KHOVID: Interoperable Privacy Preserving Digital Contact Tracing

TL;DR

KHOVID is a privacy-preserving digital contact tracing system that integrates manual and digital data using geolocation and Bluetooth, enhancing accuracy and privacy in pandemic contact tracing.

Contribution

KHOVID introduces a novel geolocation encoding mechanism and Bluetooth ID encoding to enable interoperable, privacy-preserving contact tracing combining manual and digital methods.

Findings

Prototype implementation demonstrates practical feasibility.

Simulation and field experiments validate accuracy and privacy features.

KHOVID outperforms earlier DCT proposals in privacy and interoperability.

Abstract

During a pandemic, contact tracing is an essential tool to drive down the infection rate within a population. To accelerate the laborious manual contact tracing process, digital contact tracing (DCT) tools can track contact events transparently and privately by using the sensing and signaling capabilities of the ubiquitous cell phone. However, an effective DCT must not only preserve user privacy but also augment the existing manual contact tracing process. Indeed, not every member of a population may own a cell phone or have a DCT app installed and enabled. We present KHOVID to fulfill the combined goal of manual contact-tracing interoperability and DCT user privacy. At KHOVID's core is a privacy-friendly mechanism to encode user trajectories using geolocation data. Manual contact tracing data can be integrated through the same geolocation format. The accuracy of the geolocation data from DCT is improved using Bluetooth proximity detection, and we propose a novel method to encode Bluetooth ephemeral IDs. This contribution describes the detailed design of KHOVID; presents a prototype implementation including an app and server software; and presents a validation based on simulation and field experiments. We also compare the strengths of KHOVID with other, earlier proposals of DCT.