Information theoretic approach for decipherment problems is the recent trend in cryptanalysis. The behavioral transformation of message units is addressed upto certain extent in the encryption process. However the amount of confusion and diffusion in terms of statistical distribution parameters between message and cipher text is a point of interest for cryptanalyst. In the present work we addressed this issue with the help of enhanced probability distribution function. The basic units of any message text are observed to be heuristic in nature depending on the sample. Averaging function is adopted while evaluating the enhanced probabilities of message units. The retrieved efficiency of cipher text only attack on samples of English, Hindi Telugu, Kannada is presented in this paper.

In this paper presents the Linear Cryptanalysis on S-DES and Symmetric Block Ciphers Using Hill Cipher Method. As a vehicle of demonstration of this concept, choose simple yet representative block ciphers such as computationally tractable versions of S-DES, for the studies. The attack presented in this paper is applicable to block structure independently of the key scheduling. The attack needs distinct known plaintexts which are a more realistic attack model in comparison with impossible differential cryptanalysis which uses chosen plaintext pairs. Moreover, linear cryptanalysis on simplified data encryption standard performed simulations on a small variant block and present the experimental results on the theoretical model of the multidimensional linear cryptanalysis using Hill Cipher method.