| The dissertation makes the joint of two paradigms: by one side, cellular automata as theoretical computability model and, by the other one, classical cipher systems with bit streams (Vernam ciphers) and with blocks of bits (Feistel networks). Final products will be classical ciphers integrating cellular automata with reasonable levels of security. First step is to design a criterion for the analysis of number-codified cellular automata additive rules and obtain a data base of automata with aleatory appearance. The criterion was a set of aleatority test, and three additional measures: Hamming distance, entropy of configuration and temporal entropy. Second step is to integrate cellular automata in Vernam ciphers making statistical cryptoanalysis and finding ciphers with capacity to pass it. Literature shows a result to stablish that cellular automata and linear feedback shift register are isomorphic and Berlekamp-Massey algorithm could break the cipher. We propose standard solutions to prevent it like clock control and others. Third step is to integrate cellular automata in a Feistel network DES-inspired changing S-boxes by one cellular automata, using internal subkeys data-fixed, and making statistical cryptoanalysis. In addition, we propose the integration of several cellular automata developing the formal scheme to avoid it, and the integration of cellular automata in unbalanced Feistel network too. |
