Research On Image Encryption Algorithms Based On Chaotic Systems

With the development of the technique of the network and the communication, especially the rise of the electron business affairs, the requirement of the encryption of the information is much higher. The encryption of the image and the sound is much more important. The algorithm of the encryption about the text-data which has good effect is not suitable to the encryption of the image because the data of the image is two-dimension. A lot of algorithms about the image encryption are proposed in order to conform to the characteristic of the image-data and enhance the safety and the efficiency of the image encryption. Among the algorithms, the image encryption algorithms based on chaos are with good encryption performances.The chaotic system is nonlinear dynamic system with high complications. It is very sensitive to the chaotic parameters and the initial conditions. The chaotic successions created by the chaotic system are with non-period and similar randomness characteristics. As a result, the system can be used in the field of communication maintain secrecy. It is also adapt to the image encryptions.Firstly, the fundamental conceptions and the related knowledge of the chaos are introduced in the paper systematically. Secondly, the ways and the requirements of the image encryption are suggested. Finally, the important researches on the algorithms of the image encryption are done according to the superiority of the chaotic on image encryption. The achievements are as follows:A new chaotic image encryption algorithm which both shuffles the positions and changes the grey values of the image pixels is proposed in the paper. The parameters which are link to the plaintext are designed. Firstly, the general Arnold map is used to shuffle the positions of the plaintext. Then the key stream generated by the coupled chaotic maps is adopted to change the pixels of the shuffled image. The experimental results show that the algorithm is not only with large key space but also with a very strong sensitivity to the keys and the plaintext. It is with a perfect statistical property. And it is with the characteristic of resisting the known-plaintext attacks and chosen-plaintext attacks. Additionally, it is with certain ability to resist the noise.At last, the problems of the chaos applying on image encryption are discussed. Then the field of the research in the future is indicated.