| Title: | improved linear analysis on block cipher multi2 |
| Author: | Lu Yi
; Ding Liping
; Wang Yongji
|
| Source: | Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics)
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| Conference Name: | 11th International Conference on Cryptology and Network Security, CANS 2012
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| Conference Date: | December 12, 2012 - December 14, 2012
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| Issued Date: | 2012
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| Conference Place: | Darmstadt, Germany
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| Keyword: | Network security
; Recovery
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| Indexed Type: | EI
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| ISSN: | 0302-9743
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| ISBN: | 9783642354038
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| Department: | (1) National Engineering Research Center of Fundamental Software Institute of Software Chinese Academy of Sciences Beijing China
|
| Abstract: | Developed by Hitachi, MULTI2 is a block cipher used mainly to secure the multimedia content. It was registered in ISO/IEC 9979 and was patented in US and Japan. MULTI2 uses the Feistel structure and operates on the 64-bit blocks. The encryption key has 256 bits. This paper studies the linear analysis on MULTI2. We give a detailed bias analysis on MULTI2 round functions. For the first time formal proofs on their bias properties are given. This allows to find a new 4-round bias 2-2. Previously, the best 4-round bias 2-5.7 was proposed. Using our results on the MULTI2 round functions, we propose the linear attacks on r-round MUTLI2 to recover the encryption key. Our linear attack can recover the 256-bit encryption key in time 246, 2 60.4, 283.8, 291.7, 2123.4, 2 123.2 of r-round encryptions for r = 8, 12, 16, 20, 24, 28 respectively. Further, we can recover the 32-bit sub-key in last round much faster than the whole encryption key recovery, i.e., in time 237 for r = 8, 12, 16, 20, 24. Note that previously, the best linear key-recovery attack was a 20-round attack with time 293.4 (of 20-round encryptions) and data 239.2. As ISO register recommends to use at least 32 rounds, our attacks remain to be theoretical and do not threaten security for the practical use currently. © Springer-Verlag 2012. |
| English Abstract: | Developed by Hitachi, MULTI2 is a block cipher used mainly to secure the multimedia content. It was registered in ISO/IEC 9979 and was patented in US and Japan. MULTI2 uses the Feistel structure and operates on the 64-bit blocks. The encryption key has 256 bits. This paper studies the linear analysis on MULTI2. We give a detailed bias analysis on MULTI2 round functions. For the first time formal proofs on their bias properties are given. This allows to find a new 4-round bias 2-2. Previously, the best 4-round bias 2-5.7 was proposed. Using our results on the MULTI2 round functions, we propose the linear attacks on r-round MUTLI2 to recover the encryption key. Our linear attack can recover the 256-bit encryption key in time 246, 2 60.4, 283.8, 291.7, 2123.4, 2 123.2 of r-round encryptions for r = 8, 12, 16, 20, 24, 28 respectively. Further, we can recover the 32-bit sub-key in last round much faster than the whole encryption key recovery, i.e., in time 237 for r = 8, 12, 16, 20, 24. Note that previously, the best linear key-recovery attack was a 20-round attack with time 293.4 (of 20-round encryptions) and data 239.2. As ISO register recommends to use at least 32 rounds, our attacks remain to be theoretical and do not threaten security for the practical use currently. © Springer-Verlag 2012. |
| Language: | 英语
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| Content Type: | 会议论文
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| URI: | http://ir.iscas.ac.cn/handle/311060/15821
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| Appears in Collections: | 软件所图书馆_会议论文
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| Recommended Citation: | |
Lu Yi,Ding Liping,Wang Yongji. improved linear analysis on block cipher multi2[C]. 见:11th International Conference on Cryptology and Network Security, CANS 2012. Darmstadt, Germany. December 12, 2012 - December 14, 2012.
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