On the Applicability of the Chi-Square Statistic in the Problem of Determining the Parameters of Block Encryption Algorithms

This article presents the results of practical application of statistical methods for analyzing block encryption algorithms operating in the ECB mode. In particular, in cases of incorrect use of plaintext encryption algorithms, it is shown that it is possible to determine the block size of the encryption algorithm based on the analysis of the chi-square statistics computed from the available ciphertext volume.