[论文解读] Contact Tracing: An Overview of Technologies and Cyber Risks

Franck Legendre, Mathias Humbert+2 more|arXiv (Cornell University)|Jul 6, 2020

COVID-19 Digital Contact Tracing被引用 12

一句话总结

本文全面分析了在新冠疫情疫情期间开发的基于智能手机的接触追踪技术，评估了其网络与信息安全风险。文章对比了PEPP-PT和DP-3T等主要框架，突出展示了实用性和隐私保护之间的权衡，并对数据滥用和恶意虚假警报等威胁提供了客观评估。

ABSTRACT

The 2020 COVID-19 pandemic has led to a global lockdown with severe health and economical consequences. As a result, authorities around the globe have expressed their needs for better tools to monitor the spread of the virus and to support human labor. Researchers and technology companies such as Google and Apple have offered to develop such tools in the form of contact tracing applications. The goal of these applications is to continuously track people's proximity and to make the smartphone users aware if they have ever been in contact with positively diagnosed people, so that they could self-quarantine and possibly have an infection test. A fundamental challenge with these smartphone-based contact tracing technologies is to ensure the security and privacy of their users. Moving from manual to smartphone-based contact tracing creates new cyber risks that could suddenly affect the entire population. Major risks include for example the abuse of the people's private data by companies and/or authorities, or the spreading of wrong alerts by malicious users in order to force individuals to go into quarantine. In April 2020, the Pan-European Privacy-Preserving Proximity Tracing (PEPP-PT) was announced with the goal to develop and evaluate secure solutions for European countries. However, after a while, several team members left this consortium and created DP-3T which has led to an international debate among the experts. At this time, it is confusing for the non-expert to follow this debate; this report aims to shed light on the various proposed technologies by providing an objective assessment of the cybersecurity and privacy risks. We first review the state-of-the-art in digital contact tracing technologies and then explore the risk-utility trade-offs of the techniques proposed for COVID-19. We focus specifically on the technologies that are already adopted by certain countries.

研究动机与目标

• 评估疫情应对中数字接触追踪技术的最新进展。
• 识别并分析与基于智能手机的接触追踪相关的网络安全与隐私风险。
• 澄清PEPP-PT与DP-3T等隐私保护接触追踪竞争框架之间的持续技术与伦理争议。
• 评估各国采用的不同接触追踪设计在风险-效用权衡方面的表现。
• 为非专业人士在复杂接触追踪技术格局中提供客观、专家级的综述。

提出的方法

• 基于其架构与密码学设计原则，对主要接触追踪框架（包括PEPP-PT与DP-3T）进行调查与比较。
• 分析接触追踪系统的威胁模型，包括数据泄露、监控以及恶意虚假警报等风险。
• 评估去中心化与集中式数据存储模式在保护用户隐私方面的角色。
• 评估临时ID与安全密钥交换等密码学原原子在降低追踪风险方面的作用。
• 审查国家级接触追踪系统中的实际部署与实现选择。
• 提供一个比较框架，以评估隐私保障水平及系统对网络威胁的抗压能力。

实验结果

研究问题

• RQ1 基于智能手机的接触追踪系统中固有的主要网络安全与隐私风险是什么？
• RQ2 与PEPP-PT等集中式模型相比，DP-3T等去中心化模型在隐私与信任方面有何不同？
• RQ3 哪些威胁向量可能危及用户数据或引发虚假隔离警报？
• RQ4 技术设计选择如何影响公共卫生效用与个人隐私之间的平衡？
• RQ5 机构对政府或企业机构的信任对接触追踪系统采纳与安全性有何影响？

主要发现

• 从人工接触追踪转向数字化接触追踪引入了显著的新网络风险，包括大规模监控以及政府或企业对数据的滥用。
• 去中心化系统（如DP-3T）通过将暴露日志本地存储于用户设备上，降低了集中式数据泄露的风险。
• 恶意行为者可能通过生成虚假警报，迫使个人进入不必要的隔离，从而破坏公众信任。
• PEPP-PT计划在关键贡献者退出后出现分裂，促成了DP-3T的形成，由此在专家间引发了技术和哲学上的争论。
• 本文指出，非专业人士在区分竞争性框架方面存在明显困惑，凸显了开展客观技术评估的必要性。
• 分析结论认为，隐私保护设计对于确保公众信任及接触追踪技术的长期采纳至关重要。