Research On Digital Image Encryption Technology

Nowadays, the information security of digital image has already become the international hot subject. Based on the advanced achievement in this field, this thesis discusses mainly the encryption technology in the security of digital image by using mathematics, cryptography, information theory etc. Firstly it explains the background, development, current situation and application of the digital image encryption technologies, which are summarized and classified. Secondly the thesis proposes a novel method of image encryption that is based on modern cryptogram system, and a formula that can evaluate the encryption result. Finally it uses the anti-counterfeit algorithm for commercial bills to practice the effect and influence of the digital image encryption in the digital watermarking.The details of the thesis are as follows:1. The summarization of the digital image encryption methods: According to the relevant papers, there are many kinds of the digital image encryption methods. By classifying these encryption methods and their characteristics, the thesis tries to offer relevant information for searching more suitable encryption methods.2. The digital image encryption algorithm based on modern cryptogram system: Modern cryptogram systems have offered a good cryptic foundation to the one dimension digital signal, and the digital image is finally turned into one-dimensional binary data when transmitted. In principle, the methods of modern cryptogram system are suitable for the digital image encryption. On the basis of studying modern cryptogram system, this thesis tries to apply it to encrypt the digital image. A digital image encryption algorithm based on DES is proposed in the thesis. The experiment shows the feasibility of the algorithm. What is more, it is robust to anti-attack tests such as partly-destroyed attack. Favorable avalanche effect increases the advantage of the algorithm even more.