Research On Realization Of Digital Watermarking For Joint Ownership

With the development of computer storage and transmission, the copyright protection of digital products becomes popular. Digital watermark, the invisible information embedded into digital products, can protect copyright and integrity of digital products. In recent years, scientists have made great progress in the research of digital watermark. However, various proposed digital watermark methods are designed for a single copyright owner. None of them can solve the problem of joint ownership. It is important to make research into the technique of digital watermark of joint ownership.How digital watermark for joint ownership is produced, embedded and detected is discussed. In the process of building watermark, watermark for joint ownership is produced by the secret key of joint ownership, at the same time, the key is splitted and distributed according to secret sharing scheme, then the owners of joint ownership can use fragments of key to produce watermark for individual identity. When embedding, both the individual watermarks and the watermark for joint ownership are embedded. When detecting, if the amount of joint owner reach the threshold, watermark for joint ownership can be detected, or else only part ownership can be admitted. The application of watermark for joint ownership can improve the security and redundancy of watermark information.Taking use of MATLAB, the production, embedding and detection of digital watermark for joint ownership is realized in experiment. The Asmuth-Bloom secret sharing scheme and DCT method for watermark embedding is applied in the experiment. The result of the experiment showed nice recognition of copyright for joint ownership.