There is global consensus that the best way to combat the spread of the novel coronavirus is to avoid contact with COVID-19 patients. Consequently, there are many ongoing efforts to develop contact- or proximity-tracing technologies. While the world awaits the arrival of the collaborative contact-tracing technology from Google and Apple, leading European institutions have been working together to develop a parallel app-based system that works with its own protocol. The project, initially launched by researchers from EPFL and ETH Zurich, has now been tested in the field with the help of the Swiss Army.

As the name implies, the international Decentralized Privacy-Preserving Proximity Tracing project (DP3T)1 focuses on data privacy and negates any chance of data being misused by hackers. Data is stored on each user’s phone in the form of signals that can only be used for contact tracing and not to collect or disseminate private information such as location, identity, or usage details. Developed within a relatively short time, the DP3T app was first tested on the EPFL campus and then shared with Swiss army personnel for a field test.

In the first stage of the field test held in late April, Swiss Army soldiers were asked to go through daily activities like shopping or sitting on a train, and their locations were recorded and analyzed using special cameras from EPFL’S Computer Vision Laboratory (CVLab), led by Pascal Fua. The data on the physical positions of the soldiers was then compared with the proximity measurements recorded by the DP3T system.

The second stage of the field test was conducted at a military facility by Mathias Payer, head of the HexHive lab in EPFL’s School of Computer and Communication Sciences. A beta version of the Bluetooth-based proximity-tracing app was installed on the phones of about 100 soldiers. The app continued to run as the soldiers went through their normal training schedule, which included physical training, theoretical study, and target shooting. A record was maintained each time a recruit was “less than two meters for more than five minutes” from another person. The DP3T app continued to work regardless of the phone’s location in the pocket, hands, or backpack. The data signals, including those received from nearby phones, were stored on each user’s phone. To test the efficacy of the app, one of the soldiers was designated as if he had tested COVID-19 positive, and his contacts were then traced through the app data without divulging personal details.

As lockdown rules slowly relax, there is a higher possibility of transmission of the virus. DP3T, which ensures “privacy by design,” could help break that chain of transmission. The scientists plan to complete the testing parameters and publish the results online for feedback and improvements. A beta version is expected later this month, and the app could be rolled out to users thereafter, pending approval from the Swiss government.


1  The DP3T team includes researchers from EPFL, ETH Zurich, and many other European institutions.

The EPFL team includes Alfredo Sanchez, Apostolos Pyrgelis, Carmela Troncoso, Dominique Quatravaux, Edouard Bugnion, Daniele Antonioli, James Larus, Jean-Pierre Hubaux, Ludovic Barman, Marcel Salathé, Mathias Payer, Pascal Fua, Sylvain Chatel, Theresa Stadler, and Wouter Lueks.

The ETH Zurich team includes David Basin, Dennis Jackson, Jan Beutel, Kenneth Paterson, and Srdjan Capkun.

Other European researchers include Bart Preneel, Nigel Smart, Dave Singelee, and Aysajan Abidin (KU Leuven); Seda Gürses (TU Delft); Michael Veale (University College London); Cas Cremers (CISPA Helmholtz Center for Information Security); Reuben Binns (University of Oxford); and Ciro Cattuto (University of Torino / ISI Foundation).

In Switzerland, the project is being coordinated by the National COVID-19 Science Task Force of the Swiss Federal Council, and is officially supported by the Swiss Federal Office of Public Health (FOPH).