Topology-Evolving Image Encryption Algorithm Utilizing 2D Rosenbrock–Schwefel Hyperchaotic Map

Abstract

Traditional image encryption methods based on static permutation and diffusion are vulnerable to structural cryptanalysis and usually show limited resistance to channel interference. To address these problems, this paper proposes a robust topology-evolving image encryption algorithm for secure visual data transmission. The main contribution is a bidirectional oscillatory spatial permutation mechanism governed by a dynamic linked list topology. Unlike fixed-path scrambling, the proposed structure evolves continuously with the system state during image traversal, thereby increasing nonlinear path complexity and improving resistance to structural attacks. A plaintext-dependent adaptive diffusion mechanism is further designed to produce a strong global avalanche effect. In addition, a two-dimensional Rosenbrock-Schwefel hyperchaotic map is constructed to generate high-quality pseudorandom sequences for permutation and diffusion. Experimental results show that the encrypted images achieve a near-ideal information entropy of 7.9994, while the number of pixels change rate and unified average changing intensity reach 99.6076% and 33.4683%, respectively. The method also maintains good recovery performance under data cropping and noise interference, demonstrating its potential for secure image transmission in complex communication environments.