Research And Implementation Of Block Cryptography S-Boxes Based On Chaos

S box is the only nonlinear component in many block cipher, whose strength determines the security of cryptography algorithm, and whose speed determines the scrambling speed of the whole algorithm. Therefore, a good S box plays an important role on enforcing the security of the Feistel structure, SPN structure and IDEA cryptography algorithm. The development of the chaos theory brings new ideas to the research of S box. Because of the advanced characteristics of the chaos system, construction of a S box based on the chaos system is becoming a hot subject in the academic circle.This thesis makes an in-depth study and research of S box based on Chaos. After analyzing the construction methods of S box based on chaos and studying the system of Chaos. In this paper, we propose a new S box scheme based on chaos through iterativing chaotic map and displacing initia table several times.and we analyse the nonlinear and differential uniformity of the S box. The results show that the differential uniformity of the S box we proposed is better than the existing S box based on chaos, which has strong abilities on resisting differential attacks and nonlinear attacks. According to the above research, I designed the system with dynamic S boxes based on Spatiotemporal Chaos and an image encryption test was proposed with the system. The great cryptographic properties of the S box were analysised and the scheme is reasonable and feasible which was proved by image encryption experimente.