Research And Analysis On Self-adaptive And Parallel Image Encryption Algorithms In Spatial Domain

With the rapid development of computational ability and network technology, multimedia information has been extensively applied to various fields. Multimedia information such as audio and video information is transmitted through networks. During the transmission, the multimedia information may be leaked and even modified. Therefore, how to ensure the security of multimedia information has become an important issue. The cryptographic technology is a major method to solve this problem efficiently. This paper focuses on how to design a secure, fast, easily-operating encryption algorithm for digital color images in spatial domain. The contribution of this paper is listed as follows.①A brief description of the basic theory for image encryption in spatial domain, including basic theory of cryptology technology and image encryption, performance criteria, diffusion techniques is presented.②A basic requirement for parallel image encryption methods is introduced, and some advantages and disadvantages of the existing parallel image encryption algorithms are given.③A new self-adaptive algorithm to encrypt color images is given by combining the A transformation, the M transformation, the S transformation and the self-adaptive encryption algorithm.④A modified M transformation is proposed to make the diffusion more efficient. First, a sub-key which is used for the A transformation is generated. Then the whole image is divided to several blocks with 4×4 pixels. The A transformation, the M transformation and the S transformation are applied to each block for the confusion and diffusion. Finally, the self-selective algorithm is used to scramble pixels by using the three components of color images themselves. Repeat the above procedures for several times. Theoretical analysis and simulated experiment have demonstrated the simplicity, the high speed of the proposed algorithm. Moreover, the proposed algorithm can be applied in the actual parallel computational platforms with high security.Finally, some conclusions of this dissertation are given. Some further research directions are given as well.