2007 , Volume 12, № 2, p.122-129

In this paper we present a statistical analysis of all block ciphers, which were AES (Advanced Encryption Standard) candidates. AES competition was organized by the US National Institute of Standards and Technology. With the help of the ``Bookstack'' test it is for the first time experimentally shown that a cipher text does not have a uniform distribution after 8 MARS rounds. It is experimentally ascertained that the FROG and LOKI97 ciphertexts can be distinguished from the uniform distribution after half of all rounds. We build a forecast that says that FROG and LOKI97 require 2⁷⁸ and 2⁸⁶ blocks respectively to distinguish a ciphertext from the uniform distribution after the full number of rounds.