A newly image encryption scheme based on 3-D coupled map lattice and Baker map

Abstract Recently, image encryption is becoming increasingly important, many chaotic models have been prevalently used to design kinds of cryptographic schemes in chaos cryptography. Among those models, coupled map lattice (CML), as a classics spatiotemporal chaotic model with good performance, is popularly used for those chaos-based cryptographic schemes. However, there exist no scientific studies in the three dimensional (3D) CML model from the view of theoretical and application perspectives besides our previous research. To further improve the complicated chaotic dynamic behavior and extend the application scenarios of CML into a3D CML one, therefore it is introduced into our paper for constructing chaos-based image encryption scheme with higher security. First of all, properties of 3D CML are comprehensively analyzed to fully verify that it possesses more complicated chaotic behavior than one dimensional and two dimensional CML. Subsequently, the chaotic sequences are produced by means of intercepting 32 bit from each node of the 3D CML model, both NIST and TestU01 testing certificate those chaotic sequences have high randomness, which are pretty suitable for designing the chaos-based cryptographic scheme. Based on those above-mentioned analyses, a new color image encryption scheme is proposed via diffusion and confusion. In our scheme, diffusion is performed based on those above-mentioned chaotic sequences via the 3D CML model, while confusion is carried out according to the Baker map. Specially, before diffusion and confusion operations, red, green and blue channel of a plain color image are combined into one pixel including 24 bit (0 or 1) for improving the efficiency of our scheme. To sum up, all corresponding simulations show our scheme has excellent encryption performance, and it would be popularly applied in the real-life cryptographic domains. Our research contributes to enriching the theoretical research on chaotic cryptography and provides new chaotic image encryption schemes.