Design and analysis of variable-length block encryption algorithm based on Chaos Particle Swarm

In this paper, a Chaos Particle Swarm (CPS) algorithm is proposed which fuses sensitivity to initial value, randomness and ergodicity of chaos into conventional particle swarm. Chaotic discrete mapping uses CPS to carry out variable-length block encryption to enhance complexity and unpredictability of cipher text. Experiments illustrated that it is difficult to decrypt cipher text in this algorithm through statistics analysis, and this algorithm can resist the attack of differential characteristics. Moreover, the length of the text remains no change before and after encryption, and the method can be used to extend other cipher algorithms.