Rotational-XOR Cryptanalysis of Reduced-round SPECK

Authors

  • Yunwen Liu imec - Computer Security and Industrial Cryptography (COSIC) research group, Department of Electrical Engineering (ESAT), KU Leuven, Leuven, Belgium; College of Science, National University of Defense Technology, Changsha, China
  • Glenn De Witte imec - Computer Security and Industrial Cryptography (COSIC) research group, Department of Electrical Engineering (ESAT), KU Leuven, Leuven, Belgium
  • Adrián Ranea imec - Computer Security and Industrial Cryptography (COSIC) research group, Department of Electrical Engineering (ESAT), KU Leuven, Leuven, Belgium
  • Tomer Ashur imec - Computer Security and Industrial Cryptography (COSIC) research group, Department of Electrical Engineering (ESAT), KU Leuven, Leuven, Belgium

DOI:

https://doi.org/10.13154/tosc.v2017.i3.24-36

Keywords:

Rotational cryptanalysis, ARX, RX-difference, Weak keys, SAT/SMT

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.

Downloads

Published

2017-09-19

Issue

Volume 2017, Issue 3

Section

Articles

License

Copyright (c) 2017 Yunwen Liu, Glenn De Witte, Adrián Ranea, Tomer Ashur

Creative Commons License

This work is licensed under a Creative Commons Attribution 4.0 International License.

How to Cite

Rotational-XOR Cryptanalysis of Reduced-round SPECK. (2017). IACR Transactions on Symmetric Cryptology, 2017(3), 24-36. https://doi.org/10.13154/tosc.v2017.i3.24-36