An improved method for image encryption based on high level chaotic maps and improved gravity model

Abstract

Image encryption field has motivated many researchers, recently and too many studies held by them. We propose a high dependency method the original image and parameter G. Moreover, we use a new simple chaotic map with bigger Lyapunov exponents and so stronger chaotic behaviour, against which one used by Xing-yuan Wang et al, in diffusion phase. In permutation phase, known chaotic map “Cross map”, used for pixel shuffling. The proposed diffusion phase implies desirable uniformly distributation in color histogram of encrypted image and makes the scheme robust against statistical attacks. Furthermore, creating secret keys in a large size and high sensitivity to the original image leads to acceptable results in the average of NPCR (99.67), UACI (33.50), and resistance against brute-force attack. The experimental results prove that the image encryption scheme has the characteristics of secure encryption algorithm such as, large key space, high security and high sensitivity.