Image Encryption Algorithm Based on Bit-Level Permutation and Dynamic Overlap Diffusion

In order to guarantee the security of digital images, image encryption is a good tool. This article puts forward a novel image encryption/decryption algorithm based on bit-level permutation and dynamic overlap diffusion. Firstly, location information set by users is used to scramble the plain image in the bit-level, changing the pixel position of the image while changing the pixel value. Then, using the plaintext related method to control the iteration parameters of Arnold transform. These two parts together form the permutation process of the algorithm. Thirdly, the overlap steps are set according to the encryption security requirements, and dynamic overlap diffusion is performed on the permutation image. At the same time, the plaintext information entropy and variance are used to update the diffusion key in the five-dimensional hyperchaotic system to achieve the plaintext correlation of the encryption key. Arnold transform and dynamic overlap diffusion can ensure that different key streams are generated when encrypting different images. Finally, experimental analysis and numerical simulation show that our algorithm has high efficiency, high security, high sensitivity, and can effectively resist various attacks.