Color image DNA encryption using NCA map-based CML and one-time keys

In this paper, we introduce a novel color image encryption algorithm based on DNA sequence operations, one-time keys and the spatiotemporal chaos. Firstly, the key streams are generated by the NCA map-based CML, where the hash function SHA-256 is used to update the system parameters and initial conditions combining with the plain-image and the secret keys. Secondly, decompose the plain-image into the red, green, blue components, and convert them randomly into three DNA matrices by the DNA encoding rules. Further, combine three DNA matrices into a new DNA matrix, and then perform the row-wise and column-wise permutations on it. Thirdly, divide the shuffled DNA matrix into three equal blocks and implement the DNA addition, subtraction and XOR operations on these DNA blocks. Finally, transform the DNA matrices into the decimal matrices separately according to the DNA decoding rules. To enhance the security of the cryptosystem, a diffusion process is further carried out by using the key streams. Thus, the resulting cipher-image is attained. Experimental results and security analysis show that the presented encryption algorithm has a good encryption effect and can resist various typical attacks.