An Image Encryption Algorithm Based on Four Dimensional Hyperchaotic System

Aiming at the problem that the encryption structure of some image encryption algorithms had nothing to do with the plaintext and cannot guarantee the security of the ciphertext image, this paper proposed an image encryption algorithm based on a four-dimensional hyperchaotic system. The initial value of the chaotic system is determined by the SHA256 hash value of the plaintext image and the input parameters, making the algorithm capable of resisting known plaintext attacks and selected plaintext attacks. At the same time, the hash value and input parameters are used to determine the moving step size of the Zigzag scrambling algorithm. The algorithm uses the CFB mode in block ciphers, and updates the chaotic sequence according to the ciphertext, which makes the subscript selection of the Knuth algorithm more random to improve the encryption performance of this algorithm. The experimental results demonstrate the excellent robustness and security of the proposed scheme. It can resist common attack methods such as statistical analysis and differential attacks.