Research Of Several Image Encryption Based On Chaotic Systems

In recent years, along with the development of the computer network communication technology and the multimedia technology, human society has entered into the digital age. Due to the characteristics of strong data visual and large amount of information, the multimedia has become the important method of taking use of information in human society. Especially, the digital image can contain more information than the voice and character, plays a decisive role in multimedia information, and so the requirement to transport the digital information by network safely has been more and more urgent.The characteristics of the chaotic system, such as well pseudorandom, long inscrutability, high sensibility to the initial value, make it be applied in the code field. This paper introduces Chaos and the knowledge of cryptography firstly, and then proposes three kinds of image encryption algorithm based on the analysis of image encryption algorithm which has been based on the chaos theory. In this paper, we propose a novel algorithm for image encryption based on couple chaotic systems, which improve the phenomenon of degradation dynamics of chaotic systems in the limited accuracy through the cascade of high-dimensional space-time chaotic systems. We combine the above algorithm with selective image encryption and propose a selective image encryption based on couple chaotic systems. Then, a chaotic image encryption algorithm combined of the stream cipher and the block cipher has proposed through the analysis of the advantages and disadvantages of the existing stream cipher and block cipher. The theory analysis and numerical experiment can both verify that these algorithms can hit the target of confusion and diffusion requested by the cryptography and can effectively prevent differential attacks.