Multi-Granularity Reversible Cellular Automata Applied in Data Encryption

Cellular automata has been considered as a prospective direction in cryptography. In order to overcome some shortcomings in traditional researches in cellular automata (CA), a multi-granularity cellular automata (MGCA) is introduced. Combining MGCA with reversible CA (RCA), a cryptography algorithm is proposed. In the algorithm, extended RCA, which has many iteration rules, provides enough great secret-key space. Furthermore, in order to improve the complexity of CA's dynamics, all cells adjust their granularity dynamically by "split-recombination" during the process of encryption and decryption. Based on it, the algorithm achieves a high speed of encryption and decryption. The analysis results show that the cryptosystem can resist brute attack and differential attack, and also has high security. The hardware that shared by encryption and decryption caused the cryptosystem has a strong practicability.