Application of Cellular Automata in Symmetric Key Cryptography

The main concern of this paper is cryptosystems with a symmetric key, in particular block ciphers. The most important components of block ciphers are substitution boxes (S-boxes). Developing methods of cryptanalysis make ciphers worked on classical S-boxes not safe enough. Therefore, we propose a methodology of generation cellular automata (CA)-based S-boxes with enhanced quality. We provide an exhaustive experimental analysis of the proposed CA-based S-boxes in terms of non-linearity, autocorrelation, balance and strict avalanche criterion. We show that proposed S-boxes have high cryptographic quality. The interesting feature of the proposed S-boxes is a dynamic flexible structure, fully functionally realized by CA, while the classical S-boxes are represented by fixed table structures.