An image encryption algorithm based on Fibonacci Q-matrix and genetic algorithm

In this paper, an image encryption algorithm based on Fibonacci Q-matrix and genetic algorithm is proposed. The new four-layer encryption framework of diffusion-scrambling-diffusion-optimization is adopted. Firstly, an improved four-direction diffusion operation is performed on the original image to achieve efficient global diffusion based on row and column vectors and the first-round diffusion matrix is obtained. Secondly, using the Logistic chaotic system to improve the Josephus scrambling, and then use the improved scrambling method to scramble the first-round diffusion matrix, which improves the scrambling effect of the algorithm. Thirdly, the scrambling matrix is divided into blocks, and then the Fibonacci Q-matrix corresponding to each block is dynamically selected by random numbers and the two are rapidly diffused, which further improves the diffusion effect. Finally, in order to make the optimization more targeted, the initial population is generated by the second-round diffusion matrix and the fitness function is selected according to the correlation of the second-round diffusion matrix. In the optimization process, multiple rounds of selection, crossover and fitness calculation are performed on the initial population to obtain the encrypted image. In addition, the initial values of the NHS hyperchaotic system used in the improved four-way diffusion and the Logistic chaotic system used in the improved Josephus scrambling is all generated from the 256-bit hash values of the original image, which makes the proposed algorithm highly sensitive to plaintext image. The experimental results and security analyses show that the algorithm not only has high security but also has certain robustness and real-time performance, which is suitable for practical applications.