数字版权管理中的安全策略分析与选取

论文摘要

数字版权管理[Digital Rights Management, DRM)是近年来一个学科间具有挑战性的研究课题。在DRM支持的数字内容价值链中,多个参与方由于各自的利益并不存在完全的信任,致使安全技术成为构建多方信任的基础。现有的DRM安全技术研究主要集中在利用密码学算法与安全协议实现内容保护及安全分发,并且在一般或者特殊用途的用户终端设备上可信、可控地使用这些受版权保护的数字资产,以及基于数字水印技术的追踪和起诉版权侵犯行为等。毋庸置疑,这些典型的安全策略与使用限制对DRM系统是不可缺少的。然而另一方面,他们也带来了系统互操作性及用户可用性的显著降低,以及较高的安全成本。如果在选取和部署DRM安全策略时忽视了理性决策,简单地使用不断增强的安全策略将会给各参与方带来负面的效用影响。本文研究试图在DRM安全性与多方效用之间寻找折中,通过安全策略的合理选取与部署,实现价值链中各方之间一种最优的安全—效用平衡,从而有效地建立多方信任。本文主要贡献列举如下：1.提出了一个系统、完整的形式化分析框架,用于表述DRM安全组件/服务及其所组合策略的效用,进而完成策略的理性选取决策。这种新的框架包含了合作与非合作的博弈论分析,基于模糊层次分析法的效用影响因子权重评估,以及定量与定性相结合的面向增强安全策略的受控风险效用（Risk-Controlled Utility, RCU）分析方法。2.结合近年来出现的可信计算等安全增强技术,提出了一些DRM安全增强方案及应用。首先,基于对现有远程证明模型的剖析,提出了一种支持验证代理方的远程证明（Attestation Proxy Party-supported Remote Attestation, AP2RA）方案及其安全协议,该方案具有用户终端设备隐私保护这一重要特征。其次,面向数字内容分享场景,基于使用控制模型实现了数字权利委托/转移,并给出了AP2RA方案在DRM中的应用,这将满足在一个社会网络中用户之间分享数字内容的实际需求。最后,为了实施用户端的内容安全,以及内容提供商和用户之间的数字权利协商,给出了改进的两个安全策略。3.针对上面所提出的典型安全策略,面向一个基本的内容获取场景,给出了这些安全策略的效用函数以及主要因素的权重,然后重点提出了一个关于内容提供商、数字权利/服务提供商、以及用户等三方之间的非合作博弈模型,进而得出了纳什均衡及其存在条件。该均衡是一个对各方具有最优收益的安全策略组合。基于Swarm的仿真实验进一步验证了分析结论,并清楚地表明各方选取某一安全策略的趋势,它们随着内容交易事务的增加,以及高安全性所带来的管理和会话级成本与开销的降低,具有明显的改变并最后趋于稳定。此外,考虑到内容价值链中设备供应商的引入,一个合作博弈分析得出,提供方之间共同选取和部署安全策略,将会给各方带来最优的效用,相应的纳什均衡也将具有帕累托优势。4.对于一个更加复杂的DRM应用场景,数字内容分享普遍存在,着重提出了一个由提供商（Providers）和分享者（Sharer）两方参与的动态混合博弈（Dynamic and Mixed Game, DMG）,并试图得出一组有效的前提条件,在该条件下两方能够通过选取用户终端设备的远程证明等安全增强策略,从而获得最优的安全效用。为此,首先提出了一个简化的内容分享树结构,该结构属于社会网络的一种特殊形式。通过博弈论分析、DMG算法设计以及Swarm仿真实验,针对Sharer三种不同的分享模式,得出了Providers可选取的最优战略及其前提条件。此外,受安全风险管理的启发,评估了可信计算安全增强策略的RCU,并进一步分析了在数字内容侵权情形下,不同分享模式对Providers收益所造成的影响。最后,得出了有效的分享模式,并讨论了一个适用于数字内容分享场景的商业模型。

论文目录

• 摘要
• Abstract
• Table of Content
• List of Figures
• List of Tables
• List of Abbreviations
• 1 Introduction
• 1.1 Research Motivation and Scope
• 1.2 State-of-The-Art DRM
• 1.2.1 Cryptographic Security & Digital Watermarking
• 1.2.1.1 Cryptographic Techniques and Security Mechanisms
• 1.2.1.2 Digital Watermarking and Copyright Infringement Tracing
• 1.2.2 Digital Rights Expression and Usage Control
• 1.2.3 Trusted Computing and DRM
• 1.2.4 User Privacy Protection and Contents Security
• 1.2.4.1 Consumer Privacy Protection
• 1.2.4.2 Contents Security
• 1.2.5 DRM Trust Models
• 1.2.5.1 PKI-Based OMA DRM Trust Model
• 1.2.5.2 Web of Trust in DRM Ecosystem
• 1.3 Research Objective and Main Contributions
• 1.4 Thesis Outline
• 2 Formalized DRM Security-Utility and Game-Theoretical Analysis
• 2.1 DRM Security and Trust
• 2.1.1 A Generic Contents Value Chain Ecosystem
• 2.1.2 Requirements for Security and Trust in DRM
• 2.1.2.1 Fundamental Security Requirements
• 2.1.2.2 Essential Trust Relations
• 2.1.2.3 Conceptual Multi-Participant Trust Architecture
• 2.2 Formalized Game-Theoretical Adoptions of Security Policies
• 2.2.1 DRM Security Policies and Properties
• 2.2.2 Non-Cooperative Game on Security Polices
• 2.2.3 Cooperative Game on Security Polices
• 2.3 Fuzzy Analytic Hierarchy Process on Utility-Factor Weights
• 2.3.1 Analytic Hierarchy Process and Fuzzy Assessment
• 2.3.2 Hierarchy Process Structure and Consistency Matrix
• 2.3.3 FAHP-Based Weights Assessment
• 2.4 Risk Utility of Security Policy
• 2.4.1 Security Risk Management and Utility Category
• 2.4.2 Pros and Cons of Qualitative and Quantitative Assessments
• 2.4.3 An Analytic Approach to Risk-Controlled Uti-lity
• 2O'>2.4.3.1 Poisson Probability and VaR-based Calculation on AR²O
• 2.4.3.2 EF and UD Estimation by using Fuzzy Triangle Function
• 2.5 Conclusion
• 3 Enhanced Security Policies for DRM
• 3.1 Trusted Computing and Remote Attestation
• 3.1.1 Trusted Computing and Its Features
• 3.1.2 Remote Attestation
• 2RA Model and Secure Protocol'>3.2 AP²RA Model and Secure Protocol
• 2RA Model'>3.2.1 Privacy Protection and AP²RA Model
• 2RA Model and Components'>3.2.1.1 AP²RA Model and Components
• 2RA-Enabling Xen Platform'>3.2.1.2 AP²RA-Enabling Xen Platform
• 2RA'>3.2.1.3 Formalized AP²RA
• 3.2.2 Security Protocol
• 3.2.2.1 Attack Model
• 3.2.2.2 Secure Protocol
• 3.2.3 Analysis and Comparisons
• 3.3 Trusted Computing-enabled Digital Rights Sharing
• 3.3.1 Usage Control with Delegation Characteristics
• 3.3.1.1 UCON Framework and Delegation Objective
• 3.3.1.2 Delegation Properties
• 3.3.1.3 UCOND Formalized Definitions
• 3.3.2 Fine-Grained Digital Rights Transfer Policy
• 3.3.2.1 Fundamental Characteristics of Rights Transfer
• 3.3.2.2 Fine-grained rights delegation specification
• 2RA-Based Contents Dissemination System'>3.3.3 AP²RA-Based Contents Dissemination System
• 3.3.4 Trusted Distribution on Transferable Rights
• 3.3.4.1 DRM Architecture
• 3.3.4.2 RO Trusted Distribution Protocol
• 3.3.4.3 TRO Trusted Distribution and Enforcement Protocol
• 3.3.4.4 Performances Analysis and Comparisons
• 3.4 Digital Rights Negotiation and Contents Security
• 3.4.1 Transaction-Based Digital Rights Negotiation
• 3.4.2 Contents Verification and Trusted Execution
• 3.5 Conclusion
• 4 Basic Security-Utility and Game Analysis in Contents Acquisition Scenario
• 4.1 DRM Typical Security Policies
• 4.1.1 Typical Security Policy Set
• 4.1.2 Security Policies Relativity
• 4.2 Security Utility Analysis
• 4.2.1 Payoff Functions of Security Policies Combinations
• 4.2.2 Util-ity-Factors Weights Assessment and Calculation
• 4.3 Non-Cooperative Game on Typical Policies Set
• 4.3.1 A Non-Cooperative Game Model
• 4.3.2 Nash Equilibriums and Conditions
• 4.3.3 Swarm Simulations and Discussions
• 4.4 Cooperative Game for Typical Policies
• 4.4.1 Security Benefits Super-Additiontivity and Convexity
• 4.4.2 Establishment of Multi-Participant Cooperation
• 4.5 Conclusion
• 5 Security Policies Analysis and Risk Assessment in Contents Sharing Scenario
• 5.1 Rights Delegation and Transfer for Contents Sharing
• 5.2 Dynamic and Mixed Game for Contents Sharing
• 5.2.1 Rights Sharing Tree and DMG
• 5.2.2 An Algorithm for DMG
• 5.3 Swarm-Based Simulation Experiments
• 5.3.1 Basic Simulation Environment and Procedure
• 5.3.2 Simulations Experiments on Different Sharing Modes
• 5.4 Risk-Controlled Util-ity Analysis and Business Model
• 5.4.1 Risk Utility of TC-Enabling Security Policy
• 5.4.2 Sharing Modes and Maximum Benefits of Contents Purveyor
• 5.4.3 Simulation Experiments
• 5.4.4 Related Discussions and Business Model
• 5.5 Conclusion
• 6 Conclusions and Future Works
• 6.1 Conclusive Remarks
• 6.2 Future Works
• Acknowledgements
• 致谢
• References
• Appendix A
• Research Works and Published Papers for Ph.D.Degree