Epidemics like the recent COVID-19 require proactive contact tracing and epidemiological analysis to predict and subsequently contain infection transmissions. The proactive measures require large scale data collection, which simultaneously raise concerns regarding users' privacy. Digital contact tracing systems developed in response to COVID-19 either collected extensive data for effective analytics at the cost of users' privacy or collected minimal data for the sake of user privacy but were ineffective in predicting and mitigating the epidemic risks. We present Silmarillion--in preparation for future epidemics--a system that reconciles user's privacy with rich data collection for higher utility. In Silmarillion, user devices record Bluetooth encounters with beacons installed in strategic locations. The beacons further enrich the encounters with geo-location, location type, and environment conditions at the beacon installation site. This enriched information enables detailed scientific analysis of disease parameters as well as more accurate personalized exposure risk notification. At the same time, Silmarillion provides privacy to all participants and non-participants at the same level as that guaranteed in digital and manual contact tracing. We describe the design of Silmarillion and its communication protocols that ensure user privacy and data security. We also evaluate a prototype of Silmarillion built using low-end IoT boards, showing that the power consumption and user latencies are adequately low for a practical deployment. Finally, we briefly report on a small-scale deployment within a university building as a proof-of-concept.

翻译：类似于近期COVID-19的流行病需要主动接触追踪和流行病学分析，以预测并遏制感染传播。主动措施需要大规模数据收集，这同时引发了关于用户隐私的担忧。为应对COVID-19开发的数字接触追踪系统，要么以用户隐私为代价收集广泛数据以进行有效分析，要么为保护用户隐私仅收集极少数据，但在预测和缓解流行病风险方面效果不佳。我们提出Silmarillion——为未来流行病做好准备——一个协调用户隐私与丰富数据收集以提升效用的系统。在Silmarillion中，用户设备记录与安装在战略位置的蓝牙信标的相遇。这些信标通过地理位置、位置类型和信标安装地点的环境条件进一步丰富相遇数据。这种丰富的信息能够实现对疾病参数的详细科学分析，以及更精准的个性化暴露风险通知。同时，Silmarillion为所有参与者和非参与者提供的隐私保护水平，与数字和人工接触追踪所保障的水平相同。我们描述了Silmarillion的设计及其确保用户隐私和数据安全的通信协议，并评估了使用低端物联网板构建的Silmarillion原型，表明其功耗和用户延迟足够低，适合实际部署。最后，我们简要报告了在大学建筑内作为概念验证的小规模部署情况。