Improved Pixel and Bit Confusion-Diffusion Based on Mixed Chaos and Hash Operation for Image Encryption

Confusion and diffusion are two main concepts in cryptography that affect the quality of encryption and resistance to various attacks. Both of these concepts are influenced by the quality of the keystream used. Keystream generation needs to involve plain images as one way to bind sensitivity to plain images. But when it involves plain images directly, encryption security has negative side effects. So this research proposes to perform a diffusion operation with a logistic map on a plain image before generating the keystream. Not only using one keystream, the proposed method also uses three other keystreams and Arnold transform whose input parameters are processed by hash operations. Two keystreams are generated using the four-dimensional Lorenz system for the permutation of column and row image pixels. Next, sixteen Arnold transforms with different parameters are used for bit permutation. The last keystream is generated with a Henon map to carry out the diffusion stage two so that a cipher image is produced. Based on the testing results, the proposed method has satisfactory encryption results that are resistant to various attacks, especially brute force, statistical, and differential attacks.