Corona-Warn-App: Tracing the Start of the Official COVID-19 Exposure Notification App for Germany

On June 16, 2020, Germany launched an open-source smartphone contact tracing app (“Corona-Warn-App”) to help tracing SARSCoV- 2 (coronavirus) infection chains. It uses a decentralized, privacy preserving design based on the Exposure Notification APIs in which a centralized server is only used to distribute a list of keys of SARSCoV-2 infected users that is fetched by the app once per day. Its success, however, depends on its adoption. In this poster, we characterize the early adoption of the app using Netflow traces captured directly at its hosting infrastructure. We show that the app generated traffic from allover Germany—already on the first day. We further observe that local COVID-19 outbreaks do not result in noticeable traffic increases.