Resistance of a CAST-Like Encryption Algorithm to Linear and Differential Cryptanalysis

Linear cryptanalysis and diierential cryptanalysis are two recently introduced, powerful methodologies for attacking private-key block ciphers. In this paper, we examine the application of these two cryptanalysis techniques to a CAST-like encryption algorithm based on randomly generated s-boxes. It is shown that, when randomly generated substitution boxes (s-boxes) are used in a CAST-like algorithm, the resulting cipher is resistant to both the linear attack and the diierential attack.