A dual image encryption method based on improved Henon mapping and improved Logistic mapping

In this paper, an improved two-dimensional Henon mapping model and an improved one-dimensional Logistic mapping model are designed. By analyzing the bifurcation diagram, chaotic orbit, Lyapunov index and approximate entropy of the improved chaotic mapping model, it is concluded that the two improved chaotic mapping models have better ergodicity and higher chaos complexity, and are more suitable for designing secure cryptosystems. Aiming at the problem that the security of encryption system will be reduced if the key is reused, this paper designs a new key generation method using Chebyshev mapping and plaintext image. Using the improved chaotic mapping model, a new image encryption method is designed in this paper. First, we divided the two images to be encrypted into 8-bit planes respectively, and Zigzag transformation was performed on each bit plane. Then, we index the 16-bit planes of the two images into a 4*4 two-dimensional matrix, perform Zigzag transformation, and combine the scrambled bit plane sequence into two intermediate images in turn. We then use the key generator designed in this article to generate the key. Finally, we apply the two intermediate images to the improved Henon mapping and the improved Logistic mapping respectively for diffusion to form two ciphertext images. The experimental results show that this method has a large scrambling range, random diffusion mode, high security and good image encryption effect, and has strong resistance to common attacks, and is easy to implement.