A Discrete-Time Lorenz-Driven HCCDC Algorithm for Secure and Reversible Color Image Encryption

A robust technique for encrypting color images is introduced in this work, employing a Hybrid Chaotic Confusion-Diffusion (HCCD) strategy combined with a DT Lorenz chaotic model. In fact, the DT Lorenz system is used as a nonlinear key generator to generate ultra-sensitive pseudo-random sequences that exhibit intricate chaotic properties and a wide effective key space. Such sequences are then exploited in the HCCD scheme to carry out effective confusion and diffusion. Extensive simulation results using standard test images prove that the proposed scheme can produce an encrypted image that is almost uncorrelated in adjacent pixels, possesses entropy rates close to the theoretical limit of 8 bits per pixel, and is highly robust against differential attacks. Additionally, the key space is much larger than 2200, making brute-force attacks computationally impossible. Performance analysis of the proposed scheme shows better statistical security against standard AES in terms of image-based metrics. The proposed encryption scheme is computationally efficient and thus can be applied for secure image communication and various multimedia security applications.