A compact image encryption system based on Arnold transformation

A novel compact image encryption system is proposed based on Arnold transformation (AT). In general, AT is a pixel-scramble tool in image encryption, but its security is not high enough as an independent cryptosystem because of its periodicity. Hence, extra diffusion operations are needed to diffuse the pixel values to acquire the higher security. Here an encryption algorithm is proposed by AT. Firstly, the corresponding coordinates of each pixel in original image are calculated by AT. Secondly, the pixel values of the two corresponding coordinates are disturbed by another AT. These two processes can diffuse the pixel values of the original image. At last, the diffused image is pixel scrambled by AT with different parameters. This is the confusion process. In proposed scheme, the diffusing and confusing operations are both realized by AT. At the same time, the image is encrypted as a pixel distribution instead of a data stream. The key space, key sensitivity, the correlation, the cost time and the security of proposed cryptosystem are analyzed and the results confirm that the proposed image encryption algorithm demonstrates extraordinary performance.