Paper 2010/166

Fault Analysis Study of the Block Cipher FOX64

Ruilin Li, Jianxiong You, Bing Sun, and Chao Li


FOX is a family of symmetric block ciphers from MediaCrypt AG that helps to secure digital media, communications, and storage. The high-level structure of FOX is the so-called (extended) Lai-Massey scheme. This paper presents a detailed fault analysis of the block cipher FOX64, the 64-bit version of FOX, based on a differential property of tworound Lai-Massey scheme in a fault model. Previous fault attack on FOX64 shows that each round-key (resp. whole round-keys) could be recovered through 11.45 (resp. 183.20) faults on average. Our proposed fault attack, however, can deduce any round-key (except the first one) through 4.25 faults on average (4 in the best case), and retrieve the whole round-keys through 43.31 faults on average (38 in the best case). This implies that the number of needed faults in the fault attack on FOX64 can be significantly reduced. Furthermore, the technique introduced in this paper can be extended to other series of the block cipher family FOX.

Available format(s)
Secret-key cryptography
Publication info
Published elsewhere. To be published in Multimedia Tools and Applications
Side-channel attacksFault attacksBlock ciphersLai-Massey schemeFOX
Contact author(s)
securitylrl @ gmail com
2011-10-29: last of 3 revisions
2010-03-30: received
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Creative Commons Attribution


      author = {Ruilin Li and Jianxiong You and Bing Sun and Chao Li},
      title = {Fault Analysis Study of the Block Cipher FOX64},
      howpublished = {Cryptology ePrint Archive, Paper 2010/166},
      year = {2010},
      note = {\url{}},
      url = {}
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