Anonymous Collocation Discovery: Harnessing Privacy to Tame the Coronavirus

TL;DR

This paper introduces a privacy-preserving, Bluetooth-based scheme for detecting close contact with infected individuals during the COVID-19 pandemic, aiming to improve adoption and effectiveness without compromising personal privacy.

Contribution

It presents a simple, privacy-preserving contact detection method that does not require location data, enabling broad deployment with minimal infrastructure and low false positives.

Findings

Achieves fine-grained alerts while preserving anonymity

Requires minimal infrastructure and no personal data collection

Potential to enhance contact tracing adoption and effectiveness

Abstract

Successful containment of the Coronavirus pandemic rests on the ability to quickly and reliably identify those who have been in close proximity to a contagious individual. Existing tools for doing so rely on the collection of exact location information of individuals over lengthy time periods, and combining this information with other personal information. This unprecedented encroachment on individual privacy at national scales has created an outcry and risks rejection of these tools. We propose an alternative: an extremely simple scheme for providing fine-grained and timely alerts to users who have been in the close vicinity of an infected individual. Crucially, this is done while preserving the anonymity of all individuals, and without collecting or storing any personal information or location history. Our approach is based on using short-range communication mechanisms, like Bluetooth, that are available in all modern cell phones. It can be deployed with very little infrastructure, and incurs a relatively low false-positive rate compared to other collocation methods. We also describe a number of extensions and tradeoffs. We believe that the privacy guarantees provided by the scheme will encourage quick and broad voluntary adoption. When combined with sufficient testing capacity and existing best practices from healthcare professionals, we hope that this may significantly reduce the infection rate.