| Presentation | 2017-09-04 Provably Secure Code-Based Signature Schemes via Fiat-Shamir Transform with Theoretical and Practical Analysis on Hash Encodings Taiyo Yamaguchi, Bagus Santoso, |
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| PDF Download Page |  PDF download Page Link |
| Abstract(in Japanese) | (See Japanese page) |
| Abstract(in English) | In this paper, we propose signature schemes constructed from code-based identification scheme proposed by Stern via Fiat-Shamir transform. In Fiat-Shamir transform, the ``challenge'' part of the identification is substituted with the output of hash function. However, our observation reveals that the ``challenge'' part of Stern's identification scheme is taken from the set of ${0,1,2}$, while all standard hash functions, e.g., SHA-1, SHA-256, outputs a sequence of bits or values in ${0,1}$. We define two emph{explicit} different encodings of the hash function's outputs into the ``challenge'' part and based on them, we build two different constructions of signature schemes. We discover that these encodings are not only giving impacts on the implementation cost in emph{practical} side, but also giving non-negligible amount of impacts on the security parameter for achieving provable security in emph{theoretical} side. As a rough illustration, letting $varepsilon$ denote the success probability of breaking emph{decisional} version of syndrome decoding problem and $r$ be the number of rounds required to guarantee the soundness of identification scheme, we show that one type of encoding gives a scheme with probability of successful signing half and adversary's success probability approximately upper bounded by $varepsilon+(2/3)^r$, while the other one gives a scheme with probability of successful signing one and adversary's success probability approximately upper bounded by $varepsilon+(3/4)^r$. |
| Keyword(in Japanese) | (See Japanese page) |
| Keyword(in English) | syndrome decoding problemsignature schemeidentification schemeFiat-Shamir transformhash function |
| Paper # | ISEC2017-46 |
| Date of Issue | 2017-08-28 (ISEC) |
| Conference Information | |
| Committee | ISEC |
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| Conference Date | 2017/9/4(1days) |
| Place (in Japanese) | (See Japanese page) |
| Place (in English) | Kikai-Shinko-Kaikan Bldg. |
| Topics (in Japanese) | (See Japanese page) |
| Topics (in English) | |
| Chair | Kazuto Ogawa(NHK) |
| Vice Chair | Atsushi Fujioka(Kanagawa Univ.) / Shiho Moriai(NICT) |
| Secretary | Atsushi Fujioka(Tohoku Univ.) / Shiho Moriai(Tokai Univ.) |
| Assistant | Keita Emura(NICT) / Yuichi Komano(TOSHIBA) / Yuuji Suga(IIJ) |
| Paper Information | |
| Registration To | Technical Committee on Information Security |
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| Language | ENG |
| Title (in Japanese) | (See Japanese page) |
| Sub Title (in Japanese) | (See Japanese page) |
| Title (in English) | Provably Secure Code-Based Signature Schemes via Fiat-Shamir Transform with Theoretical and Practical Analysis on Hash Encodings |
| Sub Title (in English) | |
| Keyword(1) | syndrome decoding problemsignature schemeidentification schemeFiat-Shamir transformhash function |
| 1st Author's Name | Taiyo Yamaguchi |
| 1st Author's Affiliation | University of Electro-Communications(UEC) |
| 2nd Author's Name | Bagus Santoso |
| 2nd Author's Affiliation | University of Electro-Communications(UEC) |
| Date | 2017-09-04 |
| Paper # | ISEC2017-46 |
| Volume (vol) | vol.117 |
| Number (no) | ISEC-202 |
| Page | pp.pp.35-42(ISEC), |
| #Pages | 8 |
| Date of Issue | 2017-08-28 (ISEC) |