| Presentation | 2004/3/8 On the Importance of Protecting Δ in SFLASH against Side Channel Attacks Katsuyuki OKEYA, Tsuyoshi TAKAGI, Camille VUILLAUME, |
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| PDF Download Page | PDF download Page Link |
| Abstract(in Japanese) | (See Japanese page) |
| Abstract(in English) | SFLASH was chosen as one of the final selection of the NESSIE project in 2003. It is one of the most efficient digital signature scheme and is suitable for implementation on memory-constrained devices such as smartcards. Side channel attacks (SCA) are a serious threat to memory-constrained devices. If the implementation on them is careless, the secret key may be recovered. In this paper, we experimentally analyze the effectiveness of a side channel attack on SFLASH. There are two different secret keys for SFLASH, namely the proper secret key (s, t) and the random seed Δ used for the hash function SHA-1.s Whereas many papers discussed the security of (s, t), little is known about that of Δ. We propose a DPA on Δ using the addition operation modulo 2^<32>, and present an experimental result of the DPA. After obtaining the secret key Δ, the underlying problem of SFLASH can be reduced to the C^* problem broken by Patarin. From our simulation, about 1408 pairs of messages and signatures are needed to break SFLASH. Consequently, one has to carefully implement SHA-1 in order to resist SCA on SFLASH. |
| Keyword(in Japanese) | (See Japanese page) |
| Keyword(in English) | Asymmetric Signature / SFLASH / Side Channel Attacks / SHA-1 / C^* / C^<*--> / Hidden Monomial Problem |
| Paper # | IT2003-61,ISEC2003-101,WBS2003-179 |
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| Conference Information | |
| Committee | ISEC |
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| Conference Date | 2004/3/8(1days) |
| Place (in Japanese) | (See Japanese page) |
| Place (in English) | |
| Topics (in Japanese) | (See Japanese page) |
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| Paper Information | |
| Registration To | Information Security (ISEC) |
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| Language | ENG |
| Title (in Japanese) | (See Japanese page) |
| Sub Title (in Japanese) | (See Japanese page) |
| Title (in English) | On the Importance of Protecting Δ in SFLASH against Side Channel Attacks |
| Sub Title (in English) | |
| Keyword(1) | Asymmetric Signature |
| Keyword(2) | SFLASH |
| Keyword(3) | Side Channel Attacks |
| Keyword(4) | SHA-1 |
| Keyword(5) | C^* |
| Keyword(6) | C^<*--> |
| Keyword(7) | Hidden Monomial Problem |
| 1st Author's Name | Katsuyuki OKEYA |
| 1st Author's Affiliation | Hitachi, Ltd., SDL() |
| 2nd Author's Name | Tsuyoshi TAKAGI |
| 2nd Author's Affiliation | TU Darmstadt, Fachbereich Informatik Alexanderstr. |
| 3rd Author's Name | Camille VUILLAUME |
| 3rd Author's Affiliation | Hitachi, Ltd., SDL |
| Date | 2004/3/8 |
| Paper # | IT2003-61,ISEC2003-101,WBS2003-179 |
| Volume (vol) | vol.103 |
| Number (no) | 712 |
| Page | pp.pp.- |
| #Pages | 6 |
| Date of Issue | |