Exploiting plaintext-related mechanism for secure color image encryption

Nowadays, many image cryptosystems have been cracked by chosen-plaintext attacks, for they are not highly sensitive to plain image. To solve this problem, we introduce a plaintext-related mechanism for secure color image encryption, and it is established in the generation and selection of chaotic sequences, permutation and diffusion. In the proposed image cryptosystem, the architecture of permutation and diffusion is adopted. Firstly, plaintext-related Latin-square-based block permutation is proposed to randomly shuffle pixels of the color plain image, diffusion method dependent on the plaintext and scrambled image is further given to modify pixels of permutated image, and finally cipher image is gotten. The chaotic sequence for diffusing the current pixel is dynamically generated according to the plain image and scrambled image, and diffusion operations of red, green and blue components of color plain image affect each other. Besides, chaotic sequences used in encryption are produced by new one-dimensional chaotic systems and dynamically selected, and initial values of chaotic systems are computed by plain image and external keys. Experimental results and security analyses demonstrate that our image encryption has large key space and high security level, and it can be applied for the secure communication of image information.