J.C. Hernández, P. Isasi, and A. Ribagorda (Spain)
Cryptanalysis, Genetic Algorithms, Block ciphers, TEA.
One of the first objectives of a cryptanalyst is to be able
of distinguishing the output of a cryptographic primitive
from the output of a random mapping. This seriously
affects the credibility of the primitive and in many cases
automatically defeats it. In this work, we present a new
cryptanalytic technique, which we show is useful in
distinguishing a block cipher from a random permutation.
This technique is based in the selection of the worst input
patterns for the block cipher with the aid of genetic
algorithms. The objective is to find which input patters
generate a significant deviation of the observed output
from the output we would expect from a random
permutation. This method is applied over the block cipher
TEA reduced to 1 round and some interesting results are