International Workshop on Fast Software Encryption

FSE 2011: Fast Software Encryption pp 18-34

Search for Related-Key Differential Characteristics in DES-Like Ciphers

  • Alex Biryukov
  • Ivica Nikolić
Conference paper

DOI: 10.1007/978-3-642-21702-9_2

Volume 6733 of the book series Lecture Notes in Computer Science (LNCS)
Cite this paper as:
Biryukov A., Nikolić I. (2011) Search for Related-Key Differential Characteristics in DES-Like Ciphers. In: Joux A. (eds) Fast Software Encryption. FSE 2011. Lecture Notes in Computer Science, vol 6733. Springer, Berlin, Heidelberg

Abstract

We present the first automatic search algorithms for the best related-key differential characteristics in DES-like ciphers. We show that instead of brute-forcing the space of all possible differences in the master key and the plaintext, it is computationally more efficient to try only a reduced set of input-output differences of three consecutive S-box layers. Based on this observation, we propose two search algorithms – the first explores Matsui’s approach, while the second is divide-and-conquer technique. Using our algorithms, we find the probabilities (or the upper bounds on the probabilities) of the best related-key characteristics in DES, DESL, and s2DES.

Keywords

Cryptanalysis toolautomatic searchdifferential characteristicrelated-key attackDES
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Copyright information

© Springer-Verlag Berlin Heidelberg 2011

Authors and Affiliations

  • Alex Biryukov
    • 1
  • Ivica Nikolić
    • 1
  1. 1.University of LuxembourgLuxembourg