The Corona Warning app is about to be released. After a long debate about data protection, the focus is now on how exactly the app works and whether it can actually help contain the pandemic.
Berlin (dpa) - The developers of the German Corona warning app are confident after extensive tests that the planned distance measurement via Bluetooth radio will also work in everyday life.
"We are now convinced that we have a good solution that you can start with - even if we know that it is not perfect," said SAP Manager Jürgen Müller of the German Press Agency.
The official German app is expected to be released in the next few days. It is based on the smartphone interfaces from Apple and Google and was developed by SAP and Deutsche Telekom. The app is designed to help track infections and interrupt the chain of infection at an early stage. The app records which smartphones have come close to one another - and then warns users if it turns out that they have been next to infected people. "The goal is for millions to participate," said Müller.
The Fraunhofer Institute IIS in Erlangen tested the German specific scenarios: sitting in a restaurant, standing in line, staying on public transport. It was measured how precisely the smartphones recognized the distance. "We will learn even more in real use," said Müller.
Google and Apple got a list of the 50 most used smartphone models in Germany from Deutsche Telekom, said the boss of the Telekom business customer subsidiary T-Systems, Adel Al-Saleh. This was necessary to adapt the distance estimation algorithms to the individual devices. This is particularly important for the Google Android operating system, where there are a variety of devices from different manufacturers with different components and software. The way the process is structured should have little impact on battery life. The Bluetooth LE (Low Energy) that is used consumes little power anyway. There would only be a greater load on the battery if the main processor were activated and other applications such as e-mail or social media apps also started.
For the warning function, the devices exchange randomly generated crypto keys via Bluetooth. These keys are not sent permanently, but at intervals of two and a half to five minutes as a salvo of 16 keys within four seconds. The distance is estimated based on the signal strength. A problem with Bluetooth technology is that the smartphones do not recognize when there is a glass pane between two users and they cannot infect each other at all. In the same way, Bluetooth signals do not go through water - this means that two phones may not be able to see each other when there are human bodies in between.
A central element of the Corona warning apps is the procedure by which infected people can share a positive test result in the app so that users who may have been infected are informed. The app partners had developed a form that all test laboratories in Germany should use so that the results are recorded in a standardized manner. During the test, everyone receives a QR code. Registering in the app also ensures that the test result is received on the phone. If the results are positive, users are expressly asked whether they want to share this for contact tracking. As an alternative to digital transmission, validation is available via a Telekom call center.
The developers received support from the IT service provider. TÜV information technology. The app will run stably and safely without spying on the users, said TÜV IT chief Dirk Kretzschmar on Saturday of the dpa. This was shown by an examination of the app on behalf of the Federal Office for Information Security (BSI).
When checking the app, they also checked whether unauthorized persons could tap data. "This is not the case. Users don't have to be afraid of surveillance." The developers at SAP and T-Systems had also ensured that no one had access to other data via the app.