A comparison of local reduction and SAT-solver based algebraic cryptanalysis of JH and Keccak

Abstract

Local reduction methods can be used to assess the resistance of
cryptosystems against algebraic attacks. The assessment is based on the separation
of the attack into polynomial-time reduction algorithm, and exponential
time guessing and backtracking. This approach is similar to that employed by
the DPLL algorithm that is used as a core of various modern SAT-solvers. In the
article we show the application of this method to evaluate the strength of (reduced
versions of) two chosen SHA-3 candidates: JH, and Keccak, respectively.
We compare the complexity estimates with the behavior of the full search algorithm.
We also compare the results based on the local reduction with the attack
based on the use of SAT-solvers PrecoSAT, and CryptoMiniSAT, respectively.