On symmetric color image encryption system with permutation-diffusion simultaneous operation

摘要

In the traditional image encryption systems, the permutation-diffusion operation is often conducted in two essentially separable or independent steps, which appears not only to be inefficient but also vulnerable in being attacked since each step can be targeted separately. In this paper, we propose a new plaintext-related cryptosystern in which the permutation-diffusion operation is performed in a simultaneous manner. More specifically, the simultaneous permutation-diffusion operation (PDSO) leads to the confusion and diffusion interacted each other, and thus generates better security level as well as higher efficiency of encryption process. The proposed encryption scheme only requires a single PDSO in the corresponding encryption process, in which the first encrypted pixel's position in cipher image is randomly chosen and its value is determined by both pixels in the original image and the elements in key-streams obtained by three one-dimensional chaotic mappings, and the current encrypting pixel's value is set to be associated with the previous encrypted pixel. Under our framework, the proposed encryption scheme is highly sensitive to minor differences in both secret key and plain image, resulting in resisting chosen/known plaintext attacks effectively. Simulation results show that the proposed scheme demonstrates excellent security capacity with high efficiency, comparing with existing approaches in literature.