Paper 2017/529

Non-Full Sbox Linearization: Applications to Collision Attacks on Round-Reduced Keccak

Ling Song, Guohong Liao, and Jian Guo


The Keccak hash function is the winner of the SHA-3 competition and became the SHA-3 standard of NIST in 2015. In this paper, we focus on practical collision attacks against round-reduced Keccak hash function, and two main results are achieved: the first practical collision attacks against 5-round Keccak-224 and an instance of 6-round Keccak collision challenge. Both improve the number of practically attacked rounds by one. These results are obtained by carefully studying the algebraic properties of the nonlinear layer in the underlying permutation of Keccak and applying linearization to it. In particular, techniques for partially linearizing the output bits of the nonlinear layer are proposed, utilizing which attack complexities are reduced significantly from the previous best results.

Available format(s)
Publication info
Published by the IACR in CRYPTO 2017
KeccakSHA-3hash functioncollisionnon-full linearizationadaptive
Contact author(s)
songling @ ntu edu sg
2017-06-07: received
Short URL
Creative Commons Attribution


      author = {Ling Song and Guohong Liao and Jian Guo},
      title = {Non-Full Sbox Linearization: Applications to Collision Attacks on Round-Reduced Keccak},
      howpublished = {Cryptology ePrint Archive, Paper 2017/529},
      year = {2017},
      note = {\url{}},
      url = {}
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