Paper 2017/1036 Original: eprint.iacr.org/2017/1036 ↗

Rotational-XOR Cryptanalysis of Reduced-round SPECK

Yunwen Liu
Glenn De Witte
Adrián Ranea
Tomer Ashur
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.

Metadata
Available format(s)
PDF
Category
Secret-key cryptography
Publication info
Preprint.
History
2017-10-28: last updated
2017-10-28: published
Short URL
https://ia.cr/2017/1036
License
https://creativecommons.org/licenses/by/4.0/

BibTeX

@misc{cryptoeprint:2017/1036,
      author = {Yunwen Liu and Glenn De Witte and Adrián Ranea and Tomer Ashur},
      title = {Rotational-XOR Cryptanalysis of Reduced-round SPECK},
      howpublished = {Cryptology {ePrint} Archive, Paper 2017/1036},
      year = {2017},
      url = {https://eprint.iacr.org/2017/1036}
}
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