Utilization of Statistical Methods in Cryptanalysis of Combinations of Classical Ciphers and Their Implementation in the Python Programming Language

This work focuses on the research and implementation of statistical methods in the field of cryptanalysis, with an emphasis on the analysis and decryption of ciphers that utilize combinations of classical substitution and transposition ciphers. The first part introduces the theoretical foundation of cryptanalysis, applicable to the principles of substitution and transposition ciphers. Subsequently, specific statistical methods are examined, including frequency analysis, Kasiski's method, and Friedman's index of coincidence for estimating the key length. To address the combination of ciphers, methods based on maximum likelihood and Markov chains are employed. The conclusion of the work is dedicated to implementing these methods in the Python programming language and evaluating the results. The contribution of the work lies in focusing on the use of statistical methods for combinations of ciphers, a topic not directly addressed in standard literature.