Related-key differential attacks on Cobra-H64 and Cobra-H128

Changhoon Lee, Jongsung Kim, Jaechul Sung, Seokhie Hong, Sangjin Lee, Dukjae Moon

Research output: Chapter in Book/Report/Conference proceedingConference contribution

13 Citations (Scopus)

Abstract

Cobra-H64 and Cobra-H128, which use data-dependent permutations as a main cryptographic primitive, are 64-bit and 128-bit iterated block ciphers with 128-bit and 256-bit keys, respectively. Since these ciphers use very simple key scheduling and controlled permutation (CP) for fast hardware encryption, they are suitable for wireless communications networks which require high-speed networks. Actually, these ciphers have better hardware performances than other ciphers used in security layers of wireless protocols (Wap, OMA, UMTS, IEEE 802.11 and so on). In this paper, however, we show that Cobra-H64 and Cobra-H128 are vulnerable to related-key differential attacks. We first describe how to construct full-round related-key differential characteristics of Cobra-H64 and Cobra-H128 with high probabilities and then we exploit them to attack full-round Cobra-H64 with a complexity of 215.5 and Cobra-H128 with a complexity of 244.

Original languageEnglish
Title of host publicationCryptography and Coding - 10th IMA International Conference, Proceedings
PublisherSpringer Verlag
Pages201-219
Number of pages19
ISBN (Print)354030276X, 9783540302766
DOIs
Publication statusPublished - 2005
Event10th IMA International Conference on Cryptography and Coding - Cirencester, United Kingdom
Duration: 2005 Dec 192005 Dec 21

Publication series

NameLecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics)
Volume3796 LNCS
ISSN (Print)0302-9743
ISSN (Electronic)1611-3349

Other

Other10th IMA International Conference on Cryptography and Coding
CountryUnited Kingdom
CityCirencester
Period05/12/1905/12/21

Keywords

  • Block Ciphers
  • Cobra-H128
  • Cobra-H64
  • Data-Dependent Permutations
  • Related-Key At-tacks

ASJC Scopus subject areas

  • Theoretical Computer Science
  • Computer Science(all)

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  • Cite this

    Lee, C., Kim, J., Sung, J., Hong, S., Lee, S., & Moon, D. (2005). Related-key differential attacks on Cobra-H64 and Cobra-H128. In Cryptography and Coding - 10th IMA International Conference, Proceedings (pp. 201-219). (Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics); Vol. 3796 LNCS). Springer Verlag. https://doi.org/10.1007/11586821_14