As a privacy designer I wanted to point out that the bluetooth-based contact tracing apps are not anonymous, even though they were often called that in public discourse. I also wanted to show how a bluetooth-free solution could work. This resulted in two websites:

CoronaDetective.eu reveals that the contact tracing apps that most European countries use were not guaranteed to remain anonymous.

CoronaMilder.nl demonstrates a bluetooth-free voluntary check-in system using QR codes of randomly generated numbers that represent locations.

The bluetooth apps work by having people emit codes, and having other people scan those codes. It’s a system where we trace people. With the QR codes solution we are instead tracing meetings. When John shares codes using CoronaMilder, he’s not sharing codes that uniquely represent him.

Learn more and see demonstration videos:

Schep, T. Corona Detective & Corona Milder. https://www.tijmenschep.com/corona-detective-corona-milder/