An Image Cryptosystem based on Diffusion of Significant Bit-planes of a Scrambled Image with Generated Binary Key Matrices

In this paper, the authors have proposed an image cryptosystem for protecting the confidential image data with a high level of security. The encryption algorithm is developed into two phases where in the first phase, the secret image data set is scrambled or shuffled based on the Arnold's cat map and in the second phase the scrambled image is diffused further to enhance the security level. The diffusion process is carried out on selected significant bit-planes of the scrambled image. In diffusion process, we have used a number of binary key matrices of the same size of scrambled image. The binary key matrices are generated based on different SCAN methodology. The experimental results show that the proposed scheme can effectively encrypt the secret image as a random manner. In addition, the proposed scheme provides satisfactory results in terms of Histogram analysis, PSNR, adjacent pixel correlation and entropy. Overall, the proposed scheme is suitable for transmission of the secret image data in highly secure way.