A new image encryption method based on a 6D hyperchaotic map and genetic operators

Abstract

This paper presents a novel and secure image encryption method. The plain image’s pixels are confused using the N-point crossover operation of genetic algorithms. Randomly paired rows and columns are determined by the two state variables of a six-dimensional hyperchaotic map. The number of crossover points, which are calculated by the two other state variables of the hyperchaotic map, differ from each other for each row or column pair. The crossover positions are specified according to the number of crossover points with the help of the last two state variables. The proposed algorithm generates the diffusion stage’s encryption key using the SHA-256 hash value of the plain image. Mutation and crossover operators are implemented into the 16-bit subblocks of the 256-bit hash value. Thus, a total of 16 subblocks with the size of 16 bits are employed as the encryption key after the implementation of the genetic operations. The scrambled image’s pixels are altered with the generated encryption key and previously encrypted pixels. Key space and sensitivity, histogram, correlation, information entropy, differential, data loss, noise attack, and computational time analyzes are performed to test the safety and effectiveness of the encryption method. The experiments and simulation results show that the proposed encryption technique is highly secure and efficient since it can resist various attacks. The comparisons with recent works show that this method outperforms many state-of-the-art algorithms in several performance metrics.