Corona-Warn-App – What It Can Do and How It Works [5 Reading Tips]

Last week, the long-awaited and hotly debated Corona-Warn-App was launched in the app stores in Germany. Developers and innovators from all over Germany have worked on the app – on a voluntary basis so to speak. In this week’s reading tips, we will show you how the Corona-Warn-App works and what makes it so special.

Corona-Warn-App as an Open Source Project

The app is developed by the software provider SAP and Deutsche Telekom. The source code for the app was already made freely accessible on the Internet at Whitsun. More than 60,000 people worked on it, many helped programme it and contributed their own ideas. That is open source style.

Under the direction of SAP software developer Martin Fassunge, the app is designed to track possible infection chains without making the people affected personally identifiable.

The Latest Coronavirus News – How the App Works

The app turns the smartphone into a small »Bluetooth beacon« and ensures that identification numbers are regularly transmitted to the surrounding area. At the same time, the smartphone checks whether it can receive Bluetooth signals from other devices. If users of the app spend a certain amount of time next to each other in a spatially limited area, an ID exchange between the smartphones takes place.

If people test positive, they can enter this information into the app on their own. In order to avoid false reports, this is only possible with a verification code issued by the public health department.

Does the Coronavirus Now Threaten Our Privacy as Well?

Not really. The ID exchange between smartphones ensures that no conclusions can be drawn about the people affected. Furthermore, it is impossible to know whether you are currently next to an infected person. Therefore, it is not the identities of users that are exchanged, but anonymised IDs that change several times per hour.

The IDs of the persons that have been in contact with someone who has tested positive for COVID-19 are not stored centrally, but decentrally on the respective smartphones. Only the list of anonymised IDs of infected persons is kept on a central server. However, the matching process takes place exclusively on the individual smartphones. In this regard, the privacy of users is not at risk.

You can transparently view the app’s source code on the GitHub platform. Several analyses of the code have so far not revealed any loopholes or other anomalies.

Criticism of the Corona-Warn-App

Since the Bluetooth technology was not primarily developed for measuring distances, there will certainly be some false alarms as well. Moreover, it can happen that infected persons are behind a glass wall and trigger the alarm although there is not really any danger of being infected.

Since older citizens in particular tend to have less technical know-how and are less likely to use the app than younger users, it provides relatively little added value for this at-risk group. In addition, a study from Oxford University shows that the app’s potential can only be fully realised if at least 60 per cent of the population use it. This will also be difficult.

Only practice will show how permanently enabling Bluetooth will affect the battery life of the devices. The developers have agreed on using Bluetooth LE (Low Energy) so that the app will actually consume less power than streaming music on Bluetooth speakers. As already mentioned, practice will show how successful this approach is.