• Michali Henig

Digital Contact Tracing during COVID19: What is the Corona-Warn-App and what is it good for?

Updated: Aug 26, 2020

On Tuesday, 16.06.2020, Germany had launched the Corona-Warn-App: an app which is designed to help the battle against Coronavirus using digital contact tracing.

The idea behind it is using technology in order to track chains of infection in an early stage, which can assist in cutting them, and therefore - allow us to go back to normal. In simpl words: if a user has caught COVID-19, the app can learn about it and notify the people who had been in contact with that infected person. That way, people can know that they are at risk of having caught COVID19 themselves and act accordingly, for example, get tested, monitor their health, avoid social contact or - depending on the degree of contact to the person with COVID19, put themselves into quarantine.

In the Macro-level, it is supposed to protect us as a collective - in a way that will allow taking care of breakouts locally, possibly without a lockdown and with minimum damage both to public health and to our economy.

As you probably have noticed, privacy is a big deal in Germany: with the collective experience of governments that did not put citizen and human rights as top priority, Germans are especially sensitive to the privacy of citizens and residents. As a result, the German Corona-Warning / Contact tracing app was designed with a special emphasis on user privacy.

In this blogpost I will address the main aspects of this topic, so that you can make an informed decision about whether or not you would like to install and use the app.

Where does this app come from? Who developed it?

The Corona-Warn-App is the app of Robert-Koch-Institut (RKI). It was developed by SAP and Deutsche Telekom, with a budjet of 20 Million Euros. According to official estimations, the app will cost more than 69 Million Euros until the end of 2021.

It is also important to say that this is a German app, which was developed for German users (and can therefore only be downloaded if you have a German AppStore/ GooglePlay account).

How does it work?

Once the app is installed on your phone, it will send and receive identification signals via Bluetooth. Those signals are anonymized in order to protect everybody´s privacy - so that the app cannot tell anything about the identity or personal information of the people you came across. It just knows that you were in the proximity of a certain signal - which came out of a certain phone.

In case of an infection, those signals become meaningful: In case someone has tested positive to Covid-19, they will be asked to report it to the app. In order to avoid abuse, the infected person will have to confirm their corona test results using either a QR code or a TAN that they received from the lab who ran the test. The app will then notify all holders whose phones sent out signals that were caught by the phone of the infected person. Those people will know they were in contact with someone who has COVID-19 and could therefore act befored they develop symptoms - by taking a corona-test and by putting themselves into quarantine.

Wait, I see many people every day - will I still have to go into quarantine even if I keep my distance?

The app can calculate the amount of contact an infected person have had to other people by the strength of the bluetooth signal. In simple words: if your friend with whom you were out having dinner caught COVID-19, the signal will most likely be strong, whereas if it was just a random person in the supermarket who was not physically close to you (since you of course keep the social distancing rules very very well, go you!) - the signal will most likely be weak.

However, Bluetooth technology was not developed in order to measure distance, which might lead to false positives (for example, as this technology cannot recognize glass walls). Therefore, the developers themselves admit that it can only contribute up to a certain limit, and that we should all keep the social distancing and mask-wearing rules.

Does the app have any other uses?

In the future, the app should also help users to get their corona-test results faster.

And what about my privacy?

As stated above, privacy - aka Datenschutz - is a big deal in Germany. Therefore, it was super important to keep everybody´s privacy as much as possible. The following measures were taken:

  1. The app does not keep personal information of users, but instead uses anonymized IDs. Those IDs change several times per hour.

  2. The IDs are kept on the smartphones of the app users - therefore guaranteeing decentralization in order to protect the users´ privacy.

  3. The use of the app is completely voluntary. We will not be forced to use it, we can download it if we want to.

  4. When downloading, users will have to sign the privacy policy and therefore agree to it. Of course, the policy will be tranparent - so that users could make an informed decision.

  5. Users may also choose to uninstall the app and stop using it if they choose to. As already stated, this is completely voluntary.

  6. The code of the app is open, and can be seen/ reviewed on GitHub - therefore guaranteeing that there are no hidden motives or scripts, and that the app is doing exactly what it is supposed to do.

And will it really help?

According to studies and the German press, the app will become effective if 60% of the population will use it. In this case, since it can break the infection chains, it can help us go back to normality as long as the pandemic is still threatening us.

Where can I find this app?

Easy. You can get the app on GooglePlay or on AppStore

In order to use it, you need to have a phone which supports IOS 13.5 (iPhone 6s. iPhone SE or newer). If you have an Android, you need at least a 6-version, and Google Play services have to run on your phone.

You can also find some official information and an explanation video in English here.


I am super curious to hear your thoughts about digital contact tracing, about the app and about other means in the fight against Coronavirus :)

18 views0 comments