| Presentation | 1997/11/20 How to Prove (Non-) Existence of a Key Word As a Substring in Encrypted Messages Takako Ito, Hiroki Shizuya, |
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| PDF Download Page | PDF download Page Link |
| Abstract(in Japanese) | (See Japanese page) |
| Abstract(in English) | Let f be an encryption function such that C=f(m). The problem we consider in this paper is, given C and a key word K, to determine whether K is contained as a substring in m or not. We show that this problem is equivalent to computing f^<-1> with respect to the polynomial-time Turing reducibility. This means that we cannot expect efficient algorithms for the problem. However; we also show that (non-)existence of K as a substring in m can be demonstrated in computational zero-knowledge if f is a group-isomorphic encryption function. We construct interactive protocols for the language and its complement equivalent to this decision problem without reducing them to an NP-complete language. |
| Keyword(in Japanese) | (See Japanese page) |
| Keyword(in English) | encryption function / elliptic curve / zero-knowledge |
| Paper # | ISEC97-52 |
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| Conference Information | |
| Committee | ISEC |
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| Conference Date | 1997/11/20(1days) |
| Place (in Japanese) | (See Japanese page) |
| Place (in English) | |
| Topics (in Japanese) | (See Japanese page) |
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| Vice Chair | |
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| Paper Information | |
| Registration To | Information Security (ISEC) |
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| Language | JPN |
| Title (in Japanese) | (See Japanese page) |
| Sub Title (in Japanese) | (See Japanese page) |
| Title (in English) | How to Prove (Non-) Existence of a Key Word As a Substring in Encrypted Messages |
| Sub Title (in English) | |
| Keyword(1) | encryption function |
| Keyword(2) | elliptic curve |
| Keyword(3) | zero-knowledge |
| 1st Author's Name | Takako Ito |
| 1st Author's Affiliation | Department of Computer and Mathematical Sciences, Graduate School of Information Sciences, Tohoku University() |
| 2nd Author's Name | Hiroki Shizuya |
| 2nd Author's Affiliation | Department of Computer and Mathematical Sciences, Graduate School of Information Sciences, Tohoku University |
| Date | 1997/11/20 |
| Paper # | ISEC97-52 |
| Volume (vol) | vol.97 |
| Number (no) | 381 |
| Page | pp.pp.- |
| #Pages | 10 |
| Date of Issue | |