Research On Authentication Algorithm Combining Digital Signature And Digital Watermarking

Digital watermarking and digital signature are two important branches of the hidden information technology, which embed protection information and authentication information with author's copyright into a variety of digital products such as images, audio, video and software in order to distinct illegal copy and protect intellectual property rights. As the top technology in the current multimedia information security field, digital watermarking and digital signature technology have been attached great importance in the international academic and business circles.This thesis firstly points out the significance of digital watermarking and digital signature technology in science research and industry production, which is based on the background of native and broad study, and analyzes the current status and developing trend of digital watermarking and digital signature technology, this thesis deeply studies semi-fragile watermarking and digital signature technology.This thesis studies self-adaptive watermarking algorithm based on the discrete cosine transformation (DCT). Combining DCT with just noticeable difference (JND), which are embeded into the original image, this algorithm is very invisible, robust and semi-fragile. Then self-embedded watermark algorithm based on DCT is studied, this algorithm can not only locate the position of tampering, but also be able to recover the revised content, which enhances anti-attack. Finally this thesis studies an authentication algorithm combined digital signature and digital watermarking technology, this algorithm embeds the watermark using the above self-embeded algorithm, and adopts double identity authentication mechanism, which certifies the user's identity and information content. It ensures the credibility of the conversation and prevents to fake and tamper of information and enhances the security of certification process. The experimental results and analysis show that using the authentication algorithm can enhance the security of certification process, which provides a new way on the research of authentication system.