An enhanced hybrid chaotic system and its application in image encryption

Abstract

While chaotic systems provide essential confusion and diffusion properties for image encryption through their sensitivity to initial conditions, strong randomness, and excellent ergodicity, existing chaotic encryption schemes suffer from insufficient security due to the relatively simple nonlinear dynamics of traditional chaotic systems. To overcome this critical limitation, this paper proposes a novel enhanced hybrid chaotic system whose parameters are offline-optimized using the Non-dominated Sorting Genetic Algorithm II (NSGA-II). The NSGA-II algorithm performs offline multi-objective optimization to determine optimal chaotic parameters that generate sequences with significantly increased complexity and improved cryptographic properties. The enhanced system is then integrated into an image encryption algorithm employing pixel permutation and diffusion operations. Experimental validation demonstrates superior security performance with correlation coefficients reduced to 0.0001, information entropy reaching 7.9989, and significantly enhanced resistance to statistical attacks.