TWC: Small: Efficient Traffic Analysis Resistance for Anonymity Networks

担心自己隐私的互联网用户，包括告密者和极权国家的持不同政见者，依赖可靠的方式匿名访问互联网服务。然而，最近大众媒体公布的事件表明，这些服务在实践中几乎不提供隐私和匿名性。例如，最近的传票要求Twitter提供可疑维基解密支持者的连接细节，这表明政府可以很容易地发现网络用户的网络身份。为了恢复和促进互联网上的言论自由，需要一种通信系统，以保护用户不受通过他们的互联网活动-甚至是来自国家行为者等强大对手--的身份识别。这项拟议的研究将通过设计、实施和部署匿名通信网络来实现这一点，该网络可以防止窃听者识别互联网通信的来源、接收者或内容。与与Twitter等网站的直接通信相比，Tor等网络匿名服务提供了更高程度的保护，但不能承受流量分析(英国情报机构GCHQ正在积极开发一种技术，以消除Tor用户的匿名)。虽然一些研究人员提出了低延迟、抗流量分析的匿名网络设计，但这些系统的性能令人沮丧。本项目将调查匿名网络设计，这些设计对流量分析具有弹性，并且在一些现实假设下显示出可接受的效益/成本比。该项目将利用三个关键思想：(I)将可信的基础设施(用于混合流量)与不可信的P2P节点(用于可扩展性)相结合；(Ii)引入区域的概念，使用户能够选择他们信任其代理运行的司法管辖区；(Iii)利用通过经验观察到的通信工作负载的特性来开发提供可接受的性能/成本折衷的优化设计。其目标是在文件共享、网络流量和实时通信(VoIP)的强大对手模型下提供匿名保证的网络，并在固定线路和移动环境中均可工作。

Internet users concerned about their privacy, including whistleblowers and dissident citizens of totalitarian states, depend on reliable means to access Internet services anonymously. However, recent events publicized in popular press demonstrate that these services offer little privacy and anonymity in practice. For example, recent subpoena requiring Twitter to provide connection details of suspected Wikileaks supporters showed that governments can readily discover the network identities of Web users. To restore and promote free speech on the Internet, there is a need for systems of communication that protect users from identification through their Internet activity---even from powerful adversaries such as state actors. The proposed research will enable this through design, implementation, and deployment of anonymous communication networks that prevent eavesdroppers from identifying the source, recipient, or content of Internet communication.Network anonymization services like Tor provide a higher degree of protection than direct communication with Web sites like Twitter, but are not designed to withstand traffic analysis (a technique that the British intelligence agency GCHQ is actively pursuing to deanonymize Tor users). While several researchers proposed designs for low-latency, traffic-analysis resistant anonymity networks, the performance of these systems was discouraging. This project will investigate anonymity network designs that are resilient to traffic analysis and that exhibit an acceptable benefit-cost ratio under some set of realistic assumptions. The project will leverage three key ideas: (i) combine trusted infrastructure (for mixing traffic) with untrusted P2P nodes (for scalability); (ii) incorporate the notion of zones to give users the ability to select the jurisdiction in which they trust their proxies to run; (iii) leverage empirically observed properties of communication workloads to develop optimized designs that provide acceptable performance/cost trade-offs. The goal is to produce networks that provide anonymity guarantees under a strong adversarial model for file sharing, Web traffic and real-time communication (VoIP), and that work for both fixed-line and mobile environments.