Chaos-Based Fast Image Encryption Scheme with Double Zigzag Permutation and Secure SHA256

Abstract

Encryption is generally used to protect the content of images. This paper proposes a simple chaos-based color image encryption algorithm with permutation and diffusion stages dependent on the plain image to increase plain text sensitivity by collaboratively leveraging a sampled random noise signal, SHA-256, Henon chaotic map, double zigzag scanning and Lorenz system. Specifically, a hash value of the plain image and a sampled true random noise signal are generated using SHA-256 hash function and considered as an initial one-time key, which is then used to locate values from the sampled true random noise signal array to define the initial values and parameters for chaotic Henon map and Lorenz system. The Henon chaotic map creates an output that defines the starting point for double zigzag pixel scanning in the permutation stage, whereas the Lorenz system generates three sequences to diffuse the image’s three components; red, green, and blue using the XOR operation in order to get an encrypted image. Finally, statistical analysis results are offered to evaluate the complexity and ascertain security functionality for the proposed algorithm. Results show that the proposed image encryption algorithm is superior in comparison to other existing algorithms.