Copyright Protection Technology Based On Digital Watermarking

The development of multimedia technology and network technology has made media security a very important issue. In recent years, some new concepts of information security have been proposed, especially in the application of intellectual property right protection, copyright protection and Tamper-proofing. Information hiding and digital watermarking are new measures of digital media protection, which are processes of embedding hidden messages within digital media such as text, images, video and audio. The hidden messages could be copyright information, user distributor identification number, company logo, personal signature, control bits, or any information considered useful for a specific application. This dissertation mainly focus on some key problems, such as the development and application of water marking on copyright protection, the compose of water marking and the peculiarity of arithmetic, watermark attack and countermeasure, the authentication system by digital signature and the system by fragile watermark. Taking still image as an example, the watermark are embedded in the discrete wavelet domain of an image, so tamper detection is possible in localized spatial and frequency regions. Specially, this method can provide information on specific frequencies of the image that have been modified. This is different to previously proposed techniques. The result of experiment shows that this method is effective.