Dynamic Multi-Layered Image Encryption scheme using User Driven Chaotic Sequences

Abstract The paper introduces a novel approach that leverages the unique characteristics of users' authenticated usernames to determine the sequence in which image blocks are encrypted. This methodology employs two key strategies: the utilization of four individual chaotic maps - Sin, Chebyshev, Logistic, and Gaussian - for encryption, and the encryption of image blocks using a novel 4D chaotic map. The process begins with the segmentation of an N×N×3 color image into its red, blue, and green components, each of size N×N. The image components are further subdivided into four arrays, each sized (4×4) × (N/4) × (N/4). Chaotic sequences generated via schemes 1 and 2 aid in the encryption of various image bands, serving as fundamental encryption keys that guide both confusion and diffusion processes. The proposed encryption systems, Scheme 1 and Scheme 2, were rigorously evaluated using extensive simulations and compared to a standard approach. Both methods outperformed against statistical analysis differential attacks, with NPCR and UACI values approaching ideal standards. Notably, Scheme 2, with the proposed 4D map, performed better than Scheme 1, especially with regard to UACI and NPCR. Furthermore, the systems had a large key space, making decryption impossible within an astronomical timeframe. Entropy and correlation analysis validation yielded values consistent with established techniques, whereas pixel distribution analyses confirmed homogeneity in horizontal, vertical, and diagonal directions. The research presents a new encryption approach that takes advantage of user-specific attributes and outperforms standard methods in terms of security and performance.