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| Cryptanalysis of Helix and Phelix revisited | |
| Shi, Zhenqing (1); Zhang, Bin (2); Feng, Dengguo (1) | |
| 2013 | |
| Conference Name | 18th Australasian Conference on Information Security and Privacy, ACISP 2013 |
| Pages | 27-40 |
| Conference Date | July 1, 2013 - July 3, 2013 |
| Conference Place | Brisbane, QLD, Australia |
| Indexed Type | EI |
| Publish Place | Springer Verlag, Tiergartenstrasse 17, Heidelberg, D-69121, Germany |
| ISSN | 3029743 |
| ISBN | 9783642390586 |
| Department | (1) Institute of Software, Chinese Academy of Sciences, Beijing, 100190, China; (2) State Key Laboratory of Information Security, Institute of Information Engineering, Chinese Academy of Sciences, Beijing, 100195, China |
| English Abstract | Helix, designed by Ferguson et al., is a high-speed asynchronous stream cipher with a built-in MAC functionality. At FSE 2004, Muller presented two attacks on Helix. Motivated by these attacks, Phelix was proposed and selected as a Phase 2 focus cipher for both Profile 1 and Profile 2 by the eSTREAM project, but was not advanced to Phase 3 mainly due to a key recovery attack by Wu and Preneel when the prohibition against reusing a nonce is violated. In this paper, we study the security of Helix and Phelix in the more realistic chosen nonce model. We first point out a flaw in Muller's second attack, which results in the failure of his attack. Then we propose our distinguishing attack on Helix with a data complexity of 2132, faster than exhaustive search when the key length is larger than 132 bits. Furthermore, when the maximal length of output keystream is extended, the data complexity can be reduced to 2 127 and we also can construct a key recovery attack with a data complexity of 2163. Since this flaw is overlooked by the designers of Phelix, we can extend the distinguishing attack to Phelix with the same complexity, which shows that Phelix fails to strengthen Helix against internal state collision attacks. Our results provide new insights on the design of such dedicated ciphers with built-in authentication. © 2013 Springer-Verlag.; Helix, designed by Ferguson et al., is a high-speed asynchronous stream cipher with a built-in MAC functionality. At FSE 2004, Muller presented two attacks on Helix. Motivated by these attacks, Phelix was proposed and selected as a Phase 2 focus cipher for both Profile 1 and Profile 2 by the eSTREAM project, but was not advanced to Phase 3 mainly due to a key recovery attack by Wu and Preneel when the prohibition against reusing a nonce is violated. In this paper, we study the security of Helix and Phelix in the more realistic chosen nonce model. We first point out a flaw in Muller's second attack, which results in the failure of his attack. Then we propose our distinguishing attack on Helix with a data complexity of 2132, faster than exhaustive search when the key length is larger than 132 bits. Furthermore, when the maximal length of output keystream is extended, the data complexity can be reduced to 2 127 and we also can construct a key recovery attack with a data complexity of 2163. Since this flaw is overlooked by the designers of Phelix, we can extend the distinguishing attack to Phelix with the same complexity, which shows that Phelix fails to strengthen Helix against internal state collision attacks. Our results provide new insights on the design of such dedicated ciphers with built-in authentication. © 2013 Springer-Verlag. |
| Language | 英语 |
| Content Type | 会议论文 |
| URI | http://ir.iscas.ac.cn/handle/311060/16668 |
| Collection | 中国科学院软件研究所 |
| Recommended Citation GB/T 7714 | Shi, Zhenqing ,Zhang, Bin ,Feng, Dengguo . Cryptanalysis of Helix and Phelix revisited[C]. Springer Verlag, Tiergartenstrasse 17, Heidelberg, D-69121, Germany,2013:27-40. |
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