Paper 2010/485

Cryptanalysis of Block Ciphers Using Almost-Impossible Differentials

Hamid Mala, Mohammad Dakhilalian, and Mohsen Shakiba


In this paper, inspired from the notion of impossible differentials, we present a model to use differentials that are less probable than a random permutation. We introduce such a distinguisher for 2 rounds of Crypton, and present an attack on 6 rounds of this predecessor AES candidate. As a special case of this idea, we embed parts of the additional rounds around the impossible differential into the distinguisher to make a probabilistic distinguisher with more rounds. We show that with this change, the data complexity is increased but the time complexity may be reduced or increased. Then we discuss that this change in the impossible differential cryptanalysis is commodious and rational when the data complexity is low and time complexity is marginal.

Available format(s)
Secret-key cryptography
Publication info
Published elsewhere. Unknown where it was published
Block CipherCryptanalysisAlmost-Impossible DifferentialCrypton
Contact author(s)
hamidmala2003 @ yahoo com
2010-09-15: received
Short URL
Creative Commons Attribution


      author = {Hamid Mala and Mohammad Dakhilalian and Mohsen Shakiba},
      title = {Cryptanalysis of Block Ciphers Using Almost-Impossible Differentials},
      howpublished = {Cryptology ePrint Archive, Paper 2010/485},
      year = {2010},
      note = {\url{}},
      url = {}
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