On intermediate evaluation of block ciphers
[ 1 ] Instytut Automatyki i Inżynierii Informatycznej, Wydział Elektryczny, Politechnika Poznańska | [ P ] employee
2007
paper
english
EN In the paper an intermediate evaluation of block ciphers method is presented. As a criterion of quality, probability of the best nonzero linear approximation is taken. The main idea of the method is to restrict considerations to only two types of approximations: zero and nonzero. For a cipher graph G of zero-nonzero approximations is constructed. Algorithm SP calculates the shortest path of a specified length in graph G. This path determines the best zero-nonzero approximation of the cipher, that fulfils approximation conditions. The method is quite general but it is not independent of the structure of a cipher. In the paper the method is presented for DES.
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