Authorship：Last author,　Corresponding author   Language：English   Publishing type：Research paper (international conference proceedings)  

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Authorship：Last author,　Corresponding author   Language：English   Publishing type：Research paper (international conference proceedings)  

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：MDPI AG  

Ensuring the reliability of data gathering from every connected device is an essential issue for promoting the advancement of the next paradigm shift, i.e., Industry 4.0. Blockchain technology is becoming recognized as an advanced tool. However, data collaboration using blockchain has not progressed sufficiently among companies in the industrial supply chain (SC) that handle sensitive data, such as those related to product quality, etc. There are two reasons why data utilization is not sufficiently advanced in the industrial SC. The first is that manufacturing information is top secret. Blockchain mechanisms, such as Bitcoin, which uses PKI, require plaintext to be shared between companies to verify the identity of the company that sent the data. Another is that the merits of data collaboration between companies have not been materialized. To solve these problems, this paper proposes a business-to-business collaboration system using homomorphic encryption and blockchain techniques. Using the proposed system, each company can exchange encrypted confidential information and utilize the data for its own business. In a trial, an equipment manufacturer was able to identify the quality change caused by a decrease in equipment performance as a cryptographic value from blockchain and to identify the change one month earlier without knowing the quality value.

DOI： 10.3390/s22134909

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Authorship：Lead author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.3390/e24060780

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Authorship：Lead author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.3390/e24060780

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

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

DOI： 10.1109/CANDARW53999.2021.00075

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Other Link： https://dblp.uni-trier.de/db/conf/ic-nc/candar2021w.html#EnamiKKN21

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

DOI： 10.1109/CANDAR53791.2021.00014

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Other Link： https://dblp.uni-trier.de/db/conf/ic-nc/candar2021.html#NanjoSKKN21

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

DOI： 10.1109/CANDARW53999.2021.00064

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Other Link： https://dblp.uni-trier.de/db/conf/ic-nc/candar2021w.html#NakanoseKKN21

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

DOI： 10.3390/e23091168

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

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

Authorship：Corresponding author   Language：English   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

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

DOI： 10.1109/ICCE-TW52618.2021.9603017

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Other Link： https://dblp.uni-trier.de/db/conf/icce-tw/icce-tw2021.html#NasuKN21

Authorship：Corresponding author   Language：English   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

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

CiNii Article

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

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

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

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

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

DOI： 10.1109/CANDAR53791.2021.00028

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Other Link： https://dblp.uni-trier.de/db/conf/ic-nc/candar2021.html#NanjoSKKN21a

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

DOI： 10.1007/978-3-030-72725-3_3

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Other Link： https://dblp.uni-trier.de/db/conf/svcc/svcc2020.html#TaketaKKN20

Authorship：Lead author   Language：English   Publishing type：Part of collection (book)   Publisher：De Gruyter  

DOI： 10.1515/9783110621730-006

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Other Link： https://www.degruyter.com/document/doi/10.1515/9783110621730-006/xml

Authorship：Lead author   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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Authorship：Lead author   Language：English   Publishing type：Part of collection (book)   Publisher：Springer International Publishing  

DOI： 10.1007/978-3-030-58208-1_2

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

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Other Link： https://dblp.uni-trier.de/db/journals/ijnc/ijnc10.html#YoshimotoUKKN20

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

Controller Area Network (CAN) is widely employed as an in-vehicle network, and is required for extremely high reliability. CAN uses five mechanisms to detect errors caused by channel noises in CAN frames. However, an adversary can reportedly falsify a CAN frame by tampering with sample points in the frame. In this paper, the effectiveness of a new falsification method that does not require sample point tampering is proposed. In the method, transient electromagnetic pulses are injected into a CAN bus by magnetic coupling that enables falsification at the target CAN node without error detection. The proposed method was examined on a CAN bus which consists of two CAN nodes. As a result, the new falsification method was effective for CAN.

Web of Science

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Authorship：Lead author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：Institute of Electronics, Information and Communications Engineers (IEICE)  

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

DOI： 10.1109/candar.2019.00040

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

Machine learning (ML) technology has been getting popular in many applications where ML purposes to analyze or classify data, or predicting the phenomenon follows from the previous conditions, for example. However, the spread of ML technologies allows an attacker to use them into the attack for the sake of sniffing secret information. Since the randomness has been used for an inseparable part of the cryptographic applications to ensure the security, the resistance of a random sequence against analysis based on the ML technologies have to be required. The authors anticipate having the mutual relationship between the classical properties of the randomness, linear complexity (LC) in particular, and the structure of a neural network (NN), which is a class of ML. In this research, the authors find that the strength of each connection between nodes in the NN is relevant to the linear recurrence relation of the target sequence by observing parameters after complete learning. In other words, the difficulty of predicting the next bits from a given sequence would be discussed based on the LC of a sequence in most cases. The experimental results are introduced to clarify the black box in this research.

DOI： 10.1109/candarw.2019.00074

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

DOI： 10.1109/candar.2019.00027

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

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

DOI： 10.1109/candarw.2019.00080

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

DOI： 10.15803/ijnc.9.2_171

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Authorship：Lead author   Language：English   Publishing type：Part of collection (book)   Publisher：Springer International Publishing  

DOI： 10.1007/978-3-030-17982-3_19

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Scientific Research Publishing, Inc.  

DOI： 10.4236/jis.2019.103008

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：ASTES Journal  

The authors propose a well balanced multi-value sequence (including a binary sequence). All the sequence coefficients (except the zero) appear almost the same in number, thus, the proposed sequence is so called the well balanced sequence. This paper experimentally describes some prominent features regarding a sequence, for instance, its period, autocorrelation, and cross-correlation. The value of the autocorrelation and cross-correlation can be explicitly given by the authors formulated theorems. In addition, to ensure the usability of the proposed multi-value sequence, the authors introduce its flexibility by making it a binary sequence. Furthermore, this paper also introduces a comparison in terms of the linear complexity and distribution of bit patterns properties with their previous works. According to the comparison results, the proposed sequence holds better properties compared to our previous sequence.

DOI： 10.25046/aj040423

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

DOI： 10.1109/itc-cscc.2019.8793446

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

DOI： 10.1109/itc-cscc.2019.8793298

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

DOI： 10.1109/icce-tw46550.2019.8992033

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

DOI： 10.1109/icce-tw46550.2019.8991711

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

DOI： 10.1109/icce-tw46550.2019.8992029

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：ASTES Journal  

The distribution of bit patterns is an important measure to check the randomness of a sequence. The authors of this paper observed this crucial property in a binary sequence which generated by using a primitive polynomial, trace function, and Legendre symbol defined over the sub extension field. The authors create a new dimension in the sequence generation research area by considering the sub extension field, whereas all our previous works are focused in the prime field. In terms of distribution of bit patterns property, this research work has notable outcomes more specifically the binary sequence (defined over the sub extension field) holds much better (close to uniform) bit distribution than the previous binary sequence (defined over the prime field). Furthermore, the authors theoretically proved the distribution of bit property in this paper.

DOI： 10.25046/aj040246

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

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

Scopus

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

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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Authorship：Lead author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：Institute of Electronics, Information and Communications Engineers (IEICE)  

DOI： 10.1587/transfun.e101.a.1525

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

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

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

A pseudo-random sequence generated by using a primitive polynomial, trace function, and Legendre symbol has been researched in our previous work. Our previous sequence has some interesting features such as period, autocorrelation, and linear complexity. A pseudo-random sequence widely used in cryptography. However, from the aspect of the practical use in cryptographic systems sequence needs to generate swiftly. Our previous sequence generated by utilizing a primitive polynomial, however, finding a primitive polynomial requires high calculating cost when the degree or the characteristic is large. It's a shortcoming of our previous work. The main contribution of this work is to find some relation between the generated sequence and irreducible polynomials. The purpose of this relationship is to generate the same sequence without utilizing a primitive polynomial. From the experimental observation, it is found that there are (p - 1)/2 kinds of polynomial, which generates the same sequence. In addition, some of these polynomials are non-primitive polynomial. In this paper, these relationships between the sequence and the polynomials are shown by some examples. Furthermore, these relationships are proven theoretically also.

DOI： 10.6109/jicce.2018.16.3.166

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

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

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Authorship：Lead author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：EJournal Publishing  

DOI： 10.18178/ijiee.2018.8.1.685

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Language：English   Publishing type：Part of collection (book)   Publisher：Springer International Publishing  

Following the emergence of Kim and Barbulescu's new number field sieve (exTNFS) algorithm at CRYPTO'16 [21] for solving discrete logarithm problem (DLP) over the finite field; pairing-based cryptography researchers are intrigued to find new parameters that confirm standard security levels against exTNFS. Recently, Barbulescu and Duquesne have suggested new parameters [3] for well-studied pairing-friendly curves i.e., Barreto-Naehrig (BN) [5], Barreto-Lynn-Scott (BLS12) [4] and Kachisa-Schaefer-Scott (KSS-16) [19] curves at 128-bit security level (twist and sub-group attack secure). They have also concluded that in the context of Optimal-Ate pairing with their suggested parameters, BLS-12 and KSS-16 curves are more efficient choices than BN curves. Therefore, this paper selects the atypical and less studied pairingfriendly curve in literature, i.e., KSS-16 which offers quartic twist, while BN and BLS-12 curves have sextic twist. In this paper, the authors optimize Miller's algorithm of Optimal-Ate pairing for the KSS-16 curve by deriving efficient sparse multiplication and implement them. Furthermore, this paper concentrates on the Miller's algorithm to experimentally verify Barbulescu et al.'s estimation. The result shows that Miller's algorithm time with the derived pseudo 8-sparse multiplication is most efficient for KSS-16 than other two curves. Therefore, this paper defends Barbulescu and Duquesne's conclusion for 128-bit security.

DOI： 10.1007/978-3-319-71667-1_10

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

DOI： 10.1109/candar.2017.90

Scopus

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

DOI： 10.1109/candar.2017.86

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

DOI： 10.1109/icce-china.2017.7991033

Scopus

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

DOI： 10.1007/978-3-319-71667-1_10

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Other Link： https://dblp.uni-trier.de/db/conf/indocrypt/indocrypt2017.html#KhandakerNGDNK17

Language：English   Publishing type：Research paper (other academic)  

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Language：Japanese   Publishing type：Research paper, summary (national, other academic conference)  

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Language：Japanese   Publishing type：Research paper, summary (national, other academic conference)  

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Language：Japanese   Publishing type：Research paper, summary (national, other academic conference)  

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Language：Japanese   Publishing type：Internal/External technical report, pre-print, etc.  

J-GLOBAL

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Language：English   Publishing type：Research paper, summary (national, other academic conference)  

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Language：Japanese   Publishing type：Research paper, summary (national, other academic conference)  

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Language：Japanese   Publishing type：Research paper, summary (national, other academic conference)  

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Language：Japanese   Publishing type：Research paper, summary (national, other academic conference)  

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Language：Japanese   Publishing type：Research paper, summary (national, other academic conference)  

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Language：Japanese   Publishing type：Research paper, summary (national, other academic conference)  

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Language：Japanese   Publishing type：Research paper, summary (national, other academic conference)  

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J-GLOBAL

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Language：Japanese   Publishing type：Research paper, summary (national, other academic conference)  

J-GLOBAL

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Language：Japanese   Publishing type：Research paper, summary (national, other academic conference)  

J-GLOBAL

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Authorship：Lead author   Language：English   Publishing type：Research paper, summary (national, other academic conference)  

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Authorship：Lead author   Language：English   Publishing type：Research paper, summary (national, other academic conference)  

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Authorship：Lead author   Language：English   Publishing type：Research paper, summary (national, other academic conference)  

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Language：Japanese   Publishing type：Research paper, summary (national, other academic conference)  

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Language：Japanese   Publishing type：Research paper, summary (national, other academic conference)  

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Language：Japanese   Publishing type：Research paper, summary (national, other academic conference)  

J-GLOBAL

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Authorship：Lead author   Language：Japanese   Publishing type：Research paper, summary (national, other academic conference)  

J-GLOBAL

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Authorship：Lead author   Language：Japanese   Publishing type：Internal/External technical report, pre-print, etc.  

J-GLOBAL

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Type：Seminar, workshop

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Type：Seminar, workshop

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Type：Seminar, workshop

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