An Efficient Image Encryption Scheme Based on Four Directional Diffusion and Regular Key Selections
At present, many existing chaos-based scrambling-diffusion encryption techniques already have a relatively high level of security. However, most of them leverage fixed keys to change the pixel positions and complete encryption from a single direction, resulting in poor randomness of the ciphertext. To solve this problem, this paper proposes an image encryption scheme based on four directional diffusion and regular key selections. Firstly, the initial values of four logistic maps are generated with a 128-bit external key, and an iterative process is performed to obtain a group of secret keys as candidates for the subsequent key selections. Then, during the pixel scrambling process, the plaintext pixels from different positions are scrambled with different keys according to the predefined rules. Finally, a four-directional continuous diffusion method is designed to encrypt the scrambled image. The experiment results confirm that the proposed scheme has a high level of security and feasibility. The ciphertext correlation test, maximum deviation analysis, irregular deviation analysis and sensitivity test show that the proposed scheme is superior to the state-of-the-art methods in many
Keywords: scrambling-diffusion, chaotic encryption technique, image encryption, logistic map, ciphertext correlation, sensitivity
J. Yang, S. Xuan, H. Chen and X. Li, "An Efficient Image Encryption Scheme Based on Four Directional Diffusion and Regular Key Selections", Engineering Intelligent Systems, vol. 30 no. 3, pp. 175-183, 2022.