Encryption Research, The Dsp-based Spatiotemporal Chaos

Chaos is generated by certain nonlinear-system, and it is similar to random movement. Researches show that chaotic systems have characteristics of ergodic property, non-periodicity and quasi-randomicity, so chaotic systems fit for information encryption. But many schemes proposed are all based on low dimensional systems, which having low secrecy and existing the dangers to be broken by reconstructing systems. Furthermore these schemes are lack of necessary security analysis. The high dimensional chaotic systems (such as spatiotemporal chaotic system) have lots of parameters, and are sensitive to boundary conditions and the initial values of the systems. The systems have large key-spaces, so they have good application foreground than low dimensional chaotic systems in information encryption.Two encryption schemes based on spatiotemporal chaotic system are proposed in this paper. (1) Chaotic stream cipher scheme: good binary sequences are generated using chaotic system, and after performance tests the sequences are applied to encrypt images and speech signals. (2) Chaotic block cipher scheme: this scheme combines spatiotemporal chaos and blowfish arithmetic together. The P and S-box are generated using on two-way coupled map lattice system, without depending on blowfish cycles. This scheme has stronger anti-attack ability than traditional block cipher such as DES.DSP adopts Harvard structure in which program memory and data memory are divided. DSP can realize various digital signal process algorithms by special hardware multiplier. In this paper DSP chip is used as information encryption platform. Two information encryption schemes above are achieved based on DSP for its powerful signal process ability. Satisfied results and real time performance are achieved, which indicates the wide development foreground of spatiotemporal chaotic systems and DSP technology in information encryption.