Digital Watermark Robustness Study

With the rapid development of computer and network, the daily life and work of human beings are becoming digitalized and networked. A large number of private data are transformed in the Internet, and electrical commerce is more and more popular. All these challenge the traditional method of copyright protection and technology of data security. In this background, digital watermarking is developed gradually. Digital watermarking technique is an available protection technique, which embeds an invisible structure into multimedia products in order to authenticate the ownership or transmit other available information. Based on the research and work of pre-scholars, regarding the situation of nowadays digital watermarking, some innovative work is done in this dissertation and is listed as follows.(1) Designed a method which combines the watermarking scheme and secure-fingerprint. The technique not only has the robustness and imperceptions ability of watermarking, but also can anti collusion attack. So it can be one method to track the transaction.(2) Uses combinatorial theory and constructs nonlinear DBBD (Differential Balanced Block Design) code as fingerprint for digital media (image, video, etc). The code can anti-collusion and has the capability of error correct. Based on the special characteristic of the code, designed the embedding, extracting and tracking scheme for the copyright protection.(3) Designed one innovative watermarking technique for tamper detection, which is a new technique for authentication and anti- counterfeit.