Photo: Federal Government

Chancellor Dr. Angela Merkel said, “It has been worthwhile for us to ensure absolute transparency, comprehensive data protection and the highest level of IT security in development. Today we can say: This app deserves your trust. (Extract from the podcast transcript “Corona-Warn-App”, 20.06.2020)

The Corona-Warn-App is a project commissioned by the Federal Government. It helps to detect and effectively break chains of infection more quickly and more comprehensively. Based on a decentralised software architecture, the companies Deutsche Telekom and SAP have developed the application together with the Fraunhofer-Gesellschaft, Helmholtz-Zentrum CISPA and the Robert Koch Institute.

The chosen open source approach means that the full source code for the app, its documentation and infrastructure are freely available. The open source approach thus enables the public and the developer community to actively contribute to the success of the solution, e.g. by reporting errors or suggesting improvements directly on the GitHub platform. The app’s source code can also be checked independently.

The decentralised data storage ensures that the app meets the high German and European data protection requirements. In April 2020, a scientific debate was launched under the slogan “central vs. decentralised storage”. A loss of public confidence would have jeopardized all efforts and endeavours to detect chains of infection earlier with digital support and to interrupt them more quickly. That is why the Federal Government ultimately opted for a decentralised technical approach.

Data minimization: The users of the app remain anonymous at all times. You do not need to provide personal data such as email address and name when registering. The app only records encounters with other apps and analyses statistically whether there is a potential risk of infection for the user.

The application has been developed in an accessible manner and supports the common accessibility enhancements of the smartphone operating system. Additional versions of the app are gradually being released: in additional languages (e.g. since the beginning of July in Turkish) and for foreign app stores (e.g. since the end of June in Austria), so that the app also adds value for journeys within Europe.

Background information:
The Corona-Warn-App uses the Bluetooth Low Energy technique to measure the distance and contact time between people who installed the app. The mobile devices “note” encounters when the criteria laid down by the Robert Koch Institute, in particular distance and time, are met. Then the devices exchange random code keys. If people using the app are tested positive for the coronavirus, they can voluntarily inform other users. The random code keys of the infected person(s) are then made available to all those actively using the app. Once installed, it checks whether the user has met SARS-CoV-2-positive individuals. If that is the case, the app indicates a warning. The app works purely statistical: at no time can users, developers or the authorities verify who meets whom or who has been tested positively. 
As of July 3rd 2020, there are 14.6 million downloads of the app (Android and iOS).