Security Evaluation of Cryptosystems based on Orthogonal Transformation

Abstract

Proposed approach for security evaluation of some cipher systems based on orthogonal transformation is introduced in this paper. This approach based on using the Discrete Fourier transform (DFT) as a main processor in the evaluation process. The mean value of the DFT coefficients of the ciphered outputs is considered as an evaluation parameter for evaluating the security of the considered cipher system. This approach was tested on symmetric and asymmetric cryptosystems. For symmetric one, we choose a stream cipher system to be tested by this method. While for a symmetric one we chose the RSA (public key cryptosystem). These different choices gave a wide spread use for this proposed method in comparison with other evaluation methods. The results were encouraging, and can be considered as a suitable approach to enhance the security evaluation tasks. That is really considered as a hard problem facing the cryptosystem design.