Double-image encryption based on spatiotemporal chaos and DNA operations

A double-image encryption algorithm combining DNA insertion and deletion operations with spatiotemporal chaos is proposed. The technology of DNA sequence insertion and deletion is employed in both confusion and diffusion to encrypt two images simultaneously. In the proposed image encryption scheme, the key streams to control DNA operations are obtained by means of iterating the system of non-adjacent coupled map lattices (NCML). The original key streams are related to the plain-image, which increases the sensitivity of the proposed algorithm. Two confused images are served as keys to encrypt each other. The confused image is associated with another through the DNA insertion and deletion, which not only improves the security of image encryption system but also enhances the encryption speed. It is demonstrated that the proposed image encryption algorithm has the characteristics of large key space, high sensitivities of key and plain-image, and high entropy. Also, the proposed algorithm is robust to occlusion-attack and noise-attack. Therefore, the proposed double-image encryption algorithm is heuristic for the DNA computing applications into the multi-image encryption.