Research On Digital Watermarking Protocol

With the rapid development of computer network technology, traditional media services have been gradually replaced by digital products. Since digital products can be modified and copied with ease, a lot of copyright disputes get rising. Watermarking protocol, as an important research area of copyright protection, has been proposed to address the problems. It makes possible for people to protect the copyright of digital products and trace the traitors by using the related techniques. In recent years, a set of watermarking protocols with new mechanisms and algorithms have been proposed by scholars all over the world. However, there still exist various attacking breaches and drawbacks in those protocols. In this thesis, three watermarking protocols, which can be respectively applied to first hand transaction, second hand transaction, and multi-party transaction, have been proposed to solve the problems. The main research work is as follows.(1) Attacking analysis of previously proposed protocols is carried out in the thesis. Furthermore, the basic design requirements of watermarking protocol are well defined. And the detailed definition of the roles the third party plays in watermarking protocol is also given. These works provide a sound foundation for the further designing task of watermarking protocol.(2) A new interactive buyer-seller watermarking protocol is proposed through using new solutions of watermark embedding and encrypting. The protocol can effectively prevent against the collusion attacking by buyer and the third party, the collusion attacking by seller and the third party, and the intermediate personate attacking.(3) A new buyer-reseller watermarking protocol is proposed in the thesis. The protocol removes out the flaws of the protocol proposed by Cheung et al. In the protocol proposed in this thesis, it only needs the seller to provide the transfer certificate and decryption service to support the implementation of second hand transaction. And the security of the protocol can also be guaranteed.(4) A multi-party watermarking protocol is proposed in the thesis. The protocol successfully overcomes the difficulty in the combination between multi-cast mechanism and uniqueness of watermark. In the protocol, the seller can distribute the transaction information and digital products to n different buyers in multi-cast way. This multi-party watermarking protocol can also effectively prevent against the collusion attacking by buyer and the third party, the collusion attacking by seller and the third party, and the intermediate person attacking.