches have been proposed. The existing detection technologies, however, have their own weak points. For example, methods based on information theory must choose an information theoretic measures carefully which play an essential role on the detection performance and such methods are efficient only when there are a significantly large number of anomalies present in the data; signature-based methods can not deal with new kinds of attacks and new variants of existing attacks, and so on. The behavior-based ones have been thought to be promising. However, they often need some parameters to define the normal nodes and such parameters cannot be determined easily in advance in many actual situations. In our previous work, an algorithm without parameters was proposed for extracting normal nodes from the historic traffic data. In this paper, we will explain a practical off-line detection system for DDoS attacks that we developed based on that algorithm in a project called PRACTICE (Proactive Response Against Cyber-attacks Through International Collaborative Exchange). The general flow of our detection system and the main specific technologies are explained in details and its detection performance is also verified by several actual examples..
376. Tomohisa Ishikawa, Kouichi Sakurai, A proposal of Event Study Methodology with Twitter Sentimental Analysis for risk management, 11th International Conference on Ubiquitous Information Management and Communication, IMCOM 2017 Proceedings of the 11th International Conference on Ubiquitous Information Management and Communication, IMCOM 2017, 10.1145/3022227.3022240, 2017.01, Once organizations have the security incident and breaches, they have to pay tremendous costs. Although visible cost, such as the incident response cost, customer follow-up care, and legal cost are predictable and calculable, it is tough to evaluate and estimate the invisible damage, such as losing customer loyalty, reputation impact, and the damage of branding. This paper proposes a new method, called "Event Study Methodology with Twitter Sentimental Analysis" to evaluate the invisible cost. This method helps to assess the impact of the security breach and the impact on corporate valuation..
377. Rohit Ahuja, Sraban Kumar Mohanty, Kouichi Sakurai, A scalable attribute-set-based access control with both sharing and full-fledged delegation of access privileges in cloud computing, Computers and Electrical Engineering, 10.1016/j.compeleceng.2016.11.028, 57, 241-256, 2017.01, The benefits of cloud computing motivate enterprises to migrate their IT infrastructure on cloud servers. Enterprise needs to entrust untrusted cloud service provider, which gives rise to various security and privacy concerns. To address these concerns, numerous schemes in cloud computing employed attribute-based encryption schemes. However, existing schemes are neither flexible enough to provide users complete liberty on delegation of their access privileges nor grant shared access privileges among users of a group to jointly address a responsibility. This paper introduces hierarchical attribute-set-based access control scheme by employing ciphertext-policy attribute-set-based encryption with a hierarchical structure of users to achieve scalability. The proposed scheme simultaneously achieves the notion of fine-grained cum flexible access control, privacy preserving, efficient data utilization and imperatively provides users full-fledged liberty on delegation of their access privileges. Furthermore, we formally prove that proposed scheme is secure under decisional bilinear Diffie–Hellman assumption..
378. Liang Lu, Yaokai Feng, Kouichi Sakurai, C&C session detection using random forest, 11th International Conference on Ubiquitous Information Management and Communication, IMCOM 2017 Proceedings of the 11th International Conference on Ubiquitous Information Management and Communication, IMCOM 2017, 10.1145/3022227.3022260, 2017.01, DDoS (Distributed Denial of Service) attack is one of the most used DoS (Denial of Service) attack. It is a distributed attack in which an attacker uses a multitude of compromised computers to attack a single target. Those compromised computers that actually execute the attack are called botnet. To hide their identity, the attacker usually uses a third-party server to control and send attack command to bots, this kind of server is called C&C (command & control) server. The detection of C&C sessions is a strong proof of botnet detection and early detection of DDoS attacks as C&C connections occur before a DDoS attack. Network traffic analysis is an effective method to detect C&C sessions as it is hard to avoid encrypting the payload or change command code. We consider a new feature vector with 55 features, and use a random forest algorithm to build the classifier. Random forest is an ensemble of classifiers that can deal with high-dimension problems. In fact, it can also calculate the importance of features that will help us find the key features responsible for the detection of C&C sessions. Experimental results show that our approach has better performance on C&C session detection..
379. Jiawei Su, Danilo Vasconcellos Vargas, Kouichi Sakurai, Evasion attacks against statistical code obfuscation detectors, 12th International Workshop on Security, IWSEC 2017 Advances in Information and Computer Security - 12th International Workshop on Security, IWSEC 2017, Proceedings, 10.1007/978-3-319-64200-0_8, 10418 LNCS, 121-137, 2017.01, In the domain of information security, code obfuscation is a feature often employed for malicious purposes. For example there have been quite a few papers reporting that obfuscated JavaScript frequently comes with malicious functionality such as redirecting to external malicious websites. In order to capture such obfuscation, a class of detectors based on statistical features of code, mostly n-grams have been proposed and been claimed to achieve high detection accuracy. In this paper, we formalize a common scenario between defenders who maintain the statistical obfuscation detectors and adversaries who want to evade the detection. Accordingly, we create two kinds of evasion attack methods and evaluate the robustness of statistical detectors under such attacks. Experimental results show that statistical obfuscation detectors can be easily fooled by a sophisticated adversary even in worst case scenarios..
380. Taku Nishigori, Junpei Kawamoto, Kouichi Sakurai, Improving the accuracy of signature authentication using the eight principles of yong, 11th International Conference on Ubiquitous Information Management and Communication, IMCOM 2017 Proceedings of the 11th International Conference on Ubiquitous Information Management and Communication, IMCOM 2017, 10.1145/3022227.3022258, 2017.01, The signature authentication on smartphones has been studied as a method to protect personal information. Its authentication accuracy is a challenge due to restrictions such as size of the terminal. In this paper, a signature authentication method that incorporates the calligraphy concept called Eight Principles of Yong is proposed for users of Chinese characters. The Eight Principles of Yong means that the character Yong has the eight techniques needed to describe any Chinese character. In the method, the certifier makes clusters from Yong in advance. Strokes of the template are allocated in clusters. At the time of authentication, strokes of the character are allocated in these clusters. If the cluster is the same as the stroke, the distance between the data decreases..
381. Kirill Morozov, Partha Sarathi Roy, Kouichi Sakurai, On unconditionally binding code-based commitment schemes, 11th International Conference on Ubiquitous Information Management and Communication, IMCOM 2017 Proceedings of the 11th International Conference on Ubiquitous Information Management and Communication, IMCOM 2017, 10.1145/3022227.3022327, 2017.01, In this work, we construct a dual version of statistically binding commitment scheme by Jain et al. (Asiacrypt 2012) with shorter commitment size under hardness of syndrome decoding. Then, we point out that perfectly binding variants of the above schemes follow directly from the Randomized McEliece and Niederreiter public key encryption schemes, assuming indistinguishability of permuted Goppa codes, as well as hardness of the exact learning parity with noise (xLPN) problem (for the McEliece scheme) and hardness of syndrome decoding (for the Niederreiter scheme). Our key observation here is that perfect binding (as opposed to statistical binding) requires exact knowledge of minimal distance of the underlying code. Finally, we provide security evaluation of our proposals, and compare their performance with that of existing schemes..
382. Tomohisa Ishikawa, Kouichi Sakurai, Parameter manipulation attack prevention and detection by using web application deception proxy, 11th International Conference on Ubiquitous Information Management and Communication, IMCOM 2017 Proceedings of the 11th International Conference on Ubiquitous Information Management and Communication, IMCOM 2017, 10.1145/3022227.3022300, 2017.01, The attack abusing web application vulnerabilities are currently classified into traditional attack threats. However, security breaches by web application attacks are still reported via mass media. Although the vulnerabilities in popular products such as Microsoft IIS or Apache are quickly discovered by security researchers around the world, it is hard to identify the vulnerabilities in customized web applications developed by each organization. On top of that, in the case of large corporations, it is hard to manage all web applications since their business domains are diversified, and each division has various web applications. In this paper, we propose web application deception proxy as a defense approach, and we show that it is very helpful to prevent and detect web application attacks..
383. Linghuan Xiao, Shinichi Matsumoto, Tomohisa Ishikawa, Kouichi Sakurai, SQL injection attack detection method using expectation criterion, 4th International Symposium on Computing and Networking, CANDAR 2016 Proceedings - 2016 4th International Symposium on Computing and Networking, CANDAR 2016, 10.1109/CANDAR.2016.74, 649-654, 2017.01, SQL Injection attack is a kind of attack to a web application that accesses the database of the web application illegitimate. Along with the increasing use of web applications, the database where stores much sensitive information became more and more valuable and vulnerable. Eventually, SQL Injection attack has become rank one in top ten vulnerabilities as specified by Open Web Application Security Project (OWASP). In the other hand, although there was proposed a lot of methods to address the SQL injection attack, the current approaches almost have the limitation to detect full scope of the attack. What is more, the approaches have high precision in detecting pre-existing attacks though, but cannot detect unknown attacks. In this paper, we present an expectation-based solution to address SQL injection attack. Our proposal mainly has two phases. In the first phase, we calculate the occurrence probability of the SQL injection attack special characters in attack dataset and typical dataset respectively, and in the second phase we detect SQL injection attack base on expectation calculating take advantage of the computed occurrence probability..
384. Mosarrat Jahan, Mohsen Rezvani, Qianrui Zhao, Partha Sarathi Roy, Kouichi Sakurai, Aruna Seneviratne, Sanjay Jha, Light Weight Write Mechanism for Cloud Data, IEEE Transactions on Parallel and Distributed Systems, 10.1109/TPDS.2017.2782253, 29, 5, 1131-1146, 2018.05, Outsourcing data to the cloud for computation and storage has been on the rise in recent years. In this paper we investigate the problem of supporting write operation on the outsourced data for clients using mobile devices. We consider the Ciphertext-Policy Attribute-based Encryption (CP-ABE) scheme as it is well suited to support access control in outsourced cloud environments. One shortcoming of CP-ABE is that users can modify the access policy specified by the data owner if write operations are incorporated in the scheme. We propose a protocol for collaborative processing of outsourced data that enables the authorized users to perform write operation without being able to alter the access policy specified by the data owner. Our scheme is accompanied with a light weight signature scheme and simple, inexpensive user revocation mechanism to make it suitable for processing on resource-constrained mobile devices. The implementation and detailed performance analysis of the scheme indicate the suitability of the proposed scheme for real mobile applications. Moreover, the security analysis demonstrates that the security properties of the system are not compromised..
385. Debdas Ghosh, Debasis Giri, R. N. Mohapatra, Ekrem Savas, Kouichi Sakurai, L. P. Singh, Preface, 4th International Conference on Mathematics and Computing, ICMC 2018 Communications in Computer and Information Science, 834, IX-X, 2018.01.
386. Pinaki Sarkar, Morshed Uddin Chowdhury, Kouichi Sakurai, Secure combinatorial key predistribution scheme for sensor networks by regulating frequencies
magneto optic sensors, Concurrency Computation Practice and Experience, 10.1002/cpe.4017, 29, 23, 2017.12, Low cost, decentralized architecture and ad hoc nature are a few desirable properties of wireless sensor networks that make them well suited for gathering sensitive information in hazardous deployment grounds. Existing security protocols exploit various cryptographic tools to strengthen their security. Not many works focus on constraints faced by an adversary. One such constraint being practical difficulties to trace a particular frequency band from a large range of unknown frequencies, specially in unharmonious geographical locations. Our research capitalizes on this weakness encountered by an adversary and preassigns nodes with multiple frequency bands from a wide range of frequencies allocated to the network. Deployed nodes can discover these bands during set network setup phase by a simple trick. Nodes are to internally switch their frequency bands depending on parametric variation that are caused by an (external) impulse. Experiments conducted using magneto optic sensors confirm that any variation of their parameter affects frequencies of emergent waves. Similar behavior is expected from application specific sensors. Frequency regulation (FR) concept is applied to combinatorial key predistribution schemes (KPS) having (regular) degree r. Depending on r and each node's capability to switch internal frequencies, nodes are preallocated with n frequency bands. This naturally partitions the (distributed) network and results in improved resilience. Combining our FR concept to a KPS where the number of shared key between a pair of nodes is at most one (γ ≤ 1) may yield best case scenario of an ideally resilient key predistribution. Our analysis of systems that combines FR idea with KPS where γ > 1 leads to an optimized key-band distribution argument and drastic resilience improvements. Results of simulations conducted assuming real-life scenario ascertain our analysis and establishes superior performance of our protocols as compared to prominent ones..
387. Hiroaki Anada, Junpei Kawamoto, Chenyutao Ke, Kirill Morozov, Kouichi Sakurai, Cross-group secret sharing scheme for secure usage of cloud storage over different providers and regions, Journal of Supercomputing, 10.1007/s11227-017-2009-7, 73, 10, 4275-4301, 2017.10, With the spread of the Internet, more and more data are being stored in the cloud. Here the technique of secret sharing can be naturally applied in order to provide both security and availability of the stored data, hereby reducing the risks of data leakage and data loss. The privacy property of secret sharing ensures protection against unauthorized access, while protection against data loss may be attained by distributing shares to the servers located in different regions. However, there is still a problem: If we naively employ the secret sharing technique without regarding to whom the cloud servers belong, a dishonest provider can obtain the secret data by collecting enough shares from its servers. In this scenario, there is a need to distribute shares over cloud services operated by different providers. In this paper, we propose a simple secret sharing technique, a cross-group secret sharing (CGSS), which is suitable for storing the data on cloud storage distributed over different groups—that is, different providers and regions. By combining an ℓ-out-of-m threshold secret sharing scheme with a k-out-of-n threshold secret sharing scheme using a symmetric-key encryption scheme, we construct the CGSS scheme that forces k shares to be collected from ℓ groups. Compared with the previous works, our scheme attains the functionality with reasonable computation. We also formalize the problem of allocating shares over different providers and regions as an optimization problem and show the design principles, which one must follow, when applying our proposal in practical settings. An experiment on real IaaS systems shows effectiveness of our proposed scheme, CGSS..
388. Mosarrat Jahan, Partha Sarathi Roy, Kouichi Sakurai, Aruna Seneviratne, Sanjay Jha, Secure and light weight fine-grained access mechanism for outsourced data, 16th IEEE International Conference on Trust, Security and Privacy in Computing and Communications, 11th IEEE International Conference on Big Data Science and Engineering and 14th IEEE International Conference on Embedded Software and Systems, Trustcom/BigDataSE/ICESS 2017 Proceedings - 16th IEEE International Conference on Trust, Security and Privacy in Computing and Communications, 11th IEEE International Conference on Big Data Science and Engineering and 14th IEEE International Conference on Embedded Software and Systems, Trustcom/BigDataSE/ICESS 2017, 10.1109/Trustcom/BigDataSE/ICESS.2017.238, 201-209, 2017.09, In this paper we explore the problem of providing selective read/write access to the outsourced data for clients using mobile devices in an environment that supports users from multiple domains and where attributes are generated by multiple authorities. We consider Ciphertext-Policy Attribute-based Encryption (CP-ABE) scheme as it can provide access control on the encrypted outsourced data. One limitation of CP-ABE is that users can modify the access policy specified by the data owner if write operations are introduced in the scheme. We propose a protocol for providing different levels of access to outsourced data that permits the authorized users to perform write operation without altering the access policy specified by the data owner. Our scheme provides fine-grained read/write access to the users, accompanied with a light weight signature scheme and computationally inexpensive user revocation mechanism suitable for resource-constrained mobile devices. The security analysis demonstrates the robustness of the proposed scheme..
389. Samiran Bag, Sushmita Ruj, Kouichi Sakurai, Bitcoin Block Withholding Attack
Analysis and Mitigation, IEEE Transactions on Information Forensics and Security, 10.1109/TIFS.2016.2623588, 12, 8, 1967-1978, 2017.08, We address two problems: First, we study a variant of block withholding (BWH) attack in Bitcoins and second, we propose solutions to prevent all existing types of BWH attacks in Bitcoins. We analyze the strategies of a selfish Bitcoin miner who in connivance with one pool attacks another pool and receives reward from the former mining pool for attacking the latter. We name this attack as 'sponsored block withholding attack.' We present detailed quantitative analysis of the monetary incentive that a selfish miner can earn by adopting this strategy under different scenarios. We prove that under certain conditions, the attacker can maximize her revenue by adopting some strategies and by utilizing her computing power wisely. We also show that an attacker may use this strategy for attacking both the pools for earning higher amount of incentives. More importantly, we present a strategy that can effectively counter block withholding attack in any mining pool. First, we propose a generic scheme that uses cryptographic commitment schemes to counter BWH attack. Then, we suggest an alternative implementation of the same scheme using hash function. Our scheme protects a pool from rogue miners as well as rogue pool administrators. The scheme and its variant defend against BWH attack by making it impossible for the miners to distinguish between a partial proof of work and a complete proof of work. The scheme is so designed that the administrator cannot cheat on the entire pool. The scheme can be implemented by making minor changes to existing Bitcoin protocol. We also analyze the security of the scheme..
390. Satya Lokam, Sushmita Ruj, Kouichi Sakurai, BCC'17 chairs' Welcome, BCC 2017 - Proceedings of the ACM Workshop on Blockchain, Cryptocurrencies and Contracts, co-located with ASIA CCS 2017, iii, 2017.04.
391. Mojtaba Alizadeh, Mohammad Hessam Tadayon, Kouichi Sakurai, Sabariah Baharun, Hiroaki Anada, Mazdak Zamani, Akram Zeki, Shehzad Ashraf Chaudhry, Muhammad Khurram Khan, Comments and improvements of 'HOTA
Handover optimized ticket-based authentication in network-based mobility management', 20th Conference on Innovations in Clouds, Internet and Networks, ICIN 2017 Proceedings of the 2017 20th Conference on Innovations in Clouds, Internet and Networks, ICIN 2017, 10.1109/ICIN.2017.7899399, 112-116, 2017.04, Nowadays, various mobile devices are being an inseparable part of our normal life. Mobile users tend to be connected to the Internet seamlessly, which is provided by mobility management protocols. One of the latest mobility management protocol is Proxy Mobile IPv6 (PMIPv6), which is a network-based protocol. Authentication mechanism as a critical security procedure is not specified in PMIPv6, hence various authentication methods have been proposed. Lee and Bonin proposed a ticket-based authentication scheme for PMIPv6, which is called HOTA in 2013. Even though, HOTA offers some security protection mechanisms, but is vulnerable to DoS attack. Furthermore, we show other existing drawbacks to the scheme such as vulnerability against de-synchronization attack and Session Hijacking attack. In this paper, we propose an enhancement method to mitigate these security drawbacks. Finally, security and performance of the proposed method are analyzed and compared to HOTA method..
392. Ryosuke Miyazaki, Junpei Kawamoto, Shinichi Matsumoto, Kouichi Sakurai, Host independent and distributed detection system of the network attack by using OpenFlow, 31st International Conference on Information Networking, ICOIN 2017 31st International Conference on Information Networking, ICOIN 2017, 10.1109/ICOIN.2017.7899511, 236-241, 2017.04, Recently, there are many types of cyber attacks and we should detect as many types as possible. In order to detect a wide variety of attacks, a complete distributed multi-Agent system is proposed. However, it requires the software installation in all hosts. The lack of resources also makes it hard to introduce the system to the devices. In this paper, we design a distributed defense algorithm employing a multi-Agent system. However, it is hard to detect the wide and shallow attacks such as horizontal portscan and if the systems is completely distributed. Therefore, we need to watch for the whole network in order to detect such attacks. Here, it is proposed to combine the system with OpenFlow which is suitable for having an overall network view. In general, however, OpenFlow has a central control system which is not scalable. Thus, we also propose to use several OpenFlow controllers and share information among them. By sharing information, we show that it is possible to detect a horizontal portscan..
393. Rohit Ahuja, Sraban Kumar Mohanty, Kouichi Sakurai, A traceable signcryption scheme for secure sharing of data in cloud storage, 16th IEEE International Conference on Computer and Information Technology, CIT 2016 Proceedings - 2016 16th IEEE International Conference on Computer and Information Technology, CIT 2016, 2016 6th International Symposium on Cloud and Service Computing, IEEE SC2 2016 and 2016 International Symposium on Security and Privacy in Social Networks and Big Data, SocialSec 2016, 10.1109/CIT.2016.52, 524-531, 2017.03, Nowadays cloud servers become the primary choice to store and share data with multiple recipients. The storage of personal information on cloud servers may result in the exposure of confidential information to unauthorized individuals or organizations. Several solutions employing attribute-based encryption schemes have been proposed for secure sharing of data using cloud servers. However, most of the solutions fail to trace the traitors, who intentionally leaked their data access privileges for personal gain. This paper introduces a traceable ciphertext policy attribute-based signcryption (sign-then-encrypt) scheme to simultaneously realize the notion of traitor-tracing, fine-grained access control, sender anonymity, message integrity, authenticity and sensitivity by extending traceable attribute based encryption scheme using attribute-based signature. Single authority may compromise user's key. Hence to reduce the trust on authority, our proposed scheme employs different authorities for key generation and traitor-tracing. In addition, our proposed scheme preserves message sensitivity by allowing the data-owner to define message category label. We analyze the performance of our scheme with respect to secret key size, ciphertext size, computation cost involves in signcryption and designcryption and compare it with existing schemes to show its efficacy..
394. Tomohisa ISHIKAWA, Kouichi Sakurai, A proposal of event study methodology with Twitter sentimental analysis for risk management., Proceedings of the 11th International Conference on Ubiquitous Information Management and Communication, IMCOM 2017, Beppu, Japan, January 5-7, 2017. ACM 2017, , 2017.01, [URL].
395. Ryosuke MIYAZAKI, Junpei Kawamoto, Shinichi MATSUMOTO, Kouichi Sakurai, Host independent and distributed detection system of the network attack by using OpenFlow. ICOIN 2017: 236-241, 2017 International Conference on Information Networking (ICOIN), DOI: 10.1109/ICOIN.2017.7899511, 2017.06, [URL].
396. Takanori SSUGA, Takashi NISHIDE, Kouichi Sakurai, Character-based symmetric searchable encryption and its implementation and experiment on mobile devices. , Security and Communication Networks , DOI: 10.1002/sec.876, 9, (12), 1717-1725, 2016.08, [URL].
397. Mojtaba Alizadeh, Saeid Abolfazli, Mazdak Zamani, Sabariah Baharun, Kouichi Sakurai,
Authentication in mobile cloud computing: A survey. 59-80, Journal of Network and Computer Applications, https://doi.org/10.1016/j.jnca.2015.10.005, 59-80, 2016.02, [URL].
398. Chunlu Chen, Hiroaki ANADA, Junpei Kawamoto, Kouichi Sakurai, A Hybrid Encryption Scheme with Key-cloning Protection: User / Terminal Double Authentication via Attributes and Fingerprints, Journal of Internet Services and Information Security, Volume 6, 2016.05, Internet service has enabled digital contents to be shared faster and easier, but on the other side it raised an issue of illegal copy of the digital contents. Public key encryption schemes solve this issue partially. However, there is still a weak point that the secret key is not completely protected; that is, public key encryption schemes suffer from illegal copy of secret keys (the key-cloning problem). In this paper, first, we discuss the usability of terminal fingerprints for key-cloning protection. Next, we propose a hybrid encryption scheme using terminal fingerprints to protect the secret keys from the key-cloning. Based on an assumption that the terminal fingerprint is unchangeable and unextractable even by the user of the terminal, our hybrid encryption scheme can be effectively used as a method of the key-cloning protection. Then, we instantiate our hybrid encryption scheme as a combination of the attribute-based encryption scheme and the RSA encryption scheme; the attribute-based encryp- tion scheme functions as a mechanism for authentication of user’s attributes, and the RSA encryption scheme functions as a mechanism for authentication of a terminal device. Terminal fingerprint that is a feature of the device is used to generate a secret key of the RSA encryption..
399. Chenyutao Ke, Hiroaki Anada, Junpei Kawamoto, Kirill MOROZOV, Kouichi Sakurai, Cross-group Secret Sharing for Secure Cloud Storage Service , ACM IMCOM '16, January 04-06, 2016, Danang, Viet Nam , DOI: http://dx.doi.org/10.1145/2857546.2857610 , 2016.01.
400. Sushimita Ruj, Kouichi Sakurai, Secure and Privacy Preserving Hierarchical Wireless Sensor Networks using Hybrid Key Management Technique, 2013 IEEE GLOBAL COMMUNICATIONS CONFERENCE (GLOBECOM), 10.1109/GLOCOM.2013.6831104, 402-407, 2013.12.
401. Yuto Nakano, Kazuhide Fukushima, Shinsaku Kiyomoto, Tsukasa Ishiguro, Yutaka Miyake,, Toshiaki Tanaka, Kouichi Sakurai, Fast Implementation of KCipher-2 for Software and Hardware, IEICE Trans., 97, D(1), 43-52, 2014.01.
402. Angsuman Das, Avisheck Adhikari, Kouichi Sakurai, PLAINTEXT CHECKABLE ENCRYPTION WITH DESIGNATED CHECKER, ADVANCES IN MATHEMATICS OF COMMUNICATIONS, 10.3934/amc.2015.9.37, 9, 1, 37-53, 2015.02.
403. Chunhua Su, Jianying Zho, Feng Bao, Tsuyoshi Takagi, Kouichi Sakurai, Collaborative agglomerative document clustering with limited information disclosure
, Security and Communication Networks , 7, 6, 964-978, 2014.06.
404. Rimba Whidiana Ciptasari, Kyung Hyune Rhee, Kouichi Sakurai, An enhanced audio ownership protection scheme based on visual cryptography., EURASIP J. Information Security , 2014.02.
405. Zhongqqiang Zhang, Hiroaki Aanada, Junpei Kawamoto, Kouichi Sakurai, Detection of Illegal Players in Massively Multiplayer Online Role Playing Game by Classification Algorithms., AINA, IEEE Computer Society, 2015.03.
406. Kuo-Yang Wu, Kuo-Yu Tsai, Tzong-Chen Wu, Kouichi Sakurai, Provably Secure Anonymous Authentication Scheme for Roaming Service in Global Mobility Networks, J. Inf. Sci. Eng., 31, 2, 727-742 , 2015.03.
407. Satoshi TANAKA, Chen-Mou CHENG, Takanori YASUDA, Kouichi Sakurai, Parallelization of QUAD Stream Cipher Using Linear Recurring Sequences on Graphics Processing Units. , CANDAR 2014: 543-548, 2014.12.
408. Yasufumi Hashimoto, Tsuyoshi Takagi, Kouichi Sakurai, General Fault Attacks on Multivariate Public Key Cryptosystems, IEICE Transactions, Volume 96-A, 2013.01.
409. Yizhi Ren, Mingchu Li, Yang Xiang, Yongrui Cui, Kouichi Sakurai, Evolution of cooperation in reputation system by group-based scheme, The Journal of Supercomputing, Volume 63, 2013.01.
410. Jingyu Hua, Kouichi Sakurai, Botnet command and control based on Short Message Service and human mobility, Computer Networks [and ISDN Systems], Volume 57, 2013.02.
411. Satoshi Tanaka, Takashi Nishide, Kouichi Sakurai, Efficient implementation for QUAD stream cipher with GPUs, Computer Science and Information Systems, Volume 10, 2013.02.
412. Nobuyuki Teraura, Kouichi Sakurai, Confidentiality of 2D Code using Infrared with Cell-level Error Correction, International Journal of Interactive Multimedia and Artificial Intelligence, Volume 2, 2013.03.
413. Yaokai Feng, Yoshiaki Hori, Jun'ichi Takeuchi, Kouichi Sakurai, A Behavior-based Method for Detecting Distributed Scan Attacks in Darknets, Journal of Information Processing, Volume 21, 2013.07.
414. Rimba Whidiana Ciptasari, Kyung Hyune Rhee, Kouichi Sakurai, Exploiting reference images for image splicing verification, Digital Investigation, Volume 10, 2013.10.
415. Laiping Zhao, Yizhi Ren, Kouichi Sakurai, Reliable workflow scheduling with less resource redundancy, Parallel Computing, Volume 39(10), 2013.10.
416. Amril Syalim, Takashi Nishide, Kouichi Sakurai, Supporting Secure Provenance Update by Keeping "Provenance" of the Provenance, ICT-EurAsia 2013, 2013.03.
417. Yizhi Ren, MingChu Li, Kouichi Sakurai, FineTrust: a fine-grained trust model for peer-to-peer networks, Security and Communication Networks 4(1): 61-69 (2011), Vol.4, No.1, pp.61-69, 2011.01.
418. Yizhi Ren, MingChu Li, Kouichi Sakurai, FineTrust: a fine-grained trust model for peer-to-peer networks, Security and Communication Networks 4(1): 61-69 (2011), Vol.4, No.1, pp.61-69, 2011.01.
419. SU Chunhua, BAO Feng, ZHOU Jianying, TAKAGI Tsuyoshi, SAKURAI Kouich, Distributed Noise Generation for Density Estimation Based Clustering without Trusted Third Party, IEICE Transactions on Fundamentals of Electronics, Communications and Computer Sciences, 2009.08.
420. YOU Ilsun, SAKURAI Kouichi, HORI Yoshiaki, An Enhanced Security Protocol for Fast Mobile IPv6, IEICE Transactions on Information and Systems, 2009.10.
421. YOU Ilsun, SAKURAI Kouichi, HORI Yoshiaki, A Security Analysis on Kempf-Koodlis Security Scheme for Fast Mobile IPv6, IEICE Transactions on Communications, 2009.06.
422. SU Chunhua, BAO Feng, ZHOU Jianying, TAKAGI Tsuyoshi, SAKURAI Kouichi, Security and Correctness Analysis on Privacy-Preserving k-Means Clustering Schemes, IEICE Transactions on Fundamentals of Electronics, Communications and Computer Sciences, 2009.05.
423. Yongrui CUI, Mingchu LI, Yizhi REN, Kouichi SAKURAI, An Adaptive Reputation-Based Algorithm for Grid Virtual Organization Formation, IEICE Transactions on Fundamentals of Electronics, Communications and Computer Sciences, 2009.05.
424. Y.Sakai, K. SAKURAI and M. Ishizuka, Secure hyperelliptic cryptosystems and their performance, Proc. PKC'98, pp.164-181, 1998.01.
425. M.David and K. SAKURAI, Security Issues for Contactless Smart Cards, Proc. PKC'98, pp.247-352, 1998.01.
426. G. Di Crecenzo, K. SAKURAI and M. Yung, Result-indistinguishable zero-knowledge proofs: increased power and constant-round protocols, STACS 98, 15th Annual Symposium on Theoretical Aspects of Computer Science, 1373, 511-521, pp.511-521, 1998.01.
427. S.Miyazaki, and K. SAKURAI, A more efficient untraceable e-cash system with partially blind signatures based on the the discrete logarithm problem, Proc.Financial Cryptology'98, pp.296-308, 1998.01.
428. Y.Sakai, K. SAKURAI and M. Ishizuka, Secure hyperelliptic cryptosystems and their performance, Proc. Public Key Cryptography'98, pp.164-181, 1998.01.
429. G. Di Crecenzo, K. SAKURAI and M. Yung, Checking programs discreteetly: Demonstrating result-correctness efficiently while concealing it, Algorithms and Computation 9th International Symposium, ISAAC'98, 1533, 59-68, pp. 59-68, 1998.01.
430. Y.Sakai, K. SAKURAI, Design of Hyperelliptic Cryptosystems in Small Characteristic and a Software Implementation over $F_{2^n}$, Proc. of ASIACRYPT'98, 1514, 80-94, 1998.01.
431. S.Miyazaki, I. Kuroda, and K. SAKURAI, Toward Fair International Key Escrow -- An attempt by distributed Trusted Third Agencies with threshold cryptography --, Proc. 1999 International Workshop on Practice and Theory in Public Key Cryptography, 1560, 171-187, pp.171-187, 1999.01.
432. M.Shingo and K. SAKURAI, Classification of Chaum-Fiat-Naor Paradigm based anonymous electronic cash systems accroding to vulunerability aganist insider-attacks from untrusted authorities, Proc. International Workshop on Cryptographic Techniques & E-Commerce, pp.262-271, 1999.01.
433. K. SAKURAI and S.Miyazaki, A Bulletin-Board Based Digital Auction Scheme with Bidding Down Strategy - Towards Anonymous Electronic Bidding without Anonymous Channels nor Trusted Centers, Proc. International Workshop on Cryptographic Techniques & E-Commerce, pp.180-187, 1999.01.
434. S.Miyazaki, and K. SAKURAI, A Parallel Withstanding Attack with Forging Key Certificates on an Electronic Cash System Based on Message-Recovery Blind Digital Signatures, Proc. International Workshop on Cryptographic Techniques & E-Commerce, pp.163-169, 1999.01.
435. Tetsuya Tamura, Kouichi SAKURAI, A Hardware-Oriented Algorithm for Computing in Jacobians and Its Implementation for Hyperelliptic Cryptosystems, PreProc. 1999 International Conference on Information Security and Cryptology, 1787, 221-235, 1999.12.
436. Shingo MIYAZAKI, Kouichi SAKURAI and Moti YUNG, On Threshold RSA-Signing with no Dealer, PreProc. 1999 International Conference on Information Security and Cryptology, 1787, 197-207, 1999.12.
437. Yasuyuki Sakai and Kouichi SAKURAI, Over $F_p$ vs. $F_{2^n}$ over and on Pentium vs. on Alpha in Software Implementation of Hyperelliptic Curve, PreProc. 1999 International Conference on Information Security and Cryptology, 1787, 82-101, 1999.12.
438. I. Duursma, and K. SAKURAI, Efficient algorithms for the Jacobian variety fo hyperelliptic curves $y^2 = x^p -x + 1$ over a finite field of odd characteristic $p$, Coding Theory, Cryptography and related areas, 1999.01.
439. Katsuyuki Okeya, Hiroyuki Kurumatani, Kouichi Sakurai, Elliptic Curves with the Montgomery-Form and Their Cryptographic Applications, Public Key Cryptography (PKC 2000), 1751, 238-257, pp.238-257, 2000.01.
440. G. Di Crecenzo, K. SAKURAI and M. Yung, On zero-knowledge proofs: "from membership to decision", Proc. ACM STOC2000, 2000.05.
441. Toru Inoue and Kouichi SAKURAI, Making Hash Functions from Block Ciphers secure and efficient by using convolutional codes, Proc. PKC2000, 1751, 391-404, pp.391-404, 2000.01.
442. Kouichi SAKURAI, Shingo Miyazaki, An Anonymous Electronic Bidding Protocol Based on New Convertible Group Signature Scheme, Proc. ACISP2000, 2000.07.
443. Yasuyuki Sakai, Kouichi SAKURAI, Efficient Scalar Multiplication on Elliptic Curves without Repeated Doublings and their Practical Performance, Proc. ACISP2000, 2000.07.
444. Katsuyuki Okeya, Kouichi Sakurai, Power Analysis Breaks Elliptic Curve Cryptosystems even Secure against the Timing Attack, Progress in Cryptology - INDOCRYPT 2000, pp.178-190, 2000.01.
445. K.Okeya and K.SAKURAI, Efficient elliptic curve cryptosystems from a scalar multiplication algorithm with recovery of the y-coordinate on a Montgomery-form elliptic curve, Proc. Workshop on Cryptographic Hardware and Embedded Systems 2001, pp.126-141, 2001.05.
446. Y.Sakai and K.SAKURAI, On the Power of Direct Computations in Speeding Up Elliptic Scalar Multiplication, PreProc. Eighth Annual Workshop on Selected Areas in Cryptography (Aug. 2001), 2001.08.
447. Hirakiuchi DAISUKE , Kouichi Sakurai, English vs. Sealed bid in anonymous electronic auction protocols, Proc. of 10th IEEE international workshops on enabling technologies, WETICE 2001, 10.1109/ENABL.2001.953409, 171-176, pp.171-176, 2001.01.
448. Katsuyuki Okeya, Kouichi Sakurai, Efficient Elliptic Curve Cryptosystems from a Scalar Multiplication Algorithm with Recovery of the $y$-Coordinate on a Montgomery-Form Elliptic Curve, Cryptographic Hardware and Embedded System (CHES 2001), pp.126-141, 2001.01.
449. Katsuyuki Okeya, Kunihiko Miyazaki, Kouichi Sakurai, A Fast Scalar Multiplication Method with Randomized Projective Coordinates on a Montgomery-form Elliptic Curve Secure against Side Channel Attacks, The 4th International Conference on Information Security and Cryptology (ICISC 2001), pp.428-439, 2002.01.
450. Johannes Buchmann, Kouichi SAKURAI and Tsuyoshi TAKAGI, An IND-CCA2 Public-Key Cryptosystem with Fast Decryption, 4th International Conference on Information Security and Cryptology, ICISC'01, pp.51-71, 2002.01.
451. Katsuyuki Okeya, Kouichi Sakurai, On Insecurity of the Side Channel Attack Countermeasure using Addition-Subtraction Chains under Distinguishability between Addition and Doubling, Information Security and Privacy, 7th Australasian Conference (ACISP 2002), pp.420-435, 2002.01.
452. Katsuyuki Okeya, Kouichi Sakurai, Fast Multi-Scalar Multiplication Methods on Elliptic Curves with Precomputation Strategy using Montgomery Trick, Cryptographic Hardware and Embedded System (CHES 2002), 2523, 564-578, pp.564-578, 2002.01.
453. Katsuyuki Okeya, Kouichi Sakurai, A Second-Order DPA Attack Breaks a Window-method based Countermeasure against Side Channel Attacks, Information Security Conference (ISC 2002), pp.389-401, 2002.01.
454. Kouichi SAKURAI and Tsuyoshi TAKAGI, New Semantically Secure Public-Key Cryptosystems from the RSA-Primitive, 5th International Workshop on Practice and Theory in Public Key Cryptography, PKC 2002, pp.1-16, 2002.01.
455. Soichi Furuya, Kouichi Sakurai, Single-path Authenticated-encryption Scheme Based on Universal Hashing, 9th Annual Workshop, SAC 2002, 2595, 94-109, pp.94-109, 2002.08.
456. Soichi Furuya, Kouichi Sakurai, Risks with Raw-key Masking the Security Evaluation of 2-key XCBC, Information and Communications Security, 4th International Conference, ICICS 2002, 2513, 327-341, pp.327-341, 2002.12.
457. Kenji IMAMOTO, Kouichi SAKURAI, A Scalable On-line Certified E-mail Protocol Using Password Authentication, The 3rd International Workshop on Information Security Applications (WISA2002), pp.319-331, 2002.08.
458. Kenji IMAMOTO, Kouichi SAKURAI, A Certified E-mail System With Receiver's Selective Usage of Delivery Authority, Third International Cryptology Conference in India (INDOCRYPT2002), 2551, 326-338, pp.326-338, 2002.12.
459. Jae-Gwi Choi, Kouichi Sakurai, Ji-Hwan Park, Does It Need Trusted Third Party? Design of Buyer-Seller Watermarking Protocol without Trusted Third Party, Prof. ACNS 2003, 2846, 265-279, pp.265-279, 2003.10.
460. Katsuya SUEYASU, Toshihiro TABATA, Kouichi SAKURAI, On the Security of SELinux with a Simplified Policy, Proc. of the IASTED International Conference on Communication, pp.79-84, 2003.12.
461. Manabu IWANAGA, Toshihiro TABATA, Kouichi SAKURAI, Evaluation of Anti-spam Method Combining Bayesian Filtering and Strong Challenge and Response, Proc. of IASTED Int. Conf. on Communication, Network, and Information Security (CNIS 2003), pp.214-219, 2003.12.
462. Kouichi SAKURAI and Tsuyoshi TAKAGI, A Reject Timing Attack on an IND-CCA2 Public-Key Cryptosystem, 5th International Conference on Information Security and Cryptology, ICISC 2002, 2587, 359-373, pp.359-379, 2003.01.
463. Satoshi KOGA, Kouichi SAKURAI, Decentralization Methods of Certification Authority Using the Digital Signature Schemes, 2nd Annual PKI Research Workshop, 2003.04.
464. Kazuhide Fukushima, Kouichi SAKURAI, A Software Fingerprinting Scheme for Java Using Classfiles Obfuscation, Proc. WISA 2003, 2908, 303-316, pp.303-316, 2003.08.
465. Yuki Kotegawa, Kouichi SAKURAI, A Mechanism to Detect Tampering on Mobile Agents using The Verification Agent, Proc. International Workshop on Cryptology and Network Security (CANS03), 2003.09.
466. Kenji IMAMOTO, Kouichi SAKURAI, Certified E-mail Systems Using Public Notice Board, Trust and Privacy in Digital Business (TrustBus'03), 10.1109/DEXA.2003.1232065, 460-464, pp.460-464, 2003.09.
467. Yuki KOTEGAWA, Kouichi SAKURAI, A Tampering Detection Mechanism using a Trusted Host for Mobile Agents, Proc. of the 2003 International Workshop on CRYPTOLOGY AND NETWORK SECURITY (CANS2003), pp.618-623, 2003.09.
468. Kenji IMAMOTO, Kouichi SAKURAI, Private Certified E-mail Systems with Electronic Notice Board, Proc. International Workshop on Cryptology and Network Security (CANS03), pp.726-729, 2003.09.
469. Yasuyuki Sakai, Kouichi SAKURAI, Timing Attack against Implementation of a Parallel Algorithm for Modular Exponentiation, Proc. ACNS 2003, 2846, 319-330, pp.319-330, 2003.10.
470. Satoshi Koga, Jae-Cheol Ryou, Kouichi Sakurai, Pre-production Methods of a Response to Certificates with the Common Status - Design and Theoretical Evaluation, Proc. EuroPKI 2004, 3093, 85-97, pp.85-97, 2004.06.
471. Dong-Guk Han, Jongin Lim, Kouichi Sakurai, On Security of XTR Public Key Cryptosystems Against Side Channel Attacks, Proc. ACISP 2004, pp.454-465, 2004.07.
472. Wonil Lee, Mridul Nandi, Palash Sarkar, Donghoon Chang, Sangjin Lee, Kouichi Sakura, Pseudorandomness of SPN-Type Transformations, Proc. ACISP 2004, pp.212-223, 2004.07.
473. Satoshi Koga, Kouichi SAKURAI, A Distributed Online Certificate Status Protocol with a Single Public Key, Proc. Public Key Cryptography 2004, 2947, 389-401, pp.389-401, 2004.03.
474. Satoshi Koga, Kouichi SAKURAI, A Merging Method of Certification Authorities Without Using Cross-Certifications, Proc. AINA (2) 2004, 174-177, pp.174-177, 2004.03.
475. Kenji IMAMOTO, Kouichi SAKURAI, A Design of Diffie-Hellman Based Key Exchange Using One-time ID in Pre-shared Key Model, Proc. AINA (1) 2004, 327-332, pp.327-333, 2004.03.
476. Yasuyuki Sakai, Kouichi SAKURAI, A New Attack with Side Channel Leakage During Exponent Recoding Computations, Proc. CHES 2004, 3156, 298-311, pp.298-311, 2004.01.
477. K.SAKURAI and H. Shizuya, A Structural comparison of the computational difficulty of breaking discrete log cryptosystems., J. of Cryptology, 10.1007/s001459900033, 11, 1, 29-43, Vol.11, No.1, pp. 29-43, 1998.01.
478. E. Dannoura and K.SAKURAI, An improvement of ElYaniv-Fiat-Karp-Tarpin's money-making bi-directional strategy, Information Processing Letters, 10.1016/S0020-0190(98)00032-5, 66, 1, 27-33, Vol.66, No.1, 15 , pp.27-33, 1998.04.
479. T.Itoh, M.Burmester, Y.Desmdet, K.SAKURAI, and H.Shizuya, Divertible and subliminal-free zero-knowledge proofs for languages, J. of Cryptology, 10.1007/s001459900053, 12, 3, 197-223, Vol.12, pp.197-223, 1999.01.
480. Shingo MIYAZAKI, Kouichi SAKURAI, A practical off-line digital-money system with partilly blind signatures based on the discrete logarithm problem, IEICE Transactions, E83A, 1, 106-108, Vol.E83-A, No.1, pp.106-108, 2000.01.
481. Kouichi SAKURAI, A Progress Report on Lattice Based Public-Key Cryptosystems --Theoretical Security versus Practical Cryptanalysis --, IEICE TRANSACTIONS ON INFORMATION AND SYSTEMS, E83D, 3, 570-579, Vol.E83-D No.3 pp.570-579, 2000.01.
482. Yasuyuki Sakai, Kouichi Sakurai, On the Practical Performance of Hyperelliptic Curve Cryptosystems in Software Implementation, IEICE Transactions on Fundamentals of Electronics, Communications and Computer Sciences, E83A, 4, 692-703, E83-A, No.4, 692-703, 2000.01.
483. Shingo MIYAZAKI, Kouichi SAKURAI and Moti YUNG, On Distributed Cryptographic Protocols for Threshold RSA Signing and Decrypting with No Dealer, IEICE Trans, E84A, 5, 1177-1183, Vol.E84-A, No.5, pp.1177-1183, 2001.01.
484. Kouichi SAKURAI, A Theory of Demonstrating Program Result-Correctness with Cryptographic Applications, IEICE Trans., E84D, 1, 4-14, Vol.E84-D No.1 pp.4-14, 2001.01.
485. Yasuyuki Sakai, Kouichi Sakurai, Efficient Scalar Multiplications on Elliptic Curves with Direct Computations of Several Doublings, IEICE Transactions on Fundamentals of Electronics, Communications and Computer Sciences, E84A, 1, 120-129, E84-A, No.1, 120-129, 2001.01.
486. Yasuyuki Sakai, Kouichi Sakurai, Speeding Up Elliptic Scalar Multiplication Using Multidoubling, IEICE Transactions on Fundamentals of Electronics, Communications and Computer Sciences, E85A, 5, 1075-1083, E85-A, No.5, 1075-1083, 2002.01.
487. Yasuyuki Sakai, Kouichi Sakurai, An Efficient Representation of Scalars for Simultaneous Elliptic Scalar Multiplication, IEICE Transactions on Fundamentals of Electronics, Communications and Computer Sciences, E86A, 5, 1135-1146, Vol.E86-A No.5 pp.1135-1146, 2002.01.
488. Katsuyuki Okeya, Kouichi Sakurai, A Scalar Multiplication Algorithm with Recovery of the y-Coordinate on the Montgomery Form and Analysis of Efficiency for Elliptic Curve Cryptosystems, IEICE Trans. Fundamentals, E85A, 1, 84-93, Vol.E85-A No.1, pp.84-93, 2002.01.
489. Katsuyuki Okeya, Kouichi Sakurai, Use of Montgomery Trick in Precomputation of Multi-Scalar Multiplication in Elliptic Curve Cryptosystem, IEICE Trans. Fundamentals, E86A, 1, 98-112, Vol.E86-A No.1, pp.98-112, 2003.01.
490. Katsuyuki Okeya, Kouichi Sakurai, A Simple Power Attack On a Randomized Addition-Subtraction Chains Method for Elliptic Curve Cryptosystems, IEICE Trans. Fundamentals, E86A, 5, 1171-1180, pp.1171-1180, 2003.01.
491. Kenji IMAMOTO, Kouichi SAKURAI, Analysis and Design for Private Message Board Systems, IEICE Trans. Fundamentals, E87A, 1, 204-211, Vol.E87-A, No.1,, 2004.01.
492. Shinsaku Kiyomoto, Toshiaki Tanaka, Kouichi Sakurai:, K2: A Stream Cipher Algorithm using Dynamic Feedback Control., SECRYPT 2007, 204-213, 2007.07, 2005年からKDDI研究所と共同で設計開発した
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高速ストリーム暗号 アルゴリズムであり、KDDI研と下名が共同で設計し、KDDI研によって商用化された高速ストリーム暗号アルゴリズムである。
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