As an additional measure to fight the COVID-19 pandemic, the Swiss government has commissioned the development of a contact-tracing smartphone application called “SwissCovid”. Despite being a desirable goal, it is not always possible to avoid mistrust and uncertainty among the public. To shed more light on frequently discussed concerns, this document aims to answer a number of frequently asked questions in an easily understandable, yet technically precise manner. A thorough and complete security assessment of the source code, the architecture or the protocol is not the subject of this document.
To this end, the authors had a close look at the available resources, in particular at critical points where issues were expected. The work of Vaudenay and Vuagnoux served as additional input.
General limitations of app-based contact tracing (such as medical and societal) are not discussed.
Thomas Bossard, Lena Csomor, Gian-Luca Frei, Michael Hartmann, Raphael M. Reischuk