Abstract:

 The merits and drawbacks of digital chaos and cellular automata used in cryptology were represented. On the basis of the analysis on the nonlinear features of 1-D cellular automata rules which have three neighbors  and periodic boundary, a method to design one-way hash function based on cellular automata dynamic parameters was proposed by considering the advantages of the cellular automata and the traditional one-way hash function together. In the iterative structure of MD5 algorithm, the output of the last iterative step was evolved only once according rule 198, and was used as the iterative parameter during the next iterative step, and the quadratic diffusion of the plaintext was implemented. A hash value with a  length of 128 bits was obtained as a result. It is shown that the proposed algorithm can resist differential cryptanalysis and linear cryptanalysis, and is sensitive to the initial message comparatively also. The confusion and diffusion properties of the proposed algorithm are pretty good. Moreover, it is easy to implement this algorithm under any platform by software and hardware. The practicability of the proposed algorithm is better.

Key words: cellular automata, rule 198, dynamic parameters, oneway hash function