Journal of Mathematical Cryptology (Sep 2018)

MRHS solver based on linear algebra and exhaustive search

  • Raddum Håvard,
  • Zajac Pavol

DOI
https://doi.org/10.1515/jmc-2017-0005
Journal volume & issue
Vol. 12, no. 3
pp. 143 – 157

Abstract

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We show how to build a binary matrix from the MRHS representation of a symmetric-key cipher. The matrix contains the cipher represented as an equation system and can be used to assess a cipher’s resistance against algebraic attacks. We give an algorithm for solving the system and compute its complexity. The complexity is normally close to exhaustive search on the variables representing the user-selected key. Finally, we show that for some variants of LowMC, the joined MRHS matrix representation can be used to speed up regular encryption in addition to exhaustive key search.

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