Design of a novel image block encryption algorithm based on chaotic systems

In this paper, a novel image block encryption algorithm based on three-dimensional Chen chaotic dynamical system is proposed. The algorithm works on 32-bit image blocks with a 192-bit secret key. The main idea is that the key is employed to drive the Chen's system to generate a chaotic sequence that is inputted to a specially designed function G, in which we use new 8 × 8 S-boxes generated by chaotic maps in [14]. Function G is iteratively performed several times and its last outputs serve as the keystreams to encrypt the original image block. The design of the encryption algorithm is described in detail, along with the security analyses including key space analysis, correlation analysis of two adjacent pixels and analysis of diffusion and confusion. The results indicate that the proposed algorithm has some good desirable cryptography properties and it can be easily used to realize the security cryptosystems over the Internet.