A Privacy-Preserving Solution for Proximity Tracing Avoiding Identifier Exchanging

TL;DR

This paper presents a privacy-preserving proximity tracing method that uses GPS for detection and Bluetooth for accuracy, avoiding identifier exchange and complex cryptography, thus enhancing privacy and security.

Contribution

It introduces a novel proximity tracing approach that avoids exchanging identifiers and does not rely on cryptography, addressing privacy concerns in contact tracing apps.

Findings

Ensures user location privacy while detecting proximity.

Avoids cryptographic complexity in contact tracing.

Maintains accuracy with GPS and Bluetooth integration.

Abstract

Digital contact tracing is one of the actions useful, in combination with other measures, to manage an epidemic diffusion of an infection disease in an after-lock-down phase. This is a very timely issue, due to the pandemic of COVID-19 we are unfortunately living. Apps for contact tracing aim to detect proximity of users and to evaluate the related risk in terms of possible contagious. Existing approaches leverage Bluetooth or GPS, or their combination, even though the prevailing approach is Bluetooth-based and relies on a decentralized model requiring the mutual exchange of ephemeral identifiers among users' smartphones. Unfortunately, a number of security and privacy concerns exist in this kind of solutions, mainly due to the exchange of identifiers, while GPS-based solutions (inherently centralized) may suffer from threats concerning massive surveillance. In this paper, we propose a solution leveraging GPS to detect proximity, and Bluetooth only to improve accuracy, without enabling exchange of identifiers. Unlike related existing solutions, no complex cryptographic mechanism is adopted, while ensuring that the server does not learn anything about locations of users.