On the Data Complexity of Statistical Attacks Against Block Ciphers

Céline Blondeau (1) , Benoît Gérard (1)

1 SECRET - Security, Cryptology and Transmissions

Many attacks on iterated block ciphers rely on statistical considerations using plaintext/ciphertext pairs to distinguish some part of the cipher from a random permutation. We provide here a simple formula for estimating the amount of plaintext/ciphertext pairs which is needed for such distinguishers and which applies to a lot of different scenarios (linear cryptanalysis, differentiallinear cryptanalysis, differential/truncated differential/impossible differential cryptanalysis). The asymptotic data complexities of all these attacks are then derived. Moreover, we give an efficient algorithm for computing the data complexity accurately.

Mots clés: statistical cryptanalysis; iterated block cipher; data complexity

Domaines: Théorie de l'information et codage [math.IT]; Théorie de l'information [cs.IT]

Céline Blondeau, Benoît Gérard. On the Data Complexity of Statistical Attacks Against Block Ciphers. WCC 2009 - Workshop on Coding and Cryptography, May 2009, Ullensvang, Norway. ⟨hal-00610110⟩