CNS Core: Medium: Privacy-Preserving and Censorship-Resistant Domain Name System

域名系统(域名系统)是互联网的电话簿，它将人类友好的域名映射到IP地址。如果没有域名系统，互联网本身就无法正常工作。尽管几十年来一直在努力保护互联网上的用户隐私，但对于域名系统来说，隐私仍然是一个悬而未决的问题。通常，对DNS解析器的访问可以实现流量监听，即了解谁在寻找什么。此外，域名系统是一种完美的审查工具：阻止用户解析域名是审查互联网上免费和开放访问的最简单且经常被利用的方式之一。该项目旨在回答的关键问题是能否开发出真正的隐私保护和抗审查的域名系统。该项目的关键论点是，确保完全用户隐私的唯一方法是让域名服务器盲目地执行其工作，即通过在不知道域名是什么的情况下解析域名。后一种说法似乎有悖于直觉，但实际上存在几种允许这种操作的技术。这些技术属于私人信息检索(PIR)的分支，它是通过各种密码工具(如同态加密)实现的。长期以来，由于性能瓶颈，PIR协议一直被认为不切实际。初步研究和性能基准测试表明，在查询时间、流量开销和支持的数据库大小方面，PIR的性能正在向实际可用的领域迈进。该项目的主要目标是通过利用DNS系统的固有特性和共同设计新的PIR协议来使PIR适用于DNS，从而使完全抵抗DNS的隐私和审查成为现实。该项目通过实现一个可扩展、可增量部署、隐私保护和审查弹性的DNS系统，具有潜在的重大影响。私人投资机构计划以开放源码方式设计和传播该系统的实施。预计流行的浏览器将通过为支持单服务器PDNS的网站显示一个类似于HTTPS的图标来支持拟议的隐私保护系统。这项拟议的研究具有超越计算学科的社会影响，因为该项目的结果可能导致互联网上用户隐私方面的根本性增强。此外，它可以朝着挫败网络级别的审查迈出重要的一步，从而导致自由和开放的互联网和社会。与该项目相关的所有数据，包括测量数据、代码和结果，将在http://networks.cs.northwestern.edu/PDNS/.公开和公开提供该网站将在项目期间维护，所有数据在项目完成后至少5年内仍可从网站下载。该奖项反映了NSF的法定使命，并已通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

The Domain Name System (DNS) is the phonebook of the Internet which maps human-friendly domain names to IP addresses. Without DNS, the Internet itself would not function. Despite the decades-long efforts to protect user privacy on the Internet, privacy remains an open issue for DNS. In general, access to a DNS resolver enables traffic snooping, i.e., realizing who is looking for what. Moreover, DNS is a perfect vehicle for censorship: preventing users to resolve domain names is one of the simplest, and often utilized, way to censor free and open access on the Internet. The key question this project aims to answer is whether a truly privacy-preserving and censorship-resistant DNS can be developed.The key thesis of this project is that the only way to guarantee full user privacy would be for the DNS server to do its job in the blind, i.e., by resolving domain names without knowing what they are. The latter statement seems counter-intuitive, but in reality several techniques exist which allow such operations. These techniques fall in the branch of Private Information Retrieval (PIR), which is achieved by various cryptographic tools such as homomorphic encryption. PIR protocols have long been considered impractical due to performance bottlenecks. The preliminary research and performance benchmarks demonstrate that the PIR performance is moving towards the practically usable territory in terms of query timescales, traffic overhead, and supported database size. The main goal of this project is to make PIR applicable to DNS by leveraging inherent features of the DNS systems and co-designing novel PIR protocols, thus making the full DNS privacy and censorship resistance a reality.This project has the potential to make a significant impact by enabling a scalable, incrementally-deployable, privacy-preserving, and censorship-resilient DNS system. The PIs plan to design and disseminate, as open-source, implementations of the system. It is expected that popular browsers will support the proposed privacy-preserving system by showing an icon, similar to the one for HTTPS, for the websites that support the single-server PDNS. The proposed research has societal impacts beyond the computing discipline because results from this project could lead to fundamental enhancements in terms of user privacy on the Internet. Moreover, it can make an important step towards thwarting network-level censorship, thus leading to free and open Internet and society.All the data associated with this project, including measurement data, code, and results, will be made publicly and openly available at http://networks.cs.northwestern.edu/PDNS/. This website will be maintained for the duration of the project, and all the data will remain available for download from the website for at least 5 years after the project is completed.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.