开放环境下数字版权保护安全协议研究-智能与分布计算实验室

开放环境下数字版权保护安全协议研究

姓名	刘立刚
论文答辩日期	2006.06.15
论文提交日期	2006.11.13
论文级别	博士
中文题名	开放环境下数字版权保护安全协议研究
英文题名	Study on Security Protocol for Digital Copyright Protection under Open Environment
导师1	卢正鼎
导师2	陈晓苏
中文关键词	数字版权保护;数字水印;安全协议;协议验证;零知识;法律公证;权益保护;秘密共享
英文关键词	Digital copyright protection;Digital watermarking;Secure protocol;Protocol proof;Zero-knownledge;Legal notarization;Right protection;Secret sharing
中文文摘	数字媒体已经得到广泛的应用，但由于其具有易拷贝、易传输和易篡改等特性，使其版权保护受到了严重威胁，因此数字媒体的版权保护问题受到了广泛的关注。作为解决数字版权保护关键技术手段之一的数字水印技术已经开始应用到数字版权保护中。数字水印技术的应用研究大致分为两个方面：一是数字水印算法的研究；另一个是如何将数字水印算法应用到数字版权保护中，即应用协议的研究。版权保护协议有利于数字水印技术更好地服务于数字版权保护，因此开展数字版权保护协议的研究，具有十分重要的理论意义和实用价值。对现有数字版权保护过程中涉及的若干关键技术进行了分析，特别是对主流数字水印认证方法、数字指纹加密技术和公钥基础设施PKI（Public Key Infrastructure）等在开放环境下数字版权保护过程中的作用进行了比较和分析。在此基础上，对数字水印技术与传统的加密技术也进行了比较，并分析了传统加密技术在数字水印中的应用，指出了数字水印体制的哪一部分或哪些部分可以作为密钥。接着围绕基本作用和应用特征，分别对公开水印与私有水印、非对称水印与对称水印等概念进行了比较，并分析了它们的安全性。然后分析了数字水印在协议层可能会受到的主要攻击，如拷贝攻击、歧义攻击和倒置攻击等，给出了数字版权保护过程中针对这些攻击可采取的应对策略。通过在宿主信号中嵌入水印，同时采用了基于扩频的对称数字水印技术，提出了一个基于比特承诺的零知识数字版权认证协议。在该协议中，水印检测的密钥采用了比特承诺的形式提交给认证者，然后再通过交互协议，由认证者认证所嵌入的水印信息。给出了承诺方案的定义，并分析了协议的安全性。相对于已有的只能认证水印是否存在的方案，所给水印认证协议则能够提取出多个比特的水印信息，协议交互时所需要的数据量也相对较少。结合PKI技术的众多优越性，通过将数字水印技术与PKI的恰当结合，给出了一个数字媒体版权法律公证模型，建立了其总体框架，设计了数字媒体版权法律公证协议，包括数字证书的申请、时间戳机制、版权注册机制和版权认证机制，并对协议的有效性进行了分析。该协议从一定程度上解决了数字媒体版权发生纠纷时提供证据的公证性问题，从而能较好的解决数字媒体版权纠纷。在对已有公平交易协议分析的基础上，针对数字媒体分发过程中各参与方之间的公平性，同时兼顾从数字水印的内容、嵌入者和嵌入方式等方面各方在交易过程中可能会受到的侵权，给出了一个能在数字媒体交易过程中保证参与各方公平的权益保护协议。该协议将数字水印技术和数字签名技术结合在一起，通过在数字媒体中嵌入多方水印，使得在发现盗版时能够确定此盗版的相关责任人。针对多个实体拥有版权的情况，研究了多方秘密共享机制，并在基于中国剩余定理的秘密共享体系上提出了一个联合数字水印方案，对其中涉及的水印生成、水印嵌入、水印检测三个阶段要解决的问题以及相关技术措施进行了全面的讨论。在此基础上，设计了基于联合数字水印的多方秘密共享版权保护协议，并对协议的可用性和有效性进行了分析。基于所设计的数字版权认证协议、版权法律公证协议以及参与各方公平的权益保护协议，同时针对数字版权保护这一特定应用的需求，再辅之于对协议的安全性期望，设计了一个基于PKI和数字水印的数字版权保护安全协议。给出了数字版权保护安全协议的主要功能、处理流程以及性能，并用协议安全验证工具murphi对协议的安全性进行了验证。通过对开放环境下数字版权保护安全协议的研究，取得了一系列理论成果，对数字版权保护系统的设计与实现具有重要的指导意义。
英文文摘	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.