Collective Behavior of Rules for Cellular Automata-based Stream Ciphers

The problem of generation by cellular automata of high quality pseudorandom sequences useful in cryptography is considered in the paper. For this purpose one dimensional nonuniform cellular automata is considered. The quality of pseudorandom sequences generated by cellular automata depends on collective behavior of rules assigned to cellular automata cells. Genetic algorithm is used to find suitable rules from predefined earlier set of rules. It has been shown that genetic algorithm eliminates bad subsets of rules and founds subsets of rules, which provide high quality pseudorandom sequences. These sequences are suitable for symmetric key cryptography and can be used in different cryptographic modules.