A Study of Different Complexity Evaluation Approaches for Some Cryptosystems


This paper provides analysis for different approaches used for security evaluation of some cipher systems. Many tests (computational complexity, statistical and Information theoretical ) are performed on the ciphered outputs of a number of classical cipher systems ranging from mono-alphabetic, to poly-alphabetic. The results were encouraging, and can be considered as an approach to enhance the security evaluation tasks (especially for the used skewness , kurtosis, unicity distance and the Key Entropy parameters), that is really considered as a hard problem facing the cryptosystem design.