| Presentation | 2002/9/13 The (Im)Possibility of Asymmetric Authentication Codes with Dishonest Arbiters Goichiro HANAOKA, Junji SHIKATA, Yumiko HANAOKA, Hideki IMAI, |
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| PDF Download Page | PDF download Page Link |
| Abstract(in Japanese) | (See Japanese page) |
| Abstract(in English) | Authentication codes (A-codes, for short) are considered to be important building blocks for constructing unconditionally secure authentication schemes. As an extension of A-codes with the aim of enhancing them with non-repudiation property, A^2-codes was introduced by Simmons. Later, Johansson formally defined an improved version of A^2-codes called, the A^3-codes. Unlike A^2-codes, A^3-codes did not require a trusted arbiter. In this paper, we point out a flaw in the definition of A^3-codes and show a concrete attack against an A^3-code. The A-code satisfies the requirement of A^3-codes, however, under our attack, an arbiter succeeds impersonation. This signifies that the definition of A^3-codes may be falsely defined, and accordingly, implies that the concrete constructions of A^3-codes could be insecure without a trusted arbiter. We also show that there is no significant difference between A^2-codes and A^3-codes in a practical sense and further argue that it is impossible to construct an "ideal" A^3-codes that is, without a trusted arbiter. Finally, we introduce a novel model of asymmetric A-codes with arbiters that are not fully trusted, and show a concrete construction of the asymmetric A-codes for the model. Since our proposed A-code does not require fully trusted arbiters, we can say that it is more secure than an A^2-code or an A^3-code. |
| Keyword(in Japanese) | (See Japanese page) |
| Keyword(in English) | Authentication codes / Arbitration / Unconditional Security |
| Paper # | ISEC2002-69 |
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| Conference Information | |
| Committee | ISEC |
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| Conference Date | 2002/9/13(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) | The (Im)Possibility of Asymmetric Authentication Codes with Dishonest Arbiters |
| Sub Title (in English) | |
| Keyword(1) | Authentication codes |
| Keyword(2) | Arbitration |
| Keyword(3) | Unconditional Security |
| 1st Author's Name | Goichiro HANAOKA |
| 1st Author's Affiliation | Institute of Industrial Science, University of Tokyo:Reseach Fellow of Japan Society of the Promotion of Science() |
| 2nd Author's Name | Junji SHIKATA |
| 2nd Author's Affiliation | Graduate School of Environment and Information Sciences, Yokohama National University |
| 3rd Author's Name | Yumiko HANAOKA |
| 3rd Author's Affiliation | Multimedia Laboratories, NTT DocoMo, Inc. |
| 4th Author's Name | Hideki IMAI |
| 4th Author's Affiliation | Institute of Industrial Science, University of Tokyo |
| Date | 2002/9/13 |
| Paper # | ISEC2002-69 |
| Volume (vol) | vol.102 |
| Number (no) | 323 |
| Page | pp.pp.- |
| #Pages | 6 |
| Date of Issue | |