TWC: TTP Option: Small: Collaborative: Enhancing Anonymity Network Resilience against Pervasive Internet Attacks

大规模的互联网审查使世界上许多地方的公民无法获取大量本来可以公开获得的信息。对这些审查事件的认识和公布有助于推动新的隐私增强技术的发展，以绕过审查。我们认为，随着规避技术的改进和检测其使用成本的增加，意图限制获取信息的对手将寻求替代技术来破坏。因此，了解这些替代中断技术以及它们如何影响网络匿名性、隐私性和性能，不仅对未来技术的成功设计至关重要，而且对现有网络和系统的安全性也至关重要。因此，本项目探索、设计和过渡到实践技术，这些技术将提高隐私增强技术的弹性，以应对这些现实的、但尚未充分研究的网络匿名性、隐私性和可用性威胁。我们认为对手超越了软件实现或协议的弱点，而是通过影响这些服务所依赖的共享资源来寻求破坏匿名服务的稳定。本项目研究互联网基础设施攻击如何应用于匿名网络。该研究设计了防御措施，提高了对此类威胁的弹性，并将此类防御措施转移到已部署的Tor网络。我们的研究活动(i)检查基于性能的资源攻击和设计隐私保护检测技术，不仅了解拒绝服务攻击如何消耗网络资源，更重要的是，如何自动检测和防止此类攻击；（ii）研究如何使用控制平面路由攻击来损害匿名性，并开发攻击缓解技术，以了解如何提高匿名网络抵御来自底层不受信任的互联网基础设施的威胁的弹性；（iii）分析人类移动性对匿名性的影响，以了解如何为现在无处不在的移动操作环境提供健壮和安全的匿名服务。这些活动有助于扩大未被充分研究的研究领域，不仅有助于改进未来技术的设计，而且还有助于提高现有网络和系统的安全性。

Large-scale Internet censorship prevents citizens of many parts of the world from accessing vast amounts of otherwise publicly available information. The recognition and publication of these censorship events have aided in motivating the development of new privacy-enhancing technologies to circumvent the censor. We argue that as circumvention technologies improve and the cost of detecting their use increases, adversaries that are intent on restricting access to information will seek out alternative techniques for disruption. As such, understanding these alternative disruption techniques and how they affect network anonymity, privacy, and performance is paramount not only to the successful design of future technologies, but also to the security of existing networks and systems. Accordingly, this project explores, designs, and transitions to practice techniques that will improve the resilience of privacy-enhancing technologies against these realistic but understudied threats to network anonymity, privacy, and availability. We consider adversaries that look beyond weaknesses in software implementations or protocols and instead seek to destabilize anonymity services by affecting the shared resources upon which these services depend. This project studies how Internet infrastructure attacks apply to anonymity networks. The research designs defenses that improve the resilience against such threats, and transitions such defenses to the deployed Tor network. Our research activities (i) examine performance-based resource attacks and design privacy-preserving detection techniques to understand not only how denial-of-service attacks can drain network resources, but more importantly, how to automatically detect and prevent such attacks; (ii) study how control-plane routing attacks can be used to harm anonymity, and develop attack mitigation techniques to understand how to improve the resilience of anonymity networks against threats from the underlying untrusted Internet infrastructure; and (iii) analyze the impact of human mobility on anonymity to understand how to provide robust and secure anonymity services to the now ubiquitous mobile operating environment. The activities help expand understudied research areas and not only help improve the design of future technologies, but also enhance the security of existing networks and systems.