An Efficient Chaotic Image Cryptosystem Based on Simultaneous Permutation and Diffusion Operations

Recently, several multimedia encryption techniques with permutation-diffusion architecture have been developed. The traditional architecture applies the diffusion and permutation functions as two separate phases. This separable design enables the attacker to launch several forms of attacks in addition to the degradation of the encryption speed. Furthermore, during the diffusion phase, the image pixels are masked in a static order, which may expose significant information about the encryption technique to the attacker. Accordingly, to remedy these problems, this paper suggests an efficient image cryptosystem based on simultaneous permutation and diffusion functions that process the image pixels in a dynamic order fashion. Specifically, the proposed method employs the Chebyshev-Chebyshev map to horizontally and vertically mix the plain-image information. Then, it utilizes the modified Logistic map to mask the image pixels and shuffle the masked values simultaneously. Meanwhile, the control parameters of the employed chaos systems are directly correlated to the plain-image to assure that different key-streams are created for distinct plain-images. Simulation results and security scrutiny confirm that the suggested cipher has several brilliant characteristics, including the robustness against various types of attacks.