Research And Designation Of Electronic Seal System Based On The Double Digital Watermarking

Nowadays the multimedia technology and the Internet are developing rapidly. Digital watermarking technology is one of the newest methods of digital production copyright protection and antigorgery techniques, but the ability of the digital watermark arithmetic is not enough suitable for resisting many attacks. How to improve the security of the watermark arithmetic is becoming the key problem to be solved.In this thesis, the fundamental concept, general model, classification and characteristic of the digital watermarking are summarized. In addition, classic algrithms, the method to evaluate a watermarking system and watermarking attacks are analyzed together.Taking still images as example, a novel watermark algorithm for images based on double digital watermarking was proposed. The original binary watermark was firstly pre-pressed by Arnold scrambling and chaos encryption means. The Arnold scrambled watermark embedded into DCT mid-band frequency coefficient of original color image's green components, and the watermark by chaos encryption embedded into by LSB method, so that the double watermark embedded into the original image. And the watermark can also be detected with the original image from watermarked image when needed.The watermark algorithm metioned above will application in an electronic seal system. In order to test the imperceptibility, robustness and brittleness of the algorithm, a lot of experiments are done. The experiment results demonstrate that the algorithm is imperceptible, very robust to attacks such as JPEG compression, cropping, additive noise and enhancement, and frangible to the tampered image. The algorithm achieves the protection of the electronic seal's property authentication and data integrality. Because of the simpleness and convenience, they may be expected to have a better application prospect.Using the method of object oriented analysis and designing, this paper designs an electronic seal system based on the double digital watermarking. This system solves the problem of electronic seal system embed and recover. This system is tight coupling to the windows operating system, is easy to be used.