Abstract : For the protection of people and society against harm and health threats — especially in case of the COVID-19 pandemic — a variety of different disciplines needs to be involved. The data collection of basic and health-related data of individuals in today’s highly mobile society does help to plan, protect, and identify next steps health authorities and governments can, shall, or need to plan for or even implement. Thus, every individual, human, and inhabitant of the world is the key player — very different from many past crises’. And since all individuals are involved his/her (a) health and (b) privacy shall be considered in a very carefully crafted balance, not overruling one aspect with another one. Privacy remains key. The solution of the current pandemic’s data collection can be based on a fully privacy-preserving application, which can be used by individuals on their mobile devices, such as smartphones, while maintaining at the same time their privacy. Additionally, respective data collected in such a fully distributed setting does help to confine the pandemic and can be achieved in a democratic and very open, but still and especially privacy-protecting manner. Therefore, the WeTrace approach and application designed utilizes the Bluetooth low energy (BLE) communication channel, many modern mobile devices offer, where public-key cryptography is being applied to allow for deciphering of messages for that destination it had been intended for. Since literally every other potential participant only listens to random data, even a brute force attack will not succeed. WeTrace and its Open Source implementation ensure that any receiver of a message knows that this is for him/her, without being able to identify the original sender
Index terms : Bluetooth low energy (BLE), contact tracing, COVID-19, privacy-preserving, mobile.