A novel encryption scheme for colored image based on high level chaotic maps

摘要

In the following paper, the novel method for color image encryption has proposed based on high level chaotic maps . We introduced two novel chaotic maps "Cosinus-Arcsinus (CA)" and "Sinus-Power Logistic (SPL)", which have better chaotic behaviour against other available chaotic maps. Our scheme like other image encryption schemes has two main phases, which are pixel shuffling and pixel diffusion. We made an efficient chaotic permutation method, which is extremely dependent on plain image. The proposed method compared with other availabale permutation methods in pixel shuffling stage has a better performance with a lower computational overhead. Another advantage of our permutation method is less correlation between adjacent pixels in the permuted image, which causes high confusion levels with lower iterations. In pixel diffusion phase, we introduced coupled map based on SPL map to change each color component distinctly. Moreover, we used CA map to generate three chaotic sequences for deriving initial seeds of coupled map in a random manner. Followed by three chaotic matrix will be created to change pixels color component values. The proposed diffusion phase implies desirable uniformly distributation in color histogram of encrypted image and makes the scheme robust against statistical attacks. In addition, creating secret keys in a large size and high sensitivity to the original pictures leads acceptable results in the average of NPCR (99.67), UACI (33.45), and resistance against brute-force attack. The experimental results reveal that the new image encryption scheme has the charectristics of 'secure encryption algorithm' such as, large key space, high security and high sensitivity.