There are a number of suggestions for the technical implementation of this concept. These proposals range from dystopian systems of full surveillance to targeted, completely anonymous methods of alerting potentially infected persons without knowledge of the specific person.
In principle, the concept of a «Corona App» involves an enormous risk due to the contact and health data that may be collected. At the same time, there is a chance for «privacy-by-design» concepts and technologies that have been developed by the crypto and privacy community over the last decades. With the help of these technologies, it is possible to unfold the epidemilogical potential of contact tracing without creating a privacy disaster. For this reason alone, all concepts that violate or even endanger privacy must be strictly rejected.