Study On Security Protocol For Digital Copyright Protection Under Open Environment

The digital media already obtained the widespread application. With the characteristics of easy copying, transmission and modify, digital media copyright is threatened seriously; therefore, its protection of the copyright has received much concern. The digital watermarking technology as a solving digital copyright protection essential technical method has already started to apply to the digital copyright protection. The research on digital watermarking technology can be divided into two aspects approximately, one is the digital watermark algorithm study, and another is about how to apply the digital watermark algorithm to the digital copyright protection, namely application protocol study. The copyright protection protocol can help the digital watermarking technology serve well the digital copyright protection, therefore the development of digital copyright protection protocol research, has the extremely important practical significance and the theory value.Certain essential technologies involves the analysis to the existing digital copyright protection process, specially to the major watermarking proof methods, the digital fingerprint encryption technology, public key infrastructure (PKI). And these technologies function in the digital copyright protection process and the digital copyright protection security protocol model have been compared and analysed under the open environment. In this foundation, it has carried on the comparison to the digital watermarking technology and the traditional encryption technology, and has analyzed the traditional encryption technology in the digital watermark application, and has pointed out which part or which parts of digital watermarking system can act as the key. Centered about the basic function and the application characteristic of several pairs of the concepts, including the public watermarking and the private watermarking, the public key watermarking with the non-public key watermarking, the asymmetrical watermarking and symmetrical watermarking etc. we have compared them, and have analyzed their security and the main attacks of the digital watermarking possibly received in the protocol layer, like the copy attack, the ambiguity attack and the inversion attack and so on. We have produced and adopted the strategy of the digital copyright protection process in view of these attacks.Through embedding the watermark in the cover signal, at the same time adopting the spread frequency symmetrical watermarking technology, we have proposed a zero knowledge watermark proof protocol based on bit commitment. In this prptocol, the watermarking detection key uses the form of bit commitment to submit to the verifer, then through the interactive protocol, the verifer tests and proves the watermarking information. And we produce the commitment definition and analyse the protocol security. With contrast to some other watermarking schemes which only can confirm whether the watermarking exists, this given watermarking protocol can extract the watermarking information of several bits and it needs fewer data in interaction.Combined with the many advantages of the PKI technology, and through the appropriate combination of the digital watermarking technology and the PKI , we have given digital copyright legal notarization model and discussed its overall framework, thus, we have designed the digital copyright legal notarization protocol, including the digital certificate application, the time stamp mechanism, the copyright registration mechanism and the copyright authentication mechanism, and has analysed the protocol validity. The protocol has solved the authority problem when the dispute occurs to the digital media copyright from the certain degree, thus it can solve digital media copyright dispute better.Based on the analysis of the fair-trade protocol, in view of the fairness of each participator in the process of the digital media distribution, at the same time, much attention to these aspects including the digital watermarking content, embedders and embedding mode in which the right infringement possibly received in the transaction process, we have produced a protocol to protect the rights and interests of each participator in the digital media transaction process. This protocol is combined with the digital watermarking technology and the digital signature technology together. By embedding the watermarking in the digital media, it enables to confirm this pirate related owner, when it discovers the pirates.In the view of that copyright can be shared by multi-partners, the paper make a study on multi-partners secret sharing machine; and gives a joint watermarking algorithm based on Chinese Remainder Theorem. And the paper discusses fully about joint digital watermarking generation, embedding and detection. Further more, a sharing copyright protocol is presented that is based on joint watermarking. And the protocol's practicability, validity and security are also analysed.On the base of digital watermarking copyright proof protocol, digital copyright legal notarization protocol and participators fair right protection protocol, with special application requirement of digital copyright protection and its security expect, the paper designs a digital copyright protection security protocol based on PKI and digital watermarking. And the main functions, processing flow and performance of protocol are given. Protocol security is analysed by murphi, a protocol security analysis tool.Through the study on digital copyright protection security protocol under open environment, we achieve a series of theory results, which have significance for digital copyright protection system design and implement.