Research On Digital Fingerprinting And Application Of Copyright Protection In Digital Multimedia

The widespread use of Internet and digital technology facilitates the rapid development of media industry. Piracy also has become more and more a severe concern due to the easy modification, replication and redistribution of creative works in digital form. Copyright protection has becomes a crucial problem to be solved. Digital fingerprinting is a new effective technology to resolve multimedia copyright protection in recent years. The so-called digital fingerprint is characteristic sequences of an object that tend to distinguish it from other similar objects that can be processed by computer. Since fingerprint has the properties of uniqueness, robustness and invisibility, in the distribution of digital works, the merchant can embed unique buyer fingerprint into digital media copy, and also makes it possible to identify 'traitors' who redistribute their illegal copies and provide evidences for the court trial, thereby achieving the purpose of copyright protection.Digital fingerprinting is an integrated technology that combines information hiding and cryptography to constitute the system that protects digital rights of the content. The research of digital fingerprinting typically involves fingerprint embedding, fingerprint coding and fingerprint protocol technology. Digital fingerprinting has an advantage of copyright tracing that can monitor and control the whole process of the digital works from purchase, distribution, storage to utilization. Therefore, digital fingerprinting technology has a direct relation with electronic cash and electronic business and then can ensure the normal and regular circulation of the electronic commerce.This thesis is to research the security problem that emerges from digital multimedia security, intelligent copyright protection and electronic commerce. The thesis covers information hiding and cryptograph as applied to the design of digital fingerprinting on the fundamentals of signal processing, cryptography, coding theory and computational complexity. The focus is on efficient implementations of the fingerprinting scheme for copyright protection of digital multimedia in three major domains: fingerprint embedding, fingerprint coding andcorrelation protocol designing. In order to resolve the problems in the current research of digital fingerprinting, the endeavors of the thesis are listed as follows:1. In the aspect of fingerprint embedding, since digital fingerprinting often requires more channel capacity, this thesis presents a spread-spectrum CDMA watermarking scheme based on multiwavelet transform in terms of the parameter and performance analysis of spread-spectrum CDMA model. Moreover, a hybrid-watermarking model is also presented by integrating spread-spectrum with quantization technique according to the complementary relationship between both technologies in the aspect of robustness and capacity. The experiment results demonstrate that both schemes provide higher channel capacity under the precondition of robustness.2. In the aspect of fingerprint coding, to overcome the shortcoming of encoding length and decoding efficient, the thesis extends the adversary attack pattern according to the requirement of multimedia protection and then illuminates the collusion-resistant property of spread-spectrum fingerprint code. Moreover, the convolutional fingerprinting information code is presented by improving the viterbi algorithm of convolutional code to implement traitor searching. Finally, the thesis proposes a spread-spectrum convolutional fingerprinting scheme based on the above two schemes. The performance analysis shows the proposed scheme for perceptual media has shorter code length and more effective traitor searching.3. In the aspect of fingerprint protocol, to remedy the shortcoming of higher complexity and less practicability at present, the thesis presents an asymmetric fingerprinting scheme for transparent purchase based on collusion-resistant spread-spectrum coding, the security denotation decimal fixed-point and additive homomorphic cryptosystem. Furthermore, in terms of revoking blind signature, an anonymity fingerprinting scheme is proposed with transparent purchase to resolve the copyright tracing problem of digital works for purchase, distribution, tracing and trial.4. In the aspect of ownership proof protocol, to ensure the security of buyer's works and preventing the merchant from deceiving, a new algorithm of secure multiparty computation with error-tolerance capability is proposed on the basis of correct error theory and duality polynomial sharing. Furthermore, the thesis presents an ownership proofs scheme for digital works based on proactiveShamir secret sharing and secure multiparty computation protocol. The error-tolerance capability ensures that the proposed scheme can discover the dishonesty and keep it security and validity throughout the lifetime of the scheme. This thesis tightly integrates the above four aspects into one copyright protection scheme for digital multimedia. In order to validate the proposed algorithms and schemes, the performance and security of the schemes are analyzed and verified in both theory and experiment aspects. The results show that the proposed algorithms and schemes are effective and practicable.