Combined Interleaved Pattern to Improve Confusion-Diffusion Image Encryption Based on Hyperchaotic System

Abstract

The quality of encryption is dependent on the complexity of the confusion-diffusion pattern and the quality of the keystream employed. To enhance complexity and randomness, this study proposes a combination of multiple interleaved patterns, including Zigzag, Hilbert, and Morton patterns to complicate the confusion-diffusion. The keystream is generated from the improved logistic map and the 6D hyperchaotic map, which complement each other due to their sensitivity to initial conditions and control parameters. This produces highly random and nonlinear keystreams, making them difficult to predict. The encryption process consists of four phases, alternating between diffusion and confusion. Furthermore, SHA-512 is used to enhance key space and sensitivity. Based on the test results, the proposed encryption technique can withstand various attacks, such as statistics, differential, brute force, and NIST randomness tests, as well as data loss and noise attacks. Most of the results are better than previous studies.