Related-Key Boomerang and Rectangle Attacks

  • Eli Biham
  • Orr Dunkelman
  • Nathan Keller
Part of the Lecture Notes in Computer Science book series (LNCS, volume 3494)

Abstract

The boomerang attack and the rectangle attack are two attacks that utilize differential cryptanalysis in a larger construction. Both attacks treat the cipher as a cascade of two sub-ciphers, where there exists a good differential for each sub-cipher, but not for the entire cipher. In this paper we combine the boomerang (and the rectangle) attack with related-key differentials.

The new combination is applicable to many ciphers, and we demonstrate its strength by introducing attacks on reduced-round versions of AES and IDEA. The attack on 192-bit key 9-round AES uses 256 different related keys. The 6.5-round attack on IDEA uses four related keys (and has time complexity of 288.1 encryptions). We also apply these techniques to COCONUT98 to obtain a distinguisher that requires only four related-key adaptive chosen plaintexts and ciphertexts. For these ciphers, our results attack larger number of rounds or have smaller complexities then all previously known attacks.

Copyright information

© Springer-Verlag Berlin Heidelberg 2005

Authors and Affiliations

  • Eli Biham
    • 1
  • Orr Dunkelman
    • 1
  • Nathan Keller
    • 2
  1. 1.Computer Science DepartmentTechnionHaifaIsrael
  2. 2.Einstein Institute of MathematicsHebrew UniversityJerusalemIsrael

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