Color image encryption based on hybrid chaotic system and DNA sequences

Stability and complexity of the encryption process besides affordable encryption time are the two challenges of image encryption. In this paper, Chen chaotic system is applied to produce random sequences and using these sequences some arrays are created for image permutation and key stream production. Since these random sequences have two different applications, separate calculation time is not necessary. As a result, time complexity decreases. Each of the color components of the plain image are converted to a one dimensional vector for image permutation and the permutation is performed using the generated chaotic arrays. Created key stream is converted into a chaotic image. Then permutated image and the chaotic image are divided into equal blocks. The plain image blocks are encoded using DNA rules. The encoding rules are chosen randomly using a three-dimensional Logistic map. This process makes it possible to have various options for choosing DNA coding rules. Finally, all the encrypted blocks are combined and the encrypted image is obtained. Experimental results show that the proposed approach has a large key space and is resistant against different attacks. Also, the correlation between the neighboring pixels is decreased and the resulting entropy is very close to ideal.