International Association for Cryptologic Research

International Association
for Cryptologic Research


Paper: Rotational-XOR Cryptanalysis of Reduced-round SPECK

Yunwen Liu , imec-COSIC KU Leuven, Leuven (Belgium); College of Science, National University of Defense Technology, Changsha
Glenn De Witte , imec-COSIC KU Leuven, Leuven
Adrián Ranea , imec-COSIC KU Leuven, Leuven
Tomer Ashur , imec-COSIC KU Leuven, Leuven
DOI: 10.13154/tosc.v2017.i3.24-36
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Abstract: In this paper we formulate a SAT/SMT model for Rotational-XOR (RX) cryptanalysis in ARX primitives for the first time. The model is successfully applied to the block cipher family Speck, and distinguishers covering more rounds than previously are found, as well as RX-characteristics requiring less data to detect. In particular, we present distinguishers for 10, 11 and 12 rounds for Speck32/64 which have better probabilities than the previously known 9-round differential characteristic, for a certain weak key class. For versions of Speck48, we present several distinguishers, among which the longest one covering 15 rounds, while the previously best differential characteristic only covered 11.
  title={Rotational-XOR Cryptanalysis of Reduced-round SPECK},
  journal={IACR Trans. Symmetric Cryptol.},
  publisher={Ruhr-Universit├Ąt Bochum},
  volume={2017, Issue 3},
  author={Yunwen Liu and Glenn De Witte and Adrián Ranea and Tomer Ashur},