Color image encryption algorithm with realitypreserving fractional discrete cosine transform and spatiotemporal chaotic mapping

A color image encryption scheme is proposed based on a reality-preserving fractional discrete cosine transform (RPFrDCT) and spatiotemporal chaotic mapping. The scrambling and diffusion operations are carried out after the RPFrDCT and make three components of image affect each other. The main advantages of this scheme are the real-valued output, the nonlinear manipulation, the high sensitiveness and high robustness to the cipher keys. Experimental results demonstrate that the proposed encryption scheme is feasible and effective.