A novel image encryption scheme based on substitution-permutation network and chaos

•A novel image encryption approach based on SP network and chaos is proposed.•Qualitative and quantitative analysis verify the effectiveness of the proposed encryption scheme.•The encryption scheme shows superior performance than previous schemes.

In this paper, a novel image encryption approach based on permutation-substitution (SP) network and chaotic systems is proposed. It consists of four cryptographic phases: diffusion, substitution, diffusion and permutation. Firstly, a diffusion phase is proposed based on new chaotic map. Then, a substitution phase based on strong S-boxes followed by a diffusion phase based on chaotic logistic map are presented which will, in turn, significantly increase the encryption performance. Finally, a block permutation phase is accomplished by a permutation function to enhance the statistical performance of the proposed encryption approach. Conducted experiments based on various types of differential and statistical analyses show that the proposed encryption approach has high security, sensitivity and speed compared to previous approaches