Design of secure cryptosystem based on chaotic components and AES S-Box

Abstract

In this paper, we design, realize and evaluate a new secure cryptosystem based on a Pseudo-Chaotic Number Generator(PCNG), a global diffusion and a block cipher in Cipher Block Chaining(CBC) mode. The proposed PCNG, defined over a finite field, is based on a discrete Chebyshev map coupled with a Pseudo-Random Number Generator(PRNG) and a discrete skew tent map. Our PCNG can remove a hidden danger of deteriorated security caused by the dynamical degradation encountered in numerical implementation of chaotic maps defined on real numbers. The global diffusion uses a Horizontal Addition Diffusion(HAD) and a Vertical Addition Diffusion(VAD) followed by a modified 2-D cat map. The block cipher in CBC mode is based on a confusion layer using the AES S-Box, followed by a diffusion layer built on the modified 2-D cat map and a key addition operation. The global diffusion enhances the diffusion process of the block cipher. Conducted security analysis and the obtained results have proven that the proposed cryptosystem design is robust with high security and that it can be applied to practical implementations.