| Presentation | 2020-05-20 Making Variance of Mining Time Smaller for Computational Problems Based on Hash Functions Hiroaki Anada, Kouichi Sakurai, |
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| PDF Download Page |  PDF download Page Link |
| Abstract(in Japanese) | (See Japanese page) |
| Abstract(in English) | In Bitcoin, the computational problem which miners should solve is an equation described in the term of a hash function. The time (emph{mining time}) needed to solve the problem is known to follow the exponential distribution. The exponential distribution has the property that, when the expectation is fixed, the variance is also fixed to be the square of the expectation. This property is not preferable from the view point of possible vulnerability on information security. In this report, we evaluate two types of computational problems that are constructed from the computational problem of Bitcoin. The first type is serial concatenation and the second type is parallel concatenation. The times needed to solve the problems become the sum and the maximum of the times for the components, respectively. Using these properties, we state quantitively the results that the variances of the times are decreased. Finally, we mention as a trade-off that the data size of a block on the blockchain is increased. |
| Keyword(in Japanese) | (See Japanese page) |
| Keyword(in English) | Bitcoin / blockchain / hash function / mining time / exponential distribution / central limit theorem |
| Paper # | ISEC2020-9 |
| Date of Issue | 2020-05-13 (ISEC) |
| Conference Information | |
| Committee | ISEC |
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| Conference Date | 2020/5/20(1days) |
| Place (in Japanese) | (See Japanese page) |
| Place (in English) | Online |
| Topics (in Japanese) | (See Japanese page) |
| Topics (in English) | |
| Chair | Shiho Moriai(NICT) |
| Vice Chair | Shoichi Hirose(Univ. of Fukui) / Tetsuya Izu(Fujitsu Labs.) |
| Secretary | Shoichi Hirose(NICT) / Tetsuya Izu(Tsukuba Univ.) |
| Assistant | Dai Yamamoto(Fujitsu Labs.) / Yuuji Suga(IIJ) |
| Paper Information | |
| Registration To | Technical Committee on Information Security |
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| Language | JPN |
| Title (in Japanese) | (See Japanese page) |
| Sub Title (in Japanese) | (See Japanese page) |
| Title (in English) | Making Variance of Mining Time Smaller for Computational Problems Based on Hash Functions |
| Sub Title (in English) | Serial Concatenation and Parallel Concatenation |
| Keyword(1) | Bitcoin |
| Keyword(2) | blockchain |
| Keyword(3) | hash function |
| Keyword(4) | mining time |
| Keyword(5) | exponential distribution |
| Keyword(6) | central limit theorem |
| 1st Author's Name | Hiroaki Anada |
| 1st Author's Affiliation | University of Nagasaki(Univ. Nagasaki) |
| 2nd Author's Name | Kouichi Sakurai |
| 2nd Author's Affiliation | Kyushu University(Kyushu Univ.) |
| Date | 2020-05-20 |
| Paper # | ISEC2020-9 |
| Volume (vol) | vol.120 |
| Number (no) | ISEC-28 |
| Page | pp.pp.33-40(ISEC), |
| #Pages | 8 |
| Date of Issue | 2020-05-13 (ISEC) |