A new algorithm for image encryption based on couple chaotic system and cellular automata

This paper proposes a novel image encryption algorithm based on couple chaotic system and couple toggle cellular automata. We construct a couple chaotic system which achieves a better cryptographic performance than general chaotic system due to its much larger key space and more complex dynamical characteristics. In our cryptosystem, we also establish couple toggle cellular automata to encrypt image in a parallel fashion. Firstly, plain image is separated into two symmetric parts and pre-processed using couple chaos system, and subsequently encrypted by the couple cellular automata system. Due to the inherent properties of couple chaotic system and couple toggle cellular automata, our approach significantly improves the process efficiency and expands key space compared with similar types of methods. The experimental results and theoretical analysis show that the cryptosystem has a sufficient large key space and satisfies requirements of avalanche effect, thus resisting the brute attack and differential attack effectively.