Public Key Digital Watermarking Systems

摘要

With the widespread of Internet and multimedia communication, how to protect the copyright of digital contents attracts more and more attentions, and becomes a crucial issue to be resolved. As an important branch of information hiding, digital watermarking will be an important means for copyright protection. Various digital watermarking systems were proposed in the last years, but almost all of them are symmetric, which implies that the key used for watermark embedding must be available at the watermark detector. This leads to a security problem if the detectors are implemented in consumer devices that are spread all over the world. Once the key is out of secret, the watermarks embedded in the digital content will be easily removed. Therefore, it is very important and urgent to develop asymmetric watermarking schemes, also named public key digital watermarking schemes, where the private key is used for watermarking embedding and the public key is used only for watermarking detection. In such a public key watermarking system, the private is kept for secret, and the watermarks cannot easily be removed with public key. Several latest proposed public key watermarking schemes are reviewed in the paper, and their performances are analyzed and present.