Application And Research Of Digital Watermarking On Image Copyright Protection

Being a new solution technique to multimedia information protection, digital watermarking has become a hotspot in the research of information security both at home and abroad. This dissertation researched the application of digital watermarking on copyright protection with the object of image. The main research efforts are summarized as follows:1. Two pivotal points of digital watermarking applied to images copyright protection are analyzed. Firstly, the basic theory and model, typical watermarking algorithms and the capability demanded are studied in robust watermarking. Secondly, the buyer-seller watermarking protocol and zero-knowledge watermarking verification protocol are analyzed. Finally, according to the analysis of watermarking attacks, robust watermarking against geometric attacks and the zero-knowledge watermarking verification protocol are referred as key and difficulty problems2. The theory and influence of geometric attacks are researched, and the extant watermarking algorithms against geometric attacks are classified and analyzed. Then a novel robust watermarking algorithm against geometric attacks is proposed based on the second generation watermarking. In the algorithm, DWT and image moment invariants are combined. By means of wavelet moment invariants, RST (rotation, scaling and translation) invariants are constructed, which are used for watermarking embedding. By theory analysis and simulation experiment, the algorithm is proved robust, especially to rotation, scaling and translation attacks.3. A zero-knowledge watermarking verification protocol based on RSA is presented to resolve the verification security problem. In the protocol, RSA is used to encrypt the sensitive information needed in watermarking verification to realize the public verification of copyright watermarking. Moreover, the strategy of preventing protocol attacks is considered. Some common protocol attacks can be resisted by the devised copyright registration sub-protocol. In the course of alternant protocol verification, by limiting ways of implementing communication protocol with the outside, the special attack—cheating attack to zero-knowledge verification protocol can be resisted effectively.At last, the research topics in digital watermarking are summarized and prospected.