Updated on 2022/10/01

写真a

 
KUSAKA Takuya
 
Organization
Faculty of Natural Science and Technology Associate Professor
Position
Associate Professor
Other name(s)
Takuya Kusaka
External link

Degree

  • Master(Engineering) ( Nara Institute of Science and Technology )

  • Doctor(Engineering) ( Nara Institute of Science and Technology )

Research Interests

  • Information Security

  • Coding Theory

  • Information Security

Research Areas

  • Manufacturing Technology (Mechanical Engineering, Electrical and Electronic Engineering, Chemical Engineering) / Communication and network engineering

Education

  • Nara Institute of Science and Technology   情報科学研究科   情報処理学

    - 1999

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    Country: Japan

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  • Nara Institute of Science and Technology    

    - 1999

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  • Kobe University    

    - 1994

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  • Kobe University   工学部   電気電子工学科

    - 1994

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    Country: Japan

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Research History

  • Okayama University   Academic Research Assembly, Academic Field of Natural Science and Technology   Lecturer

    2021.4

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  • Okayama University   The Graduate School of Natural Science and Technology   Lecturer

    2011.4 - 2021.3

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  • Okayama University   Faculty of Engineering   Lecturer

    2004.3 - 2011.3

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  • Hiroshima City University   Faculty of Information Sciences   Lecturer

    2001.4 - 2004.3

  • Hiroshima City University   Faculty of Information Science   Lecturer

    2001.4 - 2004.3

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  • Engaged in Research on the 4-th Generation

    1999 - 2001

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  • 第4世代移動通信システムの研究に従事

    1999 - 2001

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  • Mobile Communication System.

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Professional Memberships

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Committee Memberships

  • IEEE   会員  

       

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    IEEE

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  • IEEE   Member  

       

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    IEEE

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  • IEICE   Member  

       

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    IEICE

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  • 電子情報通信学会   会員  

       

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    電子情報通信学会

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  • 情報理論とその応用学会   会員  

       

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    情報理論とその応用学会

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  • SITA   Member  

       

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    SITA

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Papers

  • Consideration for affects of an xor in a random number generator using ring oscillators Reviewed

    Ryoichi Sato, Yuta Kodera, Md Arshad Ali, Takuya Kusaka, Yasuyuki Nogami, Robert H. Morelos-Zaragoza

    Entropy   23 ( 9 )   2021.9

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    Language:English   Publishing type:Research paper (scientific journal)  

    A cloud service to offer entropy has been paid much attention to. As one of the entropy sources, a physical random number generator is used as a true random number generator, relying on its irreproducibility. This paper focuses on a physical random number generator using a field-programmable gate array as an entropy source by employing ring oscillator circuits as a representative true random number generator. This paper investigates the effects of an XOR gate in the oscillation circuit by observing the output signal period. It aims to reveal the relationship between inputs and the output through the XOR gate in the target generator. The authors conduct two experiments to consider the relevance. It is confirmed that combining two ring oscillators with an XOR gate increases the complexity of the output cycle. In addition, verification using state transitions showed that the probability of the state transitions was evenly distributed by increasing the number of ring oscillator circuits.

    DOI: 10.3390/e23091168

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  • Proposal of Piccolo-CMAC for Sigfox network Reviewed

    Wataru Takehisa, Ryo Fukushima, Ryoichi Sato, Daichi Hattori, Yuta Kodera, Takuya Kusaka, Yasuyuki Nogami

    2021 36th International Technical Conference on Circuits/Systems, Computers and Communications, ITC-CSCC 2021   2021.6

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    Language:English   Publishing type:Research paper (international conference proceedings)  

    We propose a CMAC using Lightweight Blockcipher Piccolo for a well-known LPWA: Sigfox network. Increasing numbers of a device link to the Internet with LPWA, However these devices does not have adequate resources. Our proposal would be an effective security measure for limited resource IoT devices with Sigfox network. Piccolo-CMAC is implemented by employing Piccolo-80 to encrypt message without using extra resources.

    DOI: 10.1109/ITC-CSCC52171.2021.9501429

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  • Improvement of Final Exponentiation for Pairings on BLS Curves with Embedding Degree 15 Reviewed

    NANJO Yuki, SHIRASE Masaaki, KUSAKA Takuya, NOGAMI Yasuyuki

    IEICE Transactions on Fundamentals of Electronics, Communications and Computer Sciences   104 ( 1 )   315 - 318   2021

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    Language:English   Publishing type:Research paper (scientific journal)   Publisher:The Institute of Electronics, Information and Communication Engineers  

    <p>To be suitable in practice, pairings are typically carried out by two steps, which consist of the Miller loop and final exponentiation. To improve the final exponentiation step of a pairing on the BLS family of pairing-friendly elliptic curves with embedding degree 15, the authors provide a new representation of the exponent. The proposal can achieve a more reduction of the calculation cost of the final exponentiation than the previous method by Fouotsa et al.</p>

    DOI: 10.1587/transfun.2020EAL2046

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  • The Weight Distributions of the (256, k) Extended Binary Primitive BCH Codes with k≤71 and k≥187 Reviewed

    FUJIWARA Toru, KUSAKA Takuya

    IEICE Transactions on Fundamentals of Electronics, Communications and Computer Sciences   104 ( 9 )   1321 - 1328   2021

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    Language:English   Publishing type:Research paper (scientific journal)   Publisher:The Institute of Electronics, Information and Communication Engineers  

    <p>Computing the weight distribution of a code is a challenging problem in coding theory. In this paper, the weight distributions of (256, k) extended binary primitive BCH codes with k≤71 and k≥187 are given. The weight distributions of the codes with k≤63 and k≥207 have already been obtained in our previous work. Affine permutation and trellis structure are used to reduce the computing time. Computer programs in C language which use recent CPU instructions, such as SIMD, are developed. These programs can be deployed even on an entry model workstation to obtain the new results in this paper.</p>

    DOI: 10.1587/transfun.2020EAP1119

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  • Restrictions of Integer Parameters for Generating Attractive BLS Subfamilies of Pairing-Friendly Elliptic Curves with Specific Embedding Degrees Reviewed

    Nanjo Yuki, Shirase Masaaki, Kusaka Takuya, Nogami Yasuyuki

    International Journal of Networking and Computing   11 ( 2 )   383 - 411   2021

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    Language:English   Publishing type:Research paper (scientific journal)   Publisher:IJNC Editorial Committee  

    Pairings are widely used for innovative protocols such as ID-based encryption and group signature authentication. According to the recent works, the Barreto-Lynn-Scott (BLS) family of pairing-friendly elliptic curves is suggested for the pairings at the various security levels. One of the important facts is that the BLS family has fixed polynomial parameters of a field characteristic and group order in terms of an integer x_0. For practical pairing-based protocols, we have to carefully find x_0 which leads to efficient pairings, however, this search of x_0 is typically complicated. Thus, it is desired some convenient ways of finding x_0 which have advantageous for the pairings. For this reason, Costello et al. proposed simple restrictions for finding x_0 that generates the specific BLS subfamilies of curves with embedding degree k = 24 having one of the best field and curve constructions for the pairings. Since there are demands of such restrictions for the other cases of the embedding degrees, the authors extend their work and provide these for the cases of k = 2^m 3 and 3^n with arbitrary integers m, n>0 in this paper. The results will help to find new parameters which lead to one of the best performing pairings with the BLS family of curves with various k. The results also allow us to respond to change in the security levels of the pairings flexibly according to the progress in the security analyses in the future.

    DOI: 10.15803/ijnc.11.2_383

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  • Sophisticated analysis of a method to eliminate fruitless cycles for Pollard's rho method with skew Frobenius mapping over a Barreto-Naehrig curve Reviewed

    Miura Hiromasa, Kanzawa Syota, Matsumura Rikuya, Kodera Yuta, Kusaka Takuya, Nogami Yasuyuki

    International Journal of Networking and Computing   11 ( 2 )   231 - 250   2021

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    Language:English   Publishing type:Research paper (scientific journal)   Publisher:IJNC Editorial Committee  

    In this paper, the authors focus on and propose an approach to attack a kind of pairing-friendly curves, the Barreto-Naehring (BN) curve, to accelerate the evaluation of the security level concerning the elliptic curve discrete logarithm problem (ECDLP). More precisely, this paper targets the BN curve, which is known to be a pairing-friendly curve, and Pollard's rho method based on the random-walk is adopted to attack the curve.Though Pollard's rho method with skew Frobenius mapping is known to solve the ECDLP efficiently, this approach sometimes induces the unsolvable cycle, called the fruitless cycle, and such trials must restart with a different starting point. However, any effective method to eliminate such fruitless cycles has not been proposed. Therefore, the authors focus and give the sophisticated analysis to propose an effective approach to eliminate such cycles to optimize Pollard's rho method furthermore. In addition, we confirm the effectiveness of the method by applying it to a BN curve with 12, 17, and 33-bit parameters.

    DOI: 10.15803/ijnc.11.2_231

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  • Consideration of Generating Suitable Parameters for Constructing type (h, m) Gauss Period Normal Basis.

    Keiji Yoshimoto, Yuta Kodera, Takuya Kusaka, Yasuyuki Nogami

    IEEE International Conference on Consumer Electronics-Taiwan(ICCE-TW)   1 - 2   2021

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    Publishing type:Research paper (international conference proceedings)   Publisher:IEEE  

    DOI: 10.1109/ICCE-TW52618.2021.9603240

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    Other Link: https://dblp.uni-trier.de/db/conf/icce-tw/icce-tw2021.html#YoshimotoKKN21

  • An Optimal Curve Parameters for BLS12 Elliptic Curve Pairing and Its Efficiency Evaluation.

    Daichi Hattori, Yuto Takahashi, Tomoya Tatara, Yuki Nanjo, Takuya Kusaka, Yasuyuki Nogami

    IEEE International Conference on Consumer Electronics-Taiwan(ICCE-TW)   1 - 2   2021

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    DOI: 10.1109/ICCE-TW52618.2021.9602941

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    Other Link: https://dblp.uni-trier.de/db/conf/icce-tw/icce-tw2021.html#HattoriTTNKN21

  • A Proposal for Testing Physical Random Numbers Using Stochastic Process.

    Ryoichi Sato, Yuta Kodera, Takuya Kusaka, Yasuyuki Nogami

    IEEE International Conference on Consumer Electronics-Taiwan(ICCE-TW)   1 - 2   2021

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    DOI: 10.1109/ICCE-TW52618.2021.9603232

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    Other Link: https://dblp.uni-trier.de/db/conf/icce-tw/icce-tw2021.html#SatoKKN21

  • A Property Management System Using Image Recognition by YOLO.

    Taiki Miyamoto, Ryo Fukushima, Kazuaki Harada, Keiji Yoshimoto, Yuta Kodera, Takuya Kusaka, Yasuyuki Nogami

    IEEE International Conference on Consumer Electronics-Taiwan(ICCE-TW)   1 - 2   2021

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    Publishing type:Research paper (international conference proceedings)   Publisher:IEEE  

    DOI: 10.1109/ICCE-TW52618.2021.9603146

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    Other Link: https://dblp.uni-trier.de/db/conf/icce-tw/icce-tw2021.html#MiyamotoFHYKKN21

  • Path Authentication Protocol: Based on a Lightweight MAC and a Nonlinear Filter Generator Reviewed

    Y. Taketa, Y. Kodera, T. Kusaka and Y. Nogami

    Silicon Valley Cybersecurity Conference   38 - 48   2020.12

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  • Improvement of Bit Distribution of Binary Sequence Generated by Alternative Trace Map Function Reviewed

    Fatema Akhter, Tomoya Tatara, Yasuyuki Nogami, Takuya Kusaka, Nobuo Funabiki

    Proceedings - 2020 8th International Symposium on Computing and Networking Workshops, CANDARW 2020   302 - 306   2020.11

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    Pseudo random binary sequences have been widely used in cryptographic applications due to their speedy construction, reproducibility and characteristics like true random sequence. Realization of modern cryptographic application and mathematical tools is inconceivable without random sequences. Previously, we proposed an alternative trace map function for generation of a pseudo random binary sequence that has long period, good correlation characteristics and high linear complexity that are attractive for security applications. However, it was found that the distribution of bits in sequence is not uniform which may lead to failure in randomness. In this paper, we propose a uniformization method using power of primitive root to improve uniformity of bit distribution in the sequence. Sequence of different lengths is generated using proposed sequence to verify the efficiency of the proposed uniformization method. By analyzing the bit distribution of generated sequences for different length of patterns, we show that the proposal achieves bit uniformity while maintaining randomness of the sequence.

    DOI: 10.1109/CANDARW51189.2020.00066

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  • An Approach for Attacking Speck on Microcontroller with Correlation Power Analysis. Reviewed

    Jianjie Tang, Kengo Iokibe, Takuya Kusaka, Yasuyuki Nogami

    Eighth International Symposium on Computing and Networking Workshops   368 - 372   2020.11

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    Language:English   Publishing type:Research paper (international conference proceedings)   Publisher:IEEE  

    DOI: 10.1109/CANDARW51189.2020.00076

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    Other Link: https://dblp.uni-trier.de/db/conf/ic-nc/candar2020w.html#TangIKN20

  • Analysis of a method to eliminate fruitless cycles for Pollard’s rho method with skew Frobenius mapping over a Barreto-Naehrig curve Reviewed

    Hiromasa Miura, Rikuya Matsumura, Takuya Kusaka, Yasuyuki Nogami

    Proceedings - 2020 8th International Symposium on Computing and Networking, CANDAR 2020   160 - 166   2020.11

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    Pollard’s rho method is one of the most efficient methods for solving elliptic curve discrete logarithm problem (ECDLP) in elliptic curve cryptography. Pollard’s rho method with skew Frobenius mapping can solve ECDLP over a Barreto-Naehrig (BN) curve efficiently. Pollard’s rho method may result in an unsolvable cycle called a fruitless cycle. When a random walk pass results in a fruitless cycle, the random walk pass must restart with a different starting point. However, an effective method for eliminating the fruitless cycle has been not proposed yet. This paper proposes a method for eliminating the fruitless cycle in Pollard’s rho method with skew Frobenius mapping. In addition, the authors apply the proposed method to a BN curve with 17-bit parameters and confirm the effectiveness.

    DOI: 10.1109/CANDAR51075.2020.00029

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  • Specific Congruence Classes of Integer Parameters for Generating BLS Curves for Fast Pairings. Reviewed

    Yuki Nanjo, Masaaki Shirase, Takuya Kusaka, Yasuyuki Nogami

    Eighth International Symposium on Computing and Networking Workshops   348 - 354   2020.11

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    Language:English   Publishing type:Research paper (international conference proceedings)   Publisher:IEEE  

    DOI: 10.1109/CANDARW51189.2020.00073

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    Other Link: https://dblp.uni-trier.de/db/conf/ic-nc/candar2020w.html#NanjoSKN20

  • Equivalent Keys of a Nonlinear Filter Generator Using a Power Residue Symbol. Reviewed

    Yuta Kodera, Yuki Taketa, Takuya Kusaka, Yasuyuki Nogami, Satoshi Uehara

    Advances in Information and Computer Security - 15th International Workshop on Security(IWSEC)   23 - 36   2020.9

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    DOI: 10.1007/978-3-030-58208-1_2

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    Other Link: https://dblp.uni-trier.de/db/conf/iwsec/iwsec2020.html#KoderaTKNU20

  • Implementation and Evaluation of an Efficient MAC Based on OMAC for CAN on 8-Bit Microcomputer Reviewed

    Yuta Fujioka, Hiroto Ogura, Yuki Ueno, Takuya Kusaka, Yasuyuki Nogami

    ITC-CSCC 2020 - 35th International Technical Conference on Circuits/Systems, Computers and Communications   342 - 347   2020.7

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    In this study, a new MAC based on OMAC is implemented in Arduino Uno. In addition, a function to update the common key based on pseudo-random numbers is additionally implemented. A re-verification function of the MAC value on the receiving ECU is also implemented. Similarly, these features have been implemented for the Raspberry Pi. Communication with Arduino is possible. The time taken to calculate the MAC and the time required to update the key are measured for the Arduino and Raspberry Pi, respectively. As a result, both of the OMAC processing time and the key update time in both of the microcomputers satisfied a time constraints.

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  • Electrical Falsification of CAN Data by Magnetic Coupling Reviewed

    H. Ogura,R. Isshiki,K. Iokibe,Y. Kodera,T. Kusaka and Y. Nogami

    International Technical Conference on Circuits/Systems, Computers and Communications   348 - 359   2020.6

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  • Implementation and Evaluation of Ate Pairings on Elliptic Curves with Embedding Degree 10 Applied Type-II All-One Polynomial Extension Field of Degree 5 Reviewed

    Rikuya Matsumura, Yuto Takahashi, Yuki Nanjo, Takuya Kusaka, Yasuyuki Nogami

    35TH INTERNATIONAL TECHNICAL CONFERENCE ON CIRCUITS/SYSTEMS, COMPUTERS AND COMMUNICATIONS (ITC-CSCC 2020)   336 - 341   2020.6

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    Language:English   Publishing type:Research paper (international conference proceedings)   Publisher:IEEE  

    Pairing-based cryptography has received much attention as an encryption method for realizing advanced cryptography such as ID-based encryption and searchable encryption. In a pairing-friendly elliptic curve of embedding degree 10, calculation cost of multiplication and squaring on extension fields of degree 5 are related to efficiency of pairing. Therefore, it is necessary to select an efficient multiplication and squaring algorithms on the extension field of degree 5. To apply these algorithms, the authors implement a pairing on an elliptic curve of embedding degree 10 with type-II all-one polynomial extension field (AOPF) of degree of 5 and optimal extension field (OEF) of degree of 5. As a result, the computational complexity of pairing with the expanded AOPF of degree 5 are almost 7.4% efficient than that of the expanded OEF of degree 5.

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  • An Implementation and Evaluation of a Pairing on Elliptic Curves with Embedding Degree 14 Reviewed

    Zihao Song, Rikuya Matsumura, Yuto Takahashi, Yuki Nanjo, Takuya Kusaka, Yasuyuki Nogami, Tsutomu Matsumoto

    35TH INTERNATIONAL TECHNICAL CONFERENCE ON CIRCUITS/SYSTEMS, COMPUTERS AND COMMUNICATIONS (ITC-CSCC 2020)   293 - 298   2020.6

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    Language:English   Publishing type:Research paper (international conference proceedings)   Publisher:IEEE  

    As the computer architecture technology evolves, communication protocols have been demanded not only having reliable security but also flexible functionality. Advanced cryptography has been expected as a new generation cryptography which suffices such the requirements. A pairing is one of the key technologies of the cryptography and the pairing has been known as having a substantial amount of construction parameters. Recently, the elliptic curve with embedding degree 14 is evaluated as one of the efficient curves for pairing. In the paper, we implement an optimal ate pairing on the elliptic curve by applying several variants of multiplication algorithms of extension field of degree 7 on multiple devices. The best multiplication algorithm among the candidates is derived. Besides, for efficient calculations, we propose a pseudo 7-sparse algorithm and a fast calculation method of final exponentiation. As a result, we discover the proper multiplication algorithm bases on the rate of addition and multiplications on several different computer platforms. Our proposed pseudo 7-sparse algorithm is approximately 1.54% faster than a regular algorithm on almost all tested platforms. Eventually, for the total execution time of pairing we record 9.33ms on Corei5-9500.

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  • An Explicit Formula of Cyclotomic Cubing Available for Pairings on Elliptic Curves with Embedding Degrees of Multiple of Three Reviewed

    Yuki Nanjo, Masaaki Shirase, Takuya Kusaka, Yasuyuki Nogami

    35TH INTERNATIONAL TECHNICAL CONFERENCE ON CIRCUITS/SYSTEMS, COMPUTERS AND COMMUNICATIONS (ITC-CSCC 2020)   288 - 292   2020.6

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    Language:English   Publishing type:Research paper (international conference proceedings)   Publisher:IEEE  

    Bilinear pairings are widely used for innovative protocols such as ID-based encryption and group signature authentication. According to the current research of the pairings, not only families of pairing-friendly elliptic curves with embedding degrees of multiple of four or six but also that of multiple of three are attractive choices for practical pairings. However, the pairings on such the elliptic curves cannot benefit from an efficient performing squaring available in a cyclotomic subgroup which plays an important role in fast final exponentiation. As one of the candidates of replacements of the squaring, the authors consider an efficient performing cubing available in the cyclotomic subgroup.

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  • A Technique for Fast Miller's Algorithm of Ate Pairings on Elliptic Curves with Embedding Degrees of Multiple of Three Reviewed

    Yuki Nanjo, Masaaki Shirase, Takuya Kusaka, Yasuyuki Nogami

    35TH INTERNATIONAL TECHNICAL CONFERENCE ON CIRCUITS/SYSTEMS, COMPUTERS AND COMMUNICATIONS (ITC-CSCC 2020)   283 - 287   2020.6

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    Language:English   Publishing type:Research paper (international conference proceedings)   Publisher:IEEE  

    Bilinear pairings are widely used for innovative protocols such as ID-based encryption and group signature authentication. According to the current research of the pairings, not only families of pairing-friendly elliptic curves with embedding degrees of multiple of four or six but also that of multiple of three can realize efficient pairings. However, the range of the practical choices of the elliptic curves with embedding degrees of multiple of three is more restricted than that of even embedding degrees by an efficiency reason for the computation of Miller's algorithm with a signed binary representation of a loop parameter. To ease the restriction, the authors propose to compute the Miller's algorithm by swapping the sign of the loop parameter without performance degradation for the ate pairing on such the elliptic curves.

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  • A Performance Analysis and Evaluation of SIDH Applied Several Implementation-Friendly Quadratic Extension Fields Reviewed

    Nanjo Yuki, Shirase Masaaki, Kusaka Takuya, Nogami Yasuyuki

    International Journal of Networking and Computing   10 ( 2 )   227 - 241   2020

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    It is well-known that quadratic extension fields (QEFs) based on optimal extension fields (OEFs) are typically used for supersingular isogeny Diffie-Hellman (SIDH) key exchange protocol. On the other hand, there is a possibility of the performance improvement of SIDH by employing other attractive choices of QEFs with efficient performing arithmetics which are based on all-one polynomial extension fields (AOPFs) and extension fields with normal basis representation (EFNs). Thus, the authors confirm that the applicability of the new candidates of QEFs for SIDH and evaluate SIDH applied the possible choices of QEFs. As a result of the experiment, the authors found that the performances of SIDH applied the QEFs based on AOPF and EFN are comparable to that of the previous QEF. Moreover, one of the QEFs based on EFN result in a new efficient implementation of the SIDH with SIDH-friendly prime given as p= 2^{e_A}3^{e_B}f+1 where e_A, e_B and $f$ are positive integers.

    DOI: 10.15803/ijnc.10.2_227

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  • A Construction Method of an Isomorphic Map between Quadratic Extension Fields Applicable for SIDH Reviewed

    NANJO Yuki, SHIRASE Masaaki, KUSAKA Takuya, NOGAMI Yasuyuki

    IEICE Transactions on Fundamentals of Electronics, Communications and Computer Sciences   103 ( 12 )   1403 - 1406   2020

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    Language:English   Publishing type:Research paper (scientific journal)   Publisher:The Institute of Electronics, Information and Communication Engineers  

    <p>A quadratic extension field (QEF) defined by <i>F</i><sub>1</sub> = F<sub>p</sub>[α]/(α<sup>2</sup>+1) is typically used for a supersingular isogeny Diffie-Hellman (SIDH). However, there exist other attractive QEFs <i>F<sub>i</sub></i> that result in a competitive or rather efficient performing the SIDH comparing with that of <i>F</i><sub>1</sub>. To exploit these QEFs without a time-consuming computation of the initial setting, the authors propose to convert existing parameter sets defined over <i>F</i><sub>1</sub> to <i>F<sub>i</sub></i> by using an isomorphic map <i>F</i><sub>1</sub> → <i>F<sub>i</sub></i>.</p>

    DOI: 10.1587/transfun.2020TAL0002

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  • A Parallel Blum-Micali Generator Based on the Gauss Periods Reviewed

    Yuta Kodera, Tomoya Tatara, Takuya Kusaka, Yasuyuki Nogami, Satoshi Uehara

    IEICE Proceeding Series   ( 65 )   447 - 450   2020

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    Language:English   Publishing type:Research paper (international conference proceedings)   Publisher:The Institute of Electronics, Information and Communication Engineers  

    DOI: 10.34385/proc.65.C04-1

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  • Evaluating Side-Channel Resistance Using Low Order Rational Points Against Curve25519 and an Associated Quadratic Twist Reviewed

    Yoshimoto Keiji, Uetake Yoshinori, Kodera Yuta, Kusaka Takuya, Nogami Yasuyuki

    International Journal of Networking and Computing   10 ( 2 )   144 - 158   2020

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    Language:English   Publishing type:Research paper (scientific journal)   Publisher:IJNC Editorial Committee  

    IoT devices contribute to improving the mechanism of a system as edge devices for data sharing and automation of industrials. However, such devices are often being a target of an attacker due to their simple architecture and the lack of resources so as to protect data confidentiality using cryptosystems. In addition, although Curve25519 has been used in various security protocols and known to work even on IoT devices efficiently, the curve inherits the low order points hidden inside of the Edward curves. In this paper, the authors demonstrate side-channel attacks against Curve25519 by focusing on the points of order 4 and 8. We choose the order 4 point which does not exist on Curve25519, that exists on the twisted curve of Curve25519. More precisely, the rational point used in this paper is given by (x,y)=(-1,0) in affine coordinates. In addition, the order 8 point appears to be a high order rational point. The results reveal that the rational points might be a threat to key extraction and it demands us to find further countermeasures.

    DOI: 10.15803/ijnc.10.2_144

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  • the Inverse of a Masked Vector in an Isomorphic GF for Perfectly Masked S-Box Reviewed

    Y. Kodera, Y. Taketa, T. Kusaka and Y. Nogami

    International Symposium on Computing and Networking   157 - 163   2019.11

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  • A Preliminary Study on Methods to Eliminate Short Fruitless Cycles for Pollard's Rho Method for ECDLP over BN Curves. Reviewed

    Hiromasa Miura, Rikuya Matsumura, Ken Ikuta, Sho Joichi, Takuya Kusaka, Yasuyuki Nogami

    Seventh International Symposium on Computing and Networking Workshops   353 - 359   2019.11

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    Language:English   Publishing type:Research paper (international conference proceedings)   Publisher:IEEE  

    DOI: 10.1109/CANDARW.2019.00068

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    Other Link: https://dblp.uni-trier.de/db/conf/ic-nc/candar2019w.html#MiuraMIJKN19

  • A Side-Channel Attack Using Order 8 Rational Points against Curve25519 on an 8-Bit Microcontroller Reviewed

    Yoshinori Uetake, Keiji Yoshimoto, Yuta Kodera, Leo Weissbart, Takuya Kusaka, Yasuyuki Nogami

    Proceedings - 2019 7th International Symposium on Computing and Networking, CANDAR 2019   225 - 231   2019.11

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    Among the increasing evolution of IoT devices, practical applications need reliable secure protocols to communicate with each other. A major issue for modern cryptosystems is an implementation of secure and trustworthy mechanisms to rely on. A side-channel attack against these cryptosystems may overturn the guarantee of security against conventional cyber-attacks. Elliptic curve cryptography is public-key cryptography based on elliptic curves, and one of the well-known curves is Curve25519 which is used for TLS protocols as a recommended curve. This curve is mainly implemented on limited resource devices such as microcontrollers. However, this curve poses a weakness for low-order points during a Diffie-Hellman key exchange is employed. This research demonstrates possible exploitation of a threat of order 8 rational points of Curve25519 and shows results of the side-channel attacks using order 8 rational points on an embedded system. The results indicate the order 8 rational points might be applied to key extraction as attacker sides.

    DOI: 10.1109/CANDAR.2019.00037

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  • Evaluating a Side-Channel Resistance against Order 4 Rational Points in Arduino Cryptography Library. Reviewed

    Keiji Yoshimoto, Yoshinori Uetake, Yuta Kodera, Takuya Kusaka, Yasuyuki Nogami

    2019 Seventh International Symposium on Computing and Networking(CANDAR)   245 - 250   2019.11

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    DOI: 10.1109/CANDAR.2019.00040

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  • Mutual Relationship between the Neural Network Model and Linear Complexity for Pseudorandom Binary Number Sequence. Reviewed

    Yuki Taketa, Yuta Kodera, Shogo Tanida, Takuya Kusaka, Yasuyuki Nogami, Norikazu Takahashi, Satoshi Uehara

    Seventh International Symposium on Computing and Networking Workshops   394 - 400   2019.11

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    DOI: 10.1109/CANDARW.2019.00074

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  • A Performance Analysis and Evaluation of SIDH with Implementation-Friendly Classes of Quadratic Extension Fields. Reviewed

    Yuki Nanjo, Masaaki Shirase, Takuya Kusaka, Yasuyuki Nogami

    2019 Seventh International Symposium on Computing and Networking(CANDAR)   178 - 184   2019.11

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    DOI: 10.1109/CANDAR.2019.00030

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  • Binary sequence generated by alternative trace map function and its properties Reviewed

    Fatema Akhter, Yasuyuki Nogami, Takuya Kusaka, Yuki Taketa, Tomoya Tatara

    Proceedings - 2019 7th International Symposium on Computing and Networking Workshops, CANDARW 2019   408 - 411   2019.11

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    In this paper, we propose a new pseudo random binary sequence generated from a primitive polynomial over an extension field. The sequence has maximum period and high linear complexity suitable for security applications. While generation, a new mapping function is proposed which is faster than conventional trace map and translates extension field elements to prime field elements. The output of mapping function is a p-ary sequence with elements 0~ (p-1) that is balanced in pattern distribution and has ideal autocorrelation. Then, a binarization method is utilized to derive binary sequence from p-ary sequence. Period, autocorrelation, linear complexity and computation time of the proposed sequence are studied and experimental results are presented. Finally, the efficiency of the proposal is verified by comparing with existing sequences in terms of period, linear complexity and generation time for sequences of different length.

    DOI: 10.1109/CANDARW.2019.00076

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  • Updating A Secret Key for MAC Implemented on CAN Using Broadcast Encryption Scheme Reviewed

    T. Tatara, H. Ogura, YKodera, T. Kusaka and YNogami

    International Technical Conference on Circuits/Systems, Computers and Communications   166 - 169   2019.6

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  • A Comparison of Relic-toolkit and ELiPS Libraries for a Pairing-based Homomorphic Encryption Reviewed

    9.T. Kanenari, Y. Takahashi, Y. Hashimoto, Y. Kodera, T. Kusaka, Y. Nogami and T. Nakanishi

    International Technical Conference on Circuits/Systems, Computers and Communications   158 - 165   2019.6

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  • Analysis of the fruitless cycle of Pollard's rho method based attack for solving ECDLP over Barreto-Naehrig curves Reviewed

    Hiromasa Miura, Ken Ikuta, Sho Joichi, Takuya Kusaka, Yasuyuki Nogami

    34th International Technical Conference on Circuits/Systems, Computers and Communications, ITC-CSCC 2019   162 - 165   2019.6

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    This paper focuses on the computational security of elliptic curve discrete logarithm (ECDLP), which can evaluate by an actual attack. The authors apply Pollard's rho method to a Barreto-Naehrig curve with minimum parameters for solving an ECDLP. An analysis of the structure for all combinations of a select of seed and starting points are given. Then, we propose the method for selecting a set of efficient seed points for a random walk for the rho method.

    DOI: 10.1109/ITC-CSCC.2019.8793449

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  • An Analysis of Computational Complexity of Low Level Quantizers for Block Turbo Decoding for Product Codes of Binary Linear Code. Reviewed

    Shinichi Kageyama, Ken Ikuta, Yuki Nanjo, Yuta Kodera, Takuya Kusaka, Yasuyuki Nogami

    Seventh International Symposium on Computing and Networking Workshops   425 - 429   2019.6

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    DOI: 10.1109/CANDARW.2019.00080

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  • An Implementation and Evaluation of Pairing Library ELiPS for BLS Curve with Several Techniques Reviewed

    Y. Takahashi, Y. Nanjo, T. Kusaka, Y. Nogami, T, Kanenari and T. Tatara

    International Technical Conference on Circuits/Systems, Computers and Communications   170 - 173   2019.6

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  • A Study on Low Level Quantizers for Block Turbo Decoding for Product Codes of Binary Linear Code Reviewed

    S. Kageyama, K. Ikuta, T. Kusaka and Y. Nogami

    International Technical Conference on Circuits/Systems, Computers and Communications   584 - 587   2019.6

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  • Boundary for the Linear Complexity of Well Balanced NTU Reviewed

    Yuta Kodera, Takuya Kusaka, Yasuyuki Nogami

    2019 IEEE International Conference on Consumer Electronics - Taiwan, ICCE-TW 2019   2019.5

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    A pseudorandom sequence has an inseparable role in various types of security applications. Especially, the linear complexity of a sequence is a measure of the randomness that should be large for secureness of a system. This paper considers the boundary of linear complexity of a geometric sequence called NTU sequence which is generated with a uniformization technique.

    DOI: 10.1109/ICCE-TW46550.2019.8992029

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  • A Consideration on Generating Uniform Binary Sequence with High Linear Complexity Reviewed

    T. Tatara, Y. Kodera, T. Kusaka and Y. Nogami

    International Conference on Consumer Electronics   2019.5

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  • NIST Statistical Test for Random Sequence Generated by Möbius Function Reviewed

    Fatema Akhter, Yuta Kodera, Yasuyuki Nogami, Takuya Kusaka

    2019 IEEE International Conference on Consumer Electronics - Taiwan, ICCE-TW 2019   2019.5

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    Random sequences play important roles in many security applications. Several security protocols have been developed based on random sequences. Hence, their generation is one of the topic of interests among many cryptographic researchers. Previously, the authors proposed a pseudo random sequence over odd characteristic field which is generated by applying primitive polynomial, trace function and Mobius function. Some important properties such as period, autocorrelation and cross-correlation have been presented in previous work. Randomness is generally measured by statistical tests and NIST Statistical Test Suite (NIST STS) is one of the most popular tools for randomness analysis. In this work, the randomness of the generated sequence is investigated by NIST STS.

    DOI: 10.1109/ICCE-TW46550.2019.8992033

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  • Efficient ate-based pairing over the attractive classes of BN curves Reviewed

    Yuki Nanjo, Md Al Amin Khandaker, Masaaki Shirase, Takuya Kusaka, Yasuyuki Nogami

    Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics)   11402 LNCS   55 - 67   2019.4

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    This paper proposes two attractive classes of Barreto-Naehrig curve for ate-based pairing by imposing certain condition χ ≡ 7, 11 (mod 12) on the integer χ that parameterizes the curve settings. The restriction results in an unparalleled way to determine a BN curve, its twisted curve coefficients, and obvious generator points. The proposed χ ≡ 11 (mod 12) are found to be more efficient than χ ≡ 7 (mod 12) together with pseudo 8-sparse multiplication in Miller's algorithm. The authors also provide comparative implementations for the proposal.

    DOI: 10.1007/978-3-030-17982-3_5

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  • Algebraic Group Structure of the Random Number Generator: Theoretical Analysis of NTU Sequence(s) Reviewed

    KODERA Yuta, ALI Md. Arshad, MIYAZAKI Takeru, KUSAKA Takuya, NOGAMI Yasuyuki, UEHARA Satoshi, MORELOS-ZARAGOZA Robert H.

    IEICE Transactions on Fundamentals of Electronics, Communications and Computer Sciences   102 ( 12 )   1659 - 1667   2019

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    <p>An algebraic group is an essential mathematical structure for current communication systems and information security technologies. Further, as a widely used technology underlying such systems, pseudorandom number generators have become an indispensable part of their construction. This paper focuses on a theoretical analysis for a series of pseudorandom sequences generated by a trace function and the Legendre symbol over an odd characteristic field. As a consequence, the authors give a theoretical proof that ensures a set of subsequences forms a group with a specific binary operation.</p>

    DOI: 10.1587/transfun.E102.A.1659

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  • Development of Collision-Based Attack Practicum for Security Evaluation by Using Next Generation Cryptosystem in IoT Era. Invited

    NOGAMI Yasuyuki, KUSAKA Takuya, KOBAYASHI Kazuya, HASHIMOTO Yuta

    Computer Software   36 ( 1 )   95 - 100   2019

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    <p>In the IoT era when a device is connected via the Internet, we can enjoy a great deal of convenience with the use of such devices, but a large number of users are not concerned about the attack from a third party. It is also meaningful for the user to have such a consciousness, but the person providing devices needs more specialized knowledge and awareness of the security. For such demands, a special education program called enPiT is held to provide an opportunity for undergraduate students to learn about cutting-edge information technologies and aims to cultivate human resources who have acquired the ability to solve specific problems in society. In this paper, we introduce the contents of "enPiT-Security advanced PBL exercise G" held in Okayama University and describe the helpfulness of the exercise and room for improvement based on the students' comments.</p>

    DOI: 10.11309/jssst.36.95

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  • Advanced Searchable Encryption: An Adaptively Secure Keyword Search for Matrix-type Storages Reviewed

    Kodera Yuta, Kuribayashi Minoru, Kusaka Takuya, Nogami Yasuyuki

    International Journal of Networking and Computing   9 ( 2 )   171 - 187   2019

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    IoT technologies and cloud storages have been developed remarkably, and many types of data including private information have been gradually outsourced. For such a situation, new convenient functionalities such as arithmetic and a keyword search over ciphertexts are required to allow users to obtain information without leaking queried results, contents of ciphertext, and so on. Especially, searchable encryptions have been paid much attention to realize a keyword search on an encrypted domain. In addition, an architecture of searchable symmetric encryption (SSE) is a suitable and efficient solution for data outsourcing. In this paper, we focus on an SSE scheme which employs a secure index for searching a keyword. In conventional studies, it has been widely considered that the scheme searches whether a queried keyword is contained in encrypted documents or not. On the other hand, we additionally take into account the location of the queried keyword in the documents by targeting a matrix-type data format. The method enables an administrator to search personal information listed per line or column in CSV-like format data.

    DOI: 10.15803/ijnc.9.2_171

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  • Distribution of Bit Patterns in Binary Sequence Generated Over Sub Extension Field Reviewed

    Md. Arshad Ali, Yuta Kodera, Takuya Kusaka, Yasuyuki Nogami, Satoshi Uehara, Robert H. Morelos-Zaragoza

    Advances in Science, Technology and Engineering Systems Journal   4 ( 2 )   370 - 379   2019

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    DOI: 10.25046/aj040246

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  • Well Balanced Multi-value Sequence and its Properties Over Odd Characteristic Field Reviewed

    Md. Arshad Ali, Yuta Kodera, Md. Fazle Rabbi, Takuya Kusaka, Yasuyuki Nogami, Satoshi Uehara, Robert H. Morelos-Zaragoza

    Advances in Science, Technology and Engineering Systems Journal   4 ( 4 )   188 - 196   2019

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    DOI: 10.25046/aj040423

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  • Multi-Value Sequence Generated over Sub Extension Field and Its Properties Reviewed

    Md. Arshad Ali, Yuta Kodera, Takuya Kusaka, Satoshi Uehara, Yasuyuki Nogami, Robert H. Morelos-Zaragoza

    Journal of Information Security   10 ( 03 )   130 - 154   2019

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    DOI: 10.4236/jis.2019.103008

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  • Advanced searchable encryption: Keyword search for matrix-type storage

    Yuta Kodera, Minoru Kuribayashi, Takuya Kusaka, Yasuyuki Nogami

    Proceedings - 2018 6th International Symposium on Computing and Networking Workshops, CANDARW 2018   292 - 297   2018.12

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    The recent development of IoT technologies and cloud storages, many types of information including private information have been gradually outsourced. For such a situation, new convenient functionalities such as arithmetic and keyword search on ciphertexts are required to allow users to retrieve information without leaking any information. Especially, searchable encryptions have been paid much attention to realize a keyword search on an encrypted domain. In addition, an architecture of searchable symmetric encryption (SSE) is a suitable and efficient solution for data outsourcing. In this paper, we focus on an SSE scheme which employs a secure index for searching a keyword with optimal search time. In the conventional studies, it has been widely considered that the scheme searches whether a queried keyword is contained in encrypted documents. On the other hand, we additionally take into account the location of a queried keyword in documents by targeting a matrix-type data format. It enables a manager to search personal information listed per line or column in CSV-like format data.

    DOI: 10.1109/CANDARW.2018.00061

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  • Consideration of efficient pairing applying two construction methods of extension fields Reviewed

    Yuki Nanjo, Md Al Amin Khandaker, Takuya Kusaka, Yasuyuki Nogami

    Proceedings - 2018 6th International Symposium on Computing and Networking Workshops, CANDARW 2018   445 - 451   2018.12

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    In recent years, many innovative cryptography protocols based on the pairing. Finding out an efficient extension field construction is one of the prerequisites for a practical pairing implementation. The author tries to find an elegant extension field construction which will result in efficient pairing over Barreto-Naehrig (BN) curve. In this paper, two construction methods are considered for extension field of degree 12, and one of them results in an efficient exponentiation and the other enables to compute faster Miller loop than the former one. Therefore, a method which uses a basis conversion matrix between the two extension field is proposed. In comparison to the performance of Aranha et al.'s towering, the proposed implementation results in the efficient exponentiation in a multiplicative group, although pairing cost is slightly increased.

    DOI: 10.1109/CANDARW.2018.00087

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  • Bit distribution of binary sequence generated by trace function and Legendre symbol over sub extension field Reviewed

    M. Arshad Ali, Yuta Kodera, Shoji Heguri, Takuya Kusaka, Satoshi Uehara, Robert H. Morelos-Zaragoza

    ACM International Conference Proceeding Series   92 - 96   2018.11

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    The authors of this paper have observed the distribution of bit patterns property of a binary sequence which is generated by using a primitive polynomial, trace function, and Legendre symbol over the sub extension field. However, one of the most important measure for evaluating the randomness of a sequence which is so called the distribution of bit patterns still has not been investigated. This paper focused on the distribution of bit patterns based on some experimental results. After observing many experimental results, the authors found that the number of appearance of each bit pattern is related to the number of zeros contained in each bit pattern. Furthermore, the authors formulated an equation to explain the distribution of bit patterns in a binary sequence.

    DOI: 10.1145/3301551.3301562

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  • A Construction of a Keyword Search to Allow a Partial Matching with a Block Cipher Reviewed

    Y. Kodera, M. Kuribayashi, T. Kusaka and Y. Nogami

    Proceedings of the World Conference on Information Security Applications   2018.11

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  • Side-Channel Attack using Order 4 Element against Curve25519 on ATmega328P Reviewed

    Y. Uetake, A. Sanada, L. Weissbart, T. Kusaka, S. Dequesne and Y. Nogami

    Proceedings of the International Symposium on Information Theory and Its Applications   2018.11

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  • A Study on the Parameter of the Distinguished Point Method in Pollard's Rho Method for ECDLP Reviewed

    Ken Ikuta, Sho Joichi, Kazuya Kobayashi, Md Al Amin Khandaker, Takuya Kusaka, Yasuyuki Nogami

    Proceedings of 2018 International Symposium on Information Theory and Its Applications, ISITA 2018   628 - 632   2018.11

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    In this research, the choice of the parameter for a method to generate distinguished rational points in Pollard's Rho method to solve the elliptic curve discrete logarithm problem for Barreto-Naehrig (BN) curves is shown. The structures of random walk paths are confirmed by experiments for several BN curves. From the results, the authors clarify the conditions in which the Rho method does not stop during an attack, and the authors also show an indication for the choice of the parameter for the method to generate distinguished points with large bits of ECDLP.

    DOI: 10.23919/ISITA.2018.8664405

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  • A Study on the Parameter Size of the Montgomery Trick for ECDLP Reviewed

    K. Ikuta, S. Joichi, K. Kobayashi, M. A. Khandaker, T. Kusaka and Y. Nogami

    Proceedings of the International Symposium on Information Theory and Its Applications   2018.11

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  • Design of a message authentication protocol for CAN FD based on Chaskey lightweight MAC Reviewed

    G. Carel, R. Isshiki, T. Kusaka, Y. Nogami and S. Araki

    Proceedings of the International Symposium on Computing and Networking   2018.11

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  • A Comparative Implementation of GLV Technique on KSS-16 Curve Reviewed

    M. A. Khandaker, Y. Nanjo, T. Kusaka and Y. Nogami

    Proceedings of the International Symposium on Computing and Networking   2018.11

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  • Distribution of Digit Patterns in Multi-Value Sequence over the Odd Characteristic Field

    Yuta KODERA, Takeru MIYAZAKI, Md. Al-Amin KHANDAKER, Md. Arshad ALI, Takuya KUSAKA, Yasuyuki NOGAMI, Satoshi UEHARA

    IEICE Transactions on Fundamentals of Electronics, Communications and Computer Sciences   E101.A ( 9 )   1525 - 1536   2018.9

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    DOI: 10.1587/transfun.e101.a.1525

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  • An Extended Generalized Minimum Distance Decoding for Binary Linear Codes on a 4-Level Quantization over an AWGN Channel. Reviewed

    Shunsuke Ueda, Ken Ikuta, Takuya Kusaka, Md. Al-Amin Khandaker, Ali Md. Arshad, Yasuyuki Nogami

    IEICE Trans. Fundam. Electron. Commun. Comput. Sci.   E101-A ( 8 )   1235 - 1244   2018.8

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    DOI: 10.1587/transfun.E101.A.1235

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  • Linear Complexity of Pseudo-random Binary Sequence Generated Over Proper Sub Extension Field Reviewed

    M. A. Ali, Y. Kodera, T. Kusaka, T. Miyazaki, Y. Nogami, S. Uehara and R. H. M. Zaragoza

    Proceedings of the International Technical Conference on Circuits/Systems, Computers and Communications   448 - 451   2018.7

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  • Evaluating the Maximum Order Complexity of a Uniformly distributed Sequence over Odd Characteristic Reviewed

    Y. Kodera, T. Kusaka, T. Miyazaki, Y. Nogami, S. Uehara and R. H. M. Zaragoza

    Proceedings of the International Conference on Consumer Electronics-Taiwan   2018.5

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  • A Consideration of an Efficient Arithmetic over the Extension Field of Degree 3 for Elliptic Curve Pairing Cryptography Reviewed

    Xin Li, Yuta Kodera, Yoshinori Uetake, Takuya Kusaka, Yasuyuki Nogami

    2018 IEEE International Conference on Consumer Electronics-Taiwan, ICCE-TW 2018   2018.5

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    This paper presents an efficient arithmetic in extension field based on Cyclic Vector Multiplication Algorithm that reduces calculation costs over cubic extension for elliptic curve pairing cryptography. In addition, we evaluate the calculation costs compared to Karatsuba-based method.

    DOI: 10.1109/ICCE-China.2018.8448573

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  • Analysis of a sufficient condition on the optimality of a decoded codeword of soft-decision decodings for binary linear codes on a 4-level quantization over an AWGN channel Reviewed

    Takuya Kusaka

    IEICE Transactions on Fundamentals of Electronics, Communications and Computer Sciences   E101-A ( 3 )   570 - 576   2018.3

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    In this paper, a study of a sufficient condition on the optimality of a decoded codeword of soft-decision decodings for binary linear codes is shown for a quantized case. A typical uniform 4-level quantizer for soft-decision decodings is employed for the analysis. Simulation results on the (64,42,8) Reed-Muller code indicates that the condition is effective for SN ratios at 3 [dB] or higher for any iterative style optimum decodings.

    DOI: 10.1587/transfun.E101.A.570

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  • Efficient pairing-based cryptography on raspberry Pi

    Yuki Nanjo, Md Al Amin Khandaker, Takuya Kusaka, Yasuyuki Nogami

    Journal of Communications   13 ( 2 )   88 - 93   2018.2

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    In the age of IoT, pairing-based cryptography (PBC) can play an important role as a public key cryptography since it enables several innovative protocols such as anonymous encryption, certificate less authentication and so on. However, due to the computation complexity, PBC is often regarded computationally unfeasible for IoT devices. Therefore, this paper tries to push that limit by efficiently calculating pairing operation together with scalar multiplication and exponentiation over Barreto-Naehrig (BN) curve by applying the state of art techniques. In addition to the theoretic explanation of the applied techniques, the authors also show a high-level implementation using C programming on a raspberry pi model 3 B, instead of hardware specific implementation.

    DOI: 10.12720/jcm.13.2.88-93

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  • A study on the error performance of soft-decision decodings for binary linear codes on a 4-level quantization over an awgn channel Reviewed

    Takuya Kusaka

    IEICE Transactions on Fundamentals of Electronics, Communications and Computer Sciences   E100A ( 12 )   3016 - 3022   2017.12

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    In this paper, a study on the design and implementation of uniform 4-level quantizers for soft-decision decodings for binary linear codes is shown. Simulation results on quantized Viterbi decoding with a 4-level quantizer for the (64, 42, 8) Reed-Muller code show that the optimum stepsize, which is derived from the cutoff rate, gives an almost optimum error performance. In addition, the simulation results show that the case where the number ofoptimum codewordsislarger than the one fora received sequence causes non-negligible degradation on error performance at high SN ratios of Eb/N0.

    DOI: 10.1587/transfun.E100.A.3016

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  • Study on Reduction on Average Computational Complexity of GMD Decoding using Property of Bounded Distance Decoding Reviewed

    S. Ueda and T. Kusaka

    Proceedings of the 8th International Workshop on Advances in Networking and Computing   2017.11

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  • Solving 114-bit ECDLP for a Barreto-Naehrig Curve Reviewed

    T. Kusaka, S. Joichi, K. Ikuta, M. A. Khandaker, Y. Nogami, S. Uehara, N. Yamai and S. Duquesne

    Proceedings of the 20th Annual International Conference on Information Security and Cryptology   2017.11

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  • An Efficient Implementation of Trace Calculation over Finite Field for a Pseudorandom Sequence Reviewed

    Y. Hashimoto, M. A. Khandaker, Y. Kodra, T. Park, T. Kusaka, H. Kim and Y. Nogami,

    Proceedings of the Fifth International Symposium on Computing and Networking   2018-January   451 - 455   2017.11

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    Trace function is a well known index of finite field theory and practically, it is used for some security applications. However, present trace calculation with binary method is far from the practice on an IoT device. This paper considers an efficient trace calculation without vector multiplication by focusing on the matrix representation and the linearity of trace function. By using pre-computation, a trace calculation is executed by m times multiplication and the memory consumption is 4m bytes. This paper especially uses a pseudorandom generator called NTU sequence to show the efficiency because it has paid much attention as a random generator for security applications. When considering 128-bit length of periodic sequence with NTU sequence for security applications, parameters will be p = 7 and m = 50. From the experimental results, a trace calculation with them will be executed within 5[μs], and the memory consumption is 200 bytes which is 0:625% of the storage in Arduino Uno. Therefore, this work contributes to implementing an efficient trace calculation on an IoT device with low memory consumption.

    DOI: 10.1109/CANDAR.2017.86

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  • An ECC implementation with a twisted Montgomery curve over F_q^32 on an 8-bit microcontroller Reviewed

    Y. Hashimoto, M. A. Khandaker, Y. Kodra, T. Park, T. Kusaka, H. Kim and Y. Nogami,

    Proceedings of the Fifth International Symposium on Computing and Networking   445 - 450   2017.11

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  • Estimation of computational complexity of Pollard's rho method based attack for solving ECDLP over Barreto-Naehrig curves Reviewed

    K. Ikuta, T. Kusaka, M. A. Khandaker, Y. Nogami and T. Austin

    Proceedings of the 32nd International Technical Conference on Circuits/Systems, Computers and Communications   592 - 595   2017.7

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  • A Study on Soft-out of Soft-in/Soft-out Decoding Algorithms for Binary Linear Codes Reviewed

    S. Fujimoto, T. Kusaka and S. Ueda

    Proceedings of the International Symposium on Information Theory and Its Applications   305 - 309   2016.11

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  • Solving 94-Bit ECDLP with 70 Computers in Parallel Reviewed

    S. Miyoshi, Y. Nogami, T. Kusaka and N. Yamai,

    17th International Conference on Pairing-Based Cryptography   2 ( 8 )   1257 - 1257   2015.8

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  • Experimental evaluation of the efficiency of associative rational points for random walks on ECDLP

    Yuki Kono, Yasuyuki Nogami, Takuya Kusaka

    14th International Symposium on Communications and Information Technologies, ISCIT 2014   366 - 367   2015.1

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    Pollard's Rho method is well-known as a method for solving Elliptic Curve Discrete Logarithm Problem (ECDLP). It is based on an efficient random walk of rational points on elliptic curve. This research accelerates the random walk with associative rational points. Since associative rational points are generated with a small additional cost and thus the random walk becomes more efficient. In order to solve an ECDLP over Barreto-Naehrig curve, for an example, this paper applies associative rational points and then evaluates the efficiency by some experiments.

    DOI: 10.1109/ISCIT.2014.7011933

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  • Introduction of a Recursive Method for Specific Weight Binary Vector Generation in Decreasing Order of its Reliability Measure Reviewed

    Proceedings of the International Symposium on Information Theory and Its Applications   534 - 583   2014.10

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  • A Max-Log-MAP Decoding Using a Recursive Vector Generator for Binary Linear Codes

    T.Kusaka

    Technical Report of IEICE, The Institute of Electronics, Information and Communication Engineers   IT2013-66   77 - 80   2014.3

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  • A Soft-Decision Sphere Decoding Based on a Recursive Vector Generator Using Euclidian Distance

    KUSAKA Takuya, FUJIWARA Toru, YOKOYAMA Ryuhei

    IEICE technical report. Information theory   IT2013-33 ( 228 )   7 - 11   2013.9

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    A soft-decision sphere decoding algorithm for general binary linear codes is proposed. The algorithm is based on a modified recursive vector generator previously proposed by the authors. The algorithm can be applied for codes that do not have special structures. Simulation results of the algorithm for codes of length up to 128 show the algorithm's effectiveness.

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  • PeerCastにおけるデータロスのない動的な自律分散型経路変更機能の設計と実装 Reviewed

    安原 健介, *日下 卓也

    電子情報通信学会論文誌(D)   Vol.J92-D ( No.9 )   1 - 5   2009.9

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  • Method for Generating a Competing Codeword Using a Chain of Minimum Distance Searches Reviewed

    J. Asatani, *T. Koumoto, T. Fujiwara and T. Kasami

    Proceedings of the International Symposium on Information Theory and Its Applications   260 - 264   2006.10

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  • Soft-input soft-output decoding algorithm of linear block codes based on minimum distance search

    J Asatani, T Koumoto, T Fujiwara, T Kasami

    2004 IEEE INTERNATIONAL SYMPOSIUM ON INFORMATION THEORY, PROCEEDINGS   345   345 - 345   2004

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    A new soft-input soft-output (SISO) decoding algorithm based on minimum distance search (MDS), called SISO-IMDS, is presented. The bit error rate of the proposed SISO decoding algorithm is almost the same as those of Max-Log-MAP and Log-MAP algorithms. Moreover, the average decoding complexity of the MDS based SISO decoding algorithm is much smaller than those of trellis-based SISO decoding algorithms. Consequently, the proposed SISO-IMDS can be applied in practical iterative decoding algorithms for a product code and a block turbo code.

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  • An improvement to GMD-like decoding algorithms

    Hitoshi Tokushige, Takuya Koumoto, Tadao Kasami

    IEEE International Symposium on Information Theory - Proceedings   396   2000

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    For binary linear block codes, we introduce "multiple GMD decoding algorithm", where GMD-like decoding is iterated around a few appropriately selected search centers. Compared with the original GMD decoding by Forney [1], this decoding algorithm provides better error performance with increasing the number of iterations of erasure and error correction moderately. To reduce the number of iterations, we derive new effective sufficient conditions on the optimality of decoded codewords.

    DOI: 10.1109/ISIT.2000.866694

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  • A Consideration of Side-Channel Attacks on Curve25519 using Order 4 Rational Points

    ( 2019 )   69 - 74   2019.8

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  • The Weight Distributions of the (256,k) Extended Binary Primitive BCH Codes with k = 71, 187, 191, and 199 (情報理論)

    藤原 融, 日下 卓也

    電子情報通信学会技術研究報告 = IEICE technical report : 信学技報   119 ( 47 )   23 - 28   2019.5

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  • Analyzing Final Round Key of AES Implemented on Microcomputer using Neural Network

    小杉聡志, 城市翔, 生田健, 日下卓也, 野上保之, 高橋規一

    電子情報通信学会技術研究報告   118 ( 478(ISEC2018 81-134) )   2019

  • 線形複雑度が可変なある擬似乱数系列の部分的乱数性に対する評価

    武田祐樹, 小寺雄太, 日下卓也, 野上保之

    情報理論とその応用シンポジウム予稿集(CD-ROM)   41st   2018

  • Study on Soft-out of SISO Decodings for Binary Linear Codes

    FUJIMOTO Shohei, KUSAKA Takuya

    IEICE technical report. Information theory   114 ( 438 )   35 - 39   2015.1

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    Research on SISO decodings for binary linear codes are widely available. In the SISO decodings, a set of codewords, called competing codewords, are used to calculate a soft-out sequence. However, well known formula of the soft-out value of a symbol position of the soft-out sequence might include duplicate operations in the decoding algorithms. In this research, study and analysis for the formula are given.

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  • Design and Implementation of Dynamic Autonomous Distributed Connection Switching Function without Data Loss in PeerCast

    YASUHARA Kensuke, KUSAKA Takuya

    The IEICE transactions on information and systems   92 ( 9 )   1677 - 1681   2009.9

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  • Performance Evaluation and Analysis on Digital Watermark for Still Images with JPEG Compression Attack

    MASUNO Tetsushi, KUSAKA Takuya, FUJIWARA Toru

    IEICE technical report   109 ( 143 )   49 - 54   2009.7

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    Digital watermark is a useful technology for copyright protection. A number of studies on embedding watermark into spatial-domain or frequency-domain of still image are known. Recently, there are studies on applying error control coding to digital watermark to improve strength of protection of digital watermark. There are also study on JPEG compression as a way to attack to the watermark. Then, there should be a problem on evaluation of digital watermark system because number and range for parameters of watermark methods are large enough to prevent exhaustive research. Reproducibility on performance evaluation for schemes are also problem. In this study, Reed-Muller code is chosen for error controlling on digital watermark system because its controllability of Hamming weight, especially minimum weight. We also propose a digital watermark scheme which emphasized repeatability by implement a software that modeled JPEG compression process with a standard algorithm. Experimental results and analysis are shown for application of error control coding to digital watermark.

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  • Study on extension of reliable multicast middleware

    KATO Nobuaki, SUNANO Yoshimi, KUSAKA Takuya

    IEICE technical report   108 ( 359 )   7 - 12   2008.12

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    Multicast technology is well known and widely used as efficient information delivery system. The authors are working on improvement on a reliable multicast system for application of education support purpose. It consists of Reliable Multicast Middleware (RMM) as kernel of the system and application parts such that electric whiteboard system. RMM uses both IP multicast and IP unicast to form hybrid reliable multicast system. In this research, design and implementation of extension of RMM as individual information delivery function based on TCP and secure communication function based on authentication and cryptography. Design and implementation of sound delivery system as an example of real time stream application and screen snapshot delivery system as an example of real time and non-streaming application are also shown.

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  • Design and implementation of dynamic autonomous distributed connection switching function in PeerCast

    YASUHARA Kensuke, KOUMOTO Takuya

    IEICE technical report   108 ( 258 )   7 - 12   2008.10

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    Multicast communication is used for multimedia contents services with small impact on both network traffic and server load. Recently, demand on application level multicast (ALM) is increasing because it is easy to manage and control whole multicast system by its users. We are focusing on PeerCast which is an implementation of ALM for multimedia streaming. PeerCast is useful enough for basic streaming applications, but its algorithm of construction of routing tree is not nice and PeerCast isn't capable to switch routing dynamically without loss of data. We are working on improvement on PeerCast to design and implement a function on dynamic autonomous distributed connection switching on multicast routing. We already presented basic part of our work in last year. In this research, extensions and improvements for proposed method and its results are shown.

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  • Design and Implementation of the reliable multicast delivery for middleware of electronic WhiteBoard system

    KATO Nobuaki, SUNANO Yoshimi, KOUMOTO Takuya

    IEICE technical report   108 ( 134 )   61 - 66   2008.7

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    To support of education, an electronic whiteboard of JSDT is used on department of communication network engineering of Okayama University. Middleware of the system uses IP multicast, and resending-function of the middleware offers reliability. Since the middleware consumes resources of computer and network heavily, efficient implementation of new middleware is required. At first, we removed functions of the middleware which were not used by the electronic whiteboard application. We also designed a new protocol to reduce network traffic. Implementation and analysis on performance of the new middleware are shown.

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  • Soft-Decision Decoding for Linear Codes : The Quest to Maximum Likelihood Decoding

    KOUMOTO Takuya

    IEICE technical report   107 ( 354 )   27 - 32   2007.11

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    Recent researches on Turbo coding and LDPC with iterative soft-decision decoding achieve almost the Shannon limit. It is also known that the analysis on structure of useful LDPCs is not easy and to perform maximum likelihood decoding for these codes is not also easy. In this paper, we show the results on research of maximum likelihood decoding and sub optimum decoding algorithms which includes recursive algorithms.

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  • An implementation of a connection switching function for dynamic routing in PeerCast

    YASUHARA Kensuke, KOUMOTO Takuya, FUNABIKI Nobuo, SUGIYAMA Yuji

    IEICE technical report   107 ( 36 )   27 - 32   2007.5

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    Multicast has been used by multimedia applications, such that video on demand and streaming systems, for reducing network traffic and load of contents servers. Recently, application level multicast(ALM) becomes a better solution for this, purpose compared with IP multicast due to user side controllability and adaptability. PeerCast is a well known implementation of a stream oriented ALM system. However the current version of PeerCast has drawbacks on optimality of the routing algorithm which causes large average transmission delay. In this research we introduce a method on the connection switching function for dynamic routing without loss of data for PeerCast. A preliminarily implementation and results of evaluation on reduction on transmission delay is also shown.

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  • Experimental Evaluations of Network Load Dispersion Effects by VNC Proxy

    MATSUMOTO Kohei, KAGOTANI Hiroto, KOUMOTO Takuya, FUNABIKI Nobuo

    IEICE technical report   106 ( 355 )   51 - 54   2006.11

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    The Virtual Network Computing (VNC) has problems such as network load increase and access control for practical use in multi-client environment. We develop a VNC Proxy to solve those problems. In this paper, we evaluate load dispersion performance of the VNC Proxy through experimental results. We arrange proxies in consideration of the network toporogy and measure the network load and delay in the experiment. As a result, network load were dispersed by the VNC Proxy without critical delay.

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  • A development of a software which provides high mobility to Windows programs with API Hook

    SAITOH Masataka, KOUMOTO Takuya, SUGIYAMA Yuji

    IEICE technical report   106 ( 327 )   25 - 30   2006.10

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    Recently, we can use more than two Windows computers for a personal use in several places. But it is not easy to apply same environment at each computer. We aim to leverage a portable media device as an application platform without any special hardwares, any modifications of source code and any administrative priviledges. Then it allows to use the same environment at any computers. In this paper, we analyze behaviors of applications, and we make a software provides high mobility to Windows programs through the use of API Hook. Then we demonstrate the effectiveness of the software applying some applications.

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  • Research on Making of Electronic Whiteboard Secure

    YASUKAWA Yukihiro, KOUMOTO Takuya, FUNABIKI Nobuo, SUGIYAMA Yuji

    IEICE technical report   106 ( 263 )   7 - 12   2006.9

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    It is not easy to see the screen from the back seat at conference with commodious room. To solve this problem, an electronic whiteboard system using the IP multicast communication can be used, but an existing system has the problem concerning security. In this research, an existing whiteboard system is made secure and extended to a practicable whiteboard. The whiteboard system is introduced into an actual conference, and effectiveness is shown by the questionnaire from users.

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  • Structural Analysis of Minimum Weight Codewords of the Extended (32, 21, 6) and (64, 45, 8) BCH Codes Using Invariance Property

    ASATANI Jun, KOUMOTO Takuya, FUJIWARA Toru, KASAMI Tadao

    IEICE technical report   106 ( 58 )   25 - 30   2006.5

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    In this report, two typical examples (32,21,6) and (64,45,8) extended BCH codes are considered, and their structures of the set of minimum weight codewords are analyzed in terms of Boolean polynomial representation.

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  • A Proposal of Proxy for Load Dispersion and Access Control in VNC System

    MATSUMOTO Kohei, KAGOTANI Hiroto, KOUMOTO Takuya, FUNABIKI Nobuo

    IEICE technical report   106 ( 41 )   57 - 60   2006.5

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    The Virtual Network Computing (VNC) is a useful network application to let a user operate the desktop display of a remote PC on his/her local PC. However, VNC has two problems for practical use in multi-client environment. One is the increase of network loads when a number of clients are connecting to a VNC server. Another is the lack of capability of the access control of each user by the administrator of the VNC server. The more clients connect VNC server, the more serious these problems become. In this paper, we present a VNC proxy to solve these problems, where it reduces the network loads by dispersing the roles of the server into multiple mirrors, and enables the VNC administrator to control the access right by each client.

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  • A Development of PeerCast-Based Multimedia Disribution System PeerStream and Its Evaluations

    SAITOH Masataka, ISOGAI Megumi, KOUMOTO Takuya, FUNABIKI Nobuo

    IEICE technical report   105 ( 562 )   5 - 8   2006.1

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    Recently, demands for multimedia applications such as video conferences, remote lectures, and video-on-demands have been increased due to wide spreads of broadband networks. In this paper, we present the design and the implementation of the PeerCast-based multimedia distribution system called PeerStream. PeerCast is a multimedia distribution platform with open sources using the peer-to-peer technology. Through experiments of the system in our school LAN, we show that the delay at a client from the server is approximately proportional to the number of relaying hosts. We will use the results in our studies of optimal routing algorithms.

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  • The structure of the set of minimum weight codewords of the extended (32,21,6) and (64,45,8) BCH codes

    ASATANI Jun, KOUMOTO Takuya, FUJIWARA Toru, KASAMI Tadao

    28 ( 2 )   439 - 442   2005.11

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  • Study of Making Highly Effictive Perspective Transform Apllies the Technology of Video Compressing

    SHIMIZU Yasuhiro, KOUMOTO Takuya, OZAKI Ryo, SUGIYAMA Yuji, OKAMOTO Takuji

    IEICE technical report. Speech   105 ( 296 )   13 - 18   2005.9

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    Recently, demand for a personal small monitoring camera is increasing with evolution of the Internet. Though, we have a few choices for camera system which can take a wide-view video images for the purpose, a variety of low-priced CMOS or CCD sensor and DSP is available. Then, it is possible to develop a wide-view video synthesis system by using two or more CMOS or CCD sensors and DSP chips. In this report, we propose a method to generate a perspective transformed image to synthesize the wide-view image by applying the technology which is based on video image compression for decreasing an average computational complexity. Examples and numerical results are shown.

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  • A proposal of a panoramic image synthesizing algorithm using an optimization method

    ISOGAI Megumi, FUNABIKI Nobuo, KOUMOTO Takuya, SUGIYAMA Yuji, OZAKI Ryo, OKAMOTO Takuji

    104 ( 512 )   17 - 24   2004.12

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    Recently, a panoramic image has been expected in applications to various monitoring systems and virtual space presentation systems due to the advantage of expressing a wide range of scenes by one image. In this paper, we propose a panoramic image synthesizing algorithm for a panoramic image generating system to monitor indoor scenes, which is composed of,one personal computer and three inexpensive cameras set in row. This system has been studied in our group with the view of applications to home/store monitoring and safety confirmation of seniors living alone. The proposed algorithm consists of the approximate calibration stage and the detailed calibration stage, to fit images from side cameras to the image of the central camera as best as possible. The first stage transforms the coordinates of the side image to resolve the difference caused by view directions and locations of cameras, where the parameters are calculated using the limited number of feature points in overlapped regions of two images. The second stage applies both the coordinate transformation and the color correction with the parameters calculated using every pixel in overlapped regions. In both stages, parameters are searched by a local search method that is a typical optimization method. Through experiments with a variety of still images taken in our office, we show the effectiveness of our proposed algorithm.

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  • Soft-Input Soft-Output Decoding Algorithm Using a Structure of the Set of Minimum Weight Codewords of Reed-Muller Codes with Simulation Results

    ASATANI Jun, KOUMOTO Takuya, FUJIWARA Toru, KASAMI Tadao

    IEICE technical report. WBS, Wideband System   103 ( 715 )   115 - 120   2004.3

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    The authors have proposed soft-input/soft-output (SISO) decoding algorithm based on minimum distance search (MDS). The soft-outputs are calculated from a list of codewords which are generated by a local search for sub-codewords at minimurn Hamming distance from t,he most likely codeword. In this report, we devised a new MDS using a structure of the set of minimum weight codewords of Reed-Muller codes. By simulation, the average decoding complexity of the MDS based SISO decoding algorithm is much smaller than those of trellis-based SISO decoding algorithms.

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  • Soft-Input Soft-Output Decoding Algorithm Using a Structure of the Set of Minimum Weight Codewords of Reed-Muller Codes with Simulation Results

    ASATANI Jun, KOUMOTO Takuya, FUJIWARA Toru, KASAMI Tadao

    IEICE technical report. Information theory   103 ( 711 )   115 - 120   2004.3

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    The authors have proposed soft-input/soft-output (SISO) decoding algorithm based on minimum distance search (MDS). The soft-outputs are calculated from a list of codewords which are generated by a local search for sub-codewords at minimurn Hamming distance from t,he most likely codeword. In this report, we devised a new MDS using a structure of the set of minimum weight codewords of Reed-Muller codes. By simulation, the average decoding complexity of the MDS based SISO decoding algorithm is much smaller than those of trellis-based SISO decoding algorithms.

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  • Soft-Input Soft-Output Decoding Algorithm Using a Structure of the Set of Minimum Weight Codewords of Reed-Muller Codes with Simulation Results

    ASATANI Jun, KOUMOTO Takuya, FUJIWARA Toru, KASAMI Tadao

    Technical report of IEICE. ISEC   103 ( 713 )   115 - 120   2004.3

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    The authors have proposed soft-input/soft-output (SISO) decoding algorithm based on minimum distance search (MDS). The soft-outputs are calculated from a list of codewords which are generated by a local search for sub-codewords at minimurn Hamming distance from t,he most likely codeword. In this report, we devised a new MDS using a structure of the set of minimum weight codewords of Reed-Muller codes. By simulation, the average decoding complexity of the MDS based SISO decoding algorithm is much smaller than those of trellis-based SISO decoding algorithms.

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  • Soft-Input Soft-Output Decoding Algorithm Based on Iterative Minimum Distance Search for Reed-Muller Codes

    ASATANI Jun, KOUMOTO Takuya, FUJIWARA Toru, KASAMI Tadao

    Proc. the 26th Symposium on Information Theory and Its Applications, Higashiura, Hyogo, Japan, Dec. 2003   26 ( 1 )   1 - 4   2003.12

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  • Adaptive Recursive Maximum Likelihood Decoding Based on the Coarsest Parallel Concatenation Decomposition : Evaluation of the Decoding Complexity by Simulation

    KOUMOTO Takuya, KAJI Yuichi, FUJIWARA Toru, KASAMI Tadao

    26 ( 1 )   5 - 8   2003.12

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  • Implementation and Simulation Results of Adaptive Recursive Maximum Likelihood Decoding

    KOUMOTO Takuya, KAJI Yuichi, FUJIWARA Toru, KASAMI Tadao

    IEICE technical report. Information theory   103 ( 215 )   29 - 32   2003.7

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    We have proposed a new adaptive recursive maximum likelihood decoding for binary linear block code with significant reduction on computational complexity on average. The basic properties of the algorithm have been shown in another technical report. In this report, we show the useful information to implement the algorithm for the (128, 64, 16) RM code. Simulation results are also shown.

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  • Adaptive recursive maximum likelihood decoding based on parallel concatenation decomposition

    KASAMI Tadao, FUJIWARA Toru, KAJI Yuichi, KOUMOTO Takuya

    Technical report of IEICE. SST   102 ( 745 )   109 - 114   2003.3

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    Adaptive recursive MLD algorithm based on the coarsest parallel concatenation decomposition for binary linear codes is introduced.

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  • Adaptive recursive maximum likelihood decoding based on parallel concatenation decomposition

    KASAMI Tadao, FUJIWARA Toru, KAJI Yuich, KOUMOTO Takuya

    102 ( 747 )   109 - 114   2003.3

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    Adaptive recursive MLD algorithm based on the coarsest parallel concatenation decomposition for binary linear codes is introduced.

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  • Adaptive recursive maximum likelihood decoding based on parallel concatenation decomposition

    KASAMI Tadao, FUJIWARA Toru, KAJI Yuich, KOUMOTO Takuya

    IEICE technical report. Information theory   102 ( 741 )   109 - 114   2003.3

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    Adaptive recursive MLD algorithm based on the coarsest parallel concatenation decomposition for binary linear codes is introduced.

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  • Adaptive recursive maximum likelihood decoding based on parallel concatenation decomposition

    KASAMI Tadao, FUJIWARA Toru, KAJI Yuich, KOUMOTO Takuya

    Technical report of IEICE. ISEC   102 ( 743 )   109 - 114   2003.3

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    Adaptive recursive MLD algorithm based on the coarsest parallel concatenation decomposition for binary linear codes is introduced.

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  • Reduced Complexity Iterative Decoding Using a Sub-optimum Minimum Distance Search

    ASATANI Jun, KOUMOTO Takuya, TOMITA Kenichi, KASAMI Tadao

    Technical report of IEICE. ISEC   102 ( 743 )   115 - 117   2003.3

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    In this report, we propose (1) a new sub-optimum minimum distance search (sub-MDS), whose search complexity is reduced considerably compared with optimum MDSs and (2) a termination criterion, called near optimality condition, to reduce the average number of decoding iterations with little degradation of error performance for the proposed decoding using sub-MDS iteratively. Consequently, the decoding algorithm can be applied to longer codes with feasible complexity. Simulation results for several Reed-Muller (RM) codes of lengths 256 and 512 are given.

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  • Top-down Recursive Maximum Liklihood Decoding Using Ordered Statistic Information for Half Rate Codes

    KOUMOTO Takuya, KASAMI Tadao

    IEICE technical report. Information theory   102 ( 331 )   13 - 18   2002.9

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    To evaluate optimal error performances on half-rate binary linear codes of length 128 or larger is not easy. In this paper, a new top-down style recursive maximum likelihood decoding using ordered statistic information is proposed. Simulation results on error performance and computational complexity are shown for the half-rate RM code, the extended QR code and the extended BCH code of length 128.

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  • Top-down Recursive Maximum Liklihood Decoding Using Ordered Statistic Information

    KOUMOTO Takuya, KASAMI Tadao

    Technical report of IEICE. SST   101 ( 730 )   7 - 10   2002.3

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    To achieve optimal error performance on half rate binary linear codes of length 128 or larger is not easy. In this research, a new top-down style recursive maximum likelihood decoding using ordered statistic information is proposed. Simulation results on error performance and computational complexity are shown.

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  • A Soft-Decision Iterative Decoding Algorithm Using a Top-Down and Recursive Minimum Distance Search

    Asatani Jun, Tomita Kenichi, Koumoto Takuya, Takata Toyoo, Kasami Tadao

    Technical report of IEICE. SST   101 ( 730 )   17 - 22   2002.3

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    In this paper, we present a new soft-decision iterative decoding algorithm using an efficient minimum distance search (MDS) algorithm. The proposed MDS algorithm is a top-down and recursive MDS algorithm, which finds a most likely codeword among the codewords at the minimum distance of the code from a given codeword. A search is made in each divided section by a call by need" from the upper section. As a consequence, the search space and computational complexity are reduced significantly. The simulation results show that the proposed decoding algorithm achieves near error performance to the maximum likelihood decoding for any RM code of length 128 and suboptimal for the (256, 37), (256, 93) and (256, 163) RM codes.

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  • On Selection of Search Centers of Iterative Bounded-distance Decoding Algorithm

    Tokushige H., Nakamaye K., Koumoto T., Kasami T.

    Technical report of IEICE. SST   100 ( 693 )   85 - 90   2001.3

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    We consider iterative soft-decision decoding algorithms in which bounded distance decodings are carried out with respect to successively chosen input words, called search centers. Their error performances are degraded by the decoding failure of bounded distance decoding and the duplication in generating candidate codewords. To avoid those weak points, we present a new method of selecting sequences of search centers. For some BCH codes, we show the effectiveness by simulation results.

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  • A New Iterative Soft-Decision Decoding Algorithm Using List Decoding of Minimum Weight Sub-trellis Search

    Asatani Jun, Tomita Kenichi, Koumoto Takuya, Takata Toyoo, Kasami Tadao

    Technical report of IEICE. SST   100 ( 693 )   9 - 16   2001.3

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    Iterative decoding algorithm using minimum weight sub-trellis search, which is one of minimum distance search (MDS), has been proposed by Koumoto et al. Their decoding algorithm achieve not only almost optimum error performance with for all Reed-Muller(RM) codes and extended BCH(EBCH) codes of length 64 but also near optimum for the (128, 29) and the (128, 36) EBCH code with a drastic reduction of decoding complexity. In this paper, We present a new iterative soft-decision decoding algorithm using efficient MDS algorithm. In the proposed decoding algorithm, to make improvement of error performance, we devise two methods, (1) which improve the quality of initial candidate codewords and (2) in the case previously generated codewords appear twice in iterative decoding, instead of finishing decoding, continue decoding by using list decoding of MDS. The simulation results show that the proposed decoding algorithm achieves near error performance with MLD for any RM codes of length 128 and practically optimum for the (256, 37), (256, 93) and (256, 163) RM codes.

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  • Condition for Reducing the Number of Iterations of Iterative Decoding

    KOUMOTO Takuya, TAKATA Toyoo, KASAMI Tadao, LIN Shu

    IEICE technical report. Information theory   95 ( 591 )   25 - 30   1996.3

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    In this paper, sufficient conditions on the optimality of a candidate codeword are investigated based on: (1)partial or complete knowledge of the weight (or distance) profile of a code and (2) for a given positive integer h, h or fewer already generated candidate codewords. These conditions are less stringent than the previous conditions A condition is also derived to rule out some useless test error patterns in the process of generating candidate codewords. The average reduction of number of decoding iterations is evaluated for RM codes over the AWGN channel using BPSK signalling by simulation.

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Research Projects

  • Construction of a medical information secure management system using ICT and encryption technology

    Grant number:20K20484  2019.06 - 2023.03

    Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research Grant-in-Aid for Challenging Research (Pioneering)  Grant-in-Aid for Challenging Research (Pioneering)

    野上 保之, 日下 卓也, 福島 行信, 横平 徳美, 山内 利宏

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    Grant amount:\25350000 ( Direct expense: \19500000 、 Indirect expense:\5850000 )

    効率のよい秘密鍵暗号実装のための乱数生成法の提案,ブロック暗号ベースの検索可能暗号の実装について研究を進めた.ペアリング暗号を活用した公開鍵暗号ベースの検索可能暗号の実装,個人情報保護のための可変長セキュリティ公開鍵暗号について着手した.データベース・秘密分散について,TCPインキャストの対策研究を行った.メールシステムについて,本研究で開発する拡散暗号法をプロトコルスタック内のどのプロトコルレイヤに対して適用することが望ましいかを検討した.その結果,メールの送信者から受信者までのエンドツーエンドでの暗号化通信を可能とするPGPやS/MIMEに対して拡散暗号法を適用するのが最も望ましいとの結論に至った.このようにエンドツーエンドでの暗号化通信を担うプロトコルレイヤに対して拡散暗号法を適用することにより,拡散暗号法を利用できるユーザは送信者と受信者のみに限定されるものの,その一方で,送信者から受信者までの通信路上のすべての通信区間および中継ホスト(メールサーバ)において,メールが拡散暗号法により暗号化された状態を保つことが可能となる.メールシステムで,メールサーバを運用するサーバ計算機のセキュリティを向上させるために,Linuxにおいて標準で採用されているSELinuxに着目し,SELinuxのセキュリティポリシを細粒度に削減する手法を提案し,その実現方式を示した.この手法によって,SELinuxで標準で配布しているセキュリティポリシから不要なポリシ記述を削減でき,メールサーバで必要となる操作のみを許可するセキュリティポリシを生成できる.これにより,メールサーバプログラムや他のプログラムに脆弱性があったとしても,必要最小限の操作しか許可されず,被害を抑制することが期待できる.また,仮想計算機モニタを利用して,ゲストOSでのプログラム実行の証拠を保
    全するシステムの検討を行った.

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  • Realization of secure and reliable communication in a remote control type / autonomous mobile system in the IoT era

    Grant number:16H01723  2016.04 - 2019.03

    Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (A)  Grant-in-Aid for Scientific Research (A)

    Nogami Yasuyuki

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    Grant amount:\39390000 ( Direct expense: \30300000 、 Indirect expense:\9090000 )

    In this research, using a specific drive system such as an electric vehicle and robot capable of autonomous driving and remote control, the advanced security technology (data authentication, device authentication, secure key update) we have clarified the security level that is realized without any problems by verifying how much the real-time performance is affected. Specifically, for the CAN system, data authentication with message authentication code that is generated by AES, random number generator, and lightweight encryption has been implemented. Then, side-channel attack has been demonstrated experimentally, key update function as the countermeasure using elliptic pairing-based cryptography has been also implemented. Their real-time processing could be realized.

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  • Study on digital watermark without detection error using soft-decision decoding for linear codes

    Grant number:26330157  2014.04 - 2017.03

    Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (C)  Grant-in-Aid for Scientific Research (C)

    Kusaka Takuya

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    Grant amount:\4680000 ( Direct expense: \3600000 、 Indirect expense:\1080000 )

    A method which uses a set of the minimum weight codewords of Reed-Muller codes and extended BCH codes as an embedded information for digital watermark system is proposed. By using cases of decoding failure of decoding algorithms, the probability of erroneous detection can be reduced. The effectiveness of the proposed method is assured by computer simulations.
    In addition, effects of quantization errors in the floating number operations in soft-in/soft-out decoding algorithms is evaluated by simulations. The simulation results show that effects are negligible for the digital watermarks. By using the proposed methods, the digital watermark systems which have small erroneous detection probability can be implemented.

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  • Security Evaluation for Elliptic Curve Pairing-based Cryptography with Conjugate Rational Points by Distributed and Parallelized Experiments

    Grant number:25280047  2013.04 - 2016.03

    Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (B)  Grant-in-Aid for Scientific Research (B)

    Nogami Yasuyuki, Uehara Satoshi, Kusaka Takuya, Yamai Nariyoshi

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    Grant amount:\14170000 ( Direct expense: \10900000 、 Indirect expense:\3270000 )

    In order to evaluate the security of elliptic curve pairing-based cryptography, this research has considered several attacking method, particularly rho method with some improvements and experiments. In detail, this research discussed a random number generator for efficiently carrying out random walks of rational points and then discussed an efficient distributed parallel attacks. Then, this paper also developed some efficient arithmetic operations on elliptic curve and evaluated some other approaches that kept all of generated random rational points for the attack in contrast to rho method. As a result, this research could show that 88 bit pairing-based cryptography could be broken with about three hours computation by 4 PCs. This research still keeps on attacking 114 bit pairing-based cryptography.

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  • 2元線形ブロック符号のトップダウン型再帰的最尤及び準最尤復号法に関する研究

    2002 - 2004

    科学研究費補助金 

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    Grant type:Competitive

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  • Study on Top-down Recursive MLD and Suboptimum decoding for Binary Liniear Block Codes

    2002 - 2004

    Grant-in-Aid for Scientific Research 

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    Grant type:Competitive

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  • Study on Linear Block Code

    1994 - 2005

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    Grant type:Competitive

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  • 線形ブロック符号に関する研究

    1994 - 2005

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    Grant type:Competitive

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  • Implementation on decoder

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    Grant type:Competitive

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  • 復号器の実装に関する研究

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    Grant type:Competitive

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  • Computer Mathematics (2021academic year) Second semester  - 月7,月8,木1,木2

  • Algebra (2021academic year) Second semester  - 月7,月8,木1,木2

  • Seminar in Information Security (2021academic year) Year-round  - その他

  • Information Theory (2021academic year) Fourth semester  - 火1,火2,金1,金2

  • Special Lectures (2021academic year) special  - その他

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  • Special Lectures I (2021academic year) special  - その他

  • Error Control Coding (2021academic year) Late  - 水1,水2

  • Specific Research of Electronics and Information Systems Engineering (2021academic year) Year-round  - その他

  • High Reliable Communication (2021academic year) Late  - その他

  • Computer Mathematics (2020academic year) Second semester  - 月7,月8,木1,木2

  • Algebra (2020academic year) Second semester  - 月7,月8,木1,木2

  • Seminar in Information Security (2020academic year) Year-round  - その他

  • Information Theory (2020academic year) Fourth semester  - 火1,火2,金1,金2

  • Special Lectures (2020academic year) special  - その他

  • Special Lectures II (2020academic year) special  - その他

  • Special Lectures I (2020academic year) special  - その他

  • Error Control Coding (2020academic year) Late  - 水1,水2

  • Specific Research of Electronics and Information Systems Engineering (2020academic year) Year-round  - その他

  • High Reliable Communication (2020academic year) Late  - その他

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