| automatic search of truncated impossible differentials for word-oriented block ciphers |
| Wu Shengbao; Wang Mingsheng
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| 2012
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| 会议名称 | 13th International Conference on Cryptology in India, INDOCRYPT 2012
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| 会议录名称 | Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics)
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| 页码 | 283-302
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| 会议日期 | December 9, 2012 - December 12, 2012
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| 会议地点 | Kolkata, India
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| 收录类别 | EI
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| ISSN | 0302-9743
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| ISBN | 9783642349300
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| 部门归属 | (1) Institute of Software Chinese Academy of Sciences PO Box 8718 Beijing 100190 China; (2) Graduate School of Chinese Academy of Sciences Beijing 100190 China; (3) State Key Laboratory of Information Security Institute of Information Engineering Beijing China
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| 摘要 | Impossible differential cryptanalysis is a powerful technique to recover the secret key of block ciphers by exploiting the fact that in block ciphers specific input and output differences are not compatible. This paper introduces a novel tool to search truncated impossible differentials for word-oriented block ciphers with bijective Sboxes. Our tool generalizes the earlier μ-method and the UID-method. It allows to reduce the gap between the best impossible differentials found by these methods and the best known differentials found by ad hoc methods that rely on cryptanalytic insights. The time and space complexities of our tool in judging an r-round truncated impossible differential are about O(c·l4·r4) and O(c′·l2·r2) respectively, where l is the number of words in the plaintext and c, c′ are constants depending on the machine and the block cipher. In order to demonstrate the strength of our tool, we show that it does not only allow to automatically rediscover the longest truncated impossible differentials of many word-oriented block ciphers, but also finds new results. It independently rediscovers all 72 known truncated impossible differentials on 9-round CLEFIA. In addition, it finds new truncated impossible differentials for AES, ARIA, Camellia without FL and FL-1 layers, E2, LBlock, MIBS and Piccolo. Although our tool does not improve the lengths of impossible differentials for existing block ciphers, it helps to close the gap between the best known results of previous tools and those of manual cryptanalysis. © Springer-Verlag 2012.; Impossible differential cryptanalysis is a powerful technique to recover the secret key of block ciphers by exploiting the fact that in block ciphers specific input and output differences are not compatible. This paper introduces a novel tool to search truncated impossible differentials for word-oriented block ciphers with bijective Sboxes. Our tool generalizes the earlier μ-method and the UID-method. It allows to reduce the gap between the best impossible differentials found by these methods and the best known differentials found by ad hoc methods that rely on cryptanalytic insights. The time and space complexities of our tool in judging an r-round truncated impossible differential are about O(c·l4·r4) and O(c′·l2·r2) respectively, where l is the number of words in the plaintext and c, c′ are constants depending on the machine and the block cipher. In order to demonstrate the strength of our tool, we show that it does not only allow to automatically rediscover the longest truncated impossible differentials of many word-oriented block ciphers, but also finds new results. It independently rediscovers all 72 known truncated impossible differentials on 9-round CLEFIA. In addition, it finds new truncated impossible differentials for AES, ARIA, Camellia without FL and FL-1 layers, E2, LBlock, MIBS and Piccolo. Although our tool does not improve the lengths of impossible differentials for existing block ciphers, it helps to close the gap between the best known results of previous tools and those of manual cryptanalysis. © Springer-Verlag 2012. |
| 关键词 | Lyapunov Methods
Security Of Data
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| 主办者 | Defence Research and Developement Organization (D.R.D.O.); Google Inc.; Microsoft Research; National Board of Higher Mathematics (N.B.H.M.); Reserve Bank of India (R.B.I.); Tata Consultancy Services (T.C.S.)
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| 语种 | 英语
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| 内容类型 | 会议论文
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| URI标识 | http://ir.iscas.ac.cn/handle/311060/15848
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| 专题 | 中国科学院软件研究所
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推荐引用方式
GB/T 7714 |
Wu Shengbao,Wang Mingsheng. automatic search of truncated impossible differentials for word-oriented block ciphers[C],2012:283-302.
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