Cryptanalysis of Reduced-Round Midori64 Block Cipher

Xiaoyang Dong; Yanzhao Shen

Paper 2016/676

Cryptanalysis of Reduced-Round Midori64 Block Cipher

Xiaoyang Dong and Yanzhao Shen

Abstract

Midori is a hardware-oriented lightweight block cipher designed by Banik \emph{et al.} in ASIACRYPT 2015. It has two versions according to the state sizes, i.e. Midori64 and Midori128. In this paper, we explore the security of Midori64 against truncated differential and related-key differential attacks. By studying the compact representation of Midori64, we get the branching distribution properties of almost MDS matrix used by Midori64. By applying an automatic truncated differential search algorithm developed by Moriai \emph{et al.} in SAC 1999, we get 3137 4-round truncated differentials of Midori64. In addition, we find some 2-round iterative differential patterns for Midori64. By searching the differential characteristics matching the differential pattern, we find some iterative 2-round differentials with probability of $2^{-24}$, based on these differentials, a 11-round related-key differential characteristic is constructed. Then we mount a 14-round(out of 16 full rounds) related-key differential attack on Midori64. As far as we know, this is the first related-key differential attack on Midori64.

Metadata

Available format(s): PDF
Publication info: Preprint. MINOR revision.
Keywords: Block Cipher Truncated Differential Related-Key Differential Midori64
Contact author(s): dongxiaoyang @ mail sdu edu cn
History: 2016-07-09: last of 3 revisions; 2016-07-06: received; See all versions
Short URL: https://ia.cr/2016/676
License: CC BY

BibTeX

@misc{cryptoeprint:2016/676,
      author = {Xiaoyang Dong and Yanzhao Shen},
      title = {Cryptanalysis of Reduced-Round Midori64 Block Cipher},
      howpublished = {Cryptology {ePrint} Archive, Paper 2016/676},
      year = {2016},
      url = {https://eprint.iacr.org/2016/676}
}