How can the app help?
The app developed by SAP and Deutsche Telekom on behalf of the German government is designed to help trace chains of infection as quickly and comprehensively as possible. Currently, health authorities have to do this in painstaking detail. This takes a lot of time, during which unknowingly infected contact persons can pass on the virus. There are also gaps because anonymous encounters cannot be traced.
The corona tracing app therefore offers the following advantages:
- The app works quickly. Contact persons who have installed the app are informed of contact with an infected person in the shortest possible time and can take precautionary measures.
- The app also records anonymous encounters, such as on the bus, in a supermarket queue or while sunbathing. Normally, these contacts would not find out that there was a direct risk of infection.
- This also applies to forgotten contacts – such as a chat with a neighbor in the stairwell.
New function: event registration
The Warn app offers a new function with the 2.0 update: It now includes an event registration option. This can be used to check in at retail outlets, events or private meetings using a QR code.
This distinguishes it from the privately developed Luca app, which many people already use, but which is often criticized for its data insecurity.
Digital vaccination certificate from the summer
Another feature is set to follow in summer 2021: the digital coronavirus vaccination certificate. With this certificate, users will be able to prove that they have been fully vaccinated. People who have recovered from coronavirus can also use the app to prove this. It is also designed to display negative coronavirus test results.
How does the app work?
The corona tracing app works via Bluetooth technology. Bluetooth, for example, connects cell phones wirelessly to loudspeakers or headphones. In contrast to this “conventional” connection, the Corona-Warn-App uses Bluetooth technology that consumes significantly less power (BLE = Bluetooth Low Energy). In this way, the cell phone determines how close a person comes to another person who also has the app installed. The duration of the encounter is also registered.
Closer than two meters, longer than 15 minutes
A distance of less than two meters over a period of 15 minutes is considered a critical distance. Infection is then considered a good possibility.
“Digital handshake”
When people whose smartphones are equipped with the tracing app meet, the devices exchange certain identification numbers – a “digital handshake”, so to speak.
Anonymous local storage
The contacts are only stored locally on the respective cell phone, anonymously. Each device randomly generates a new identification number (ID) every 20 minutes to provide additional privacy protection. The user’s location, movement profile or identity are not recorded.
Deletion of data after 14 days
After 14 days, when the incubation period for the disease ends, the contact is automatically deleted.
What happens if a user tests positive for Covid-19?
If a tracing app user reports a positive Covid-19 test, all temporary IDs that their cell phone has generated in the past 14 days are sent to a server. There they are available for comparison by all other users.
What can’t the app do?
The Corona-Warn-App is aimed at risk situations in which droplet infection can occur. For a long time, this was considered the main transmission route. However, it is now known that most people are infected via virus-containing, suspended micro-droplets (aerosols).
This transmission mainly takes place in closed, poorly ventilated rooms – and over distances of several meters. The Robert Koch Institute (RKI) confirmed to us that the app cannot recognize these risk situations.
In addition, the app does not distinguish whether people were wearing a face mask when they met. According to recent studies, wearing masks can significantly reduce the risk of infection for other people.
How reliable is the app?
The app is not infallible. A key factor here is the Bluetooth measurement, which was not developed for this type of use. The signal varies in strength from cell phone to cell phone. It also makes a difference whether you carry your cell phone in your pocket or open in your hand.
When asked, the RKI explained that there were various test scenarios for this, including standing in line, at a party or on public transport.
Misjudgements inevitable
The developers have not yet provided any information on how often such false reports could occur.
How secure is my data?
Unlike coronavirus apps in other countries, user movement profiles are not recorded, as would be possible via GPS, for example.
Decentralized approach
The German corona tracing app is also based on a decentralized approach. Anonymized contact data is stored on the respective smartphones. The contacts are not checked on a central server, but on the smartphones themselves. This is intended to prevent the contact data from being hacked and accessed by unauthorized persons.
Code visible to everyone
In order to rule out security vulnerabilities from the outset, the developers have published the app’s entire programming code so that it can be viewed and checked by anyone.
The Chaos Computer Club, a very critical advocate of data protection, now rates the security of the app as positive due to the decentralized data storage and the disclosure of the code.
Can the app be misused maliciously?
However, not all laboratories are equipped for this. Alternatively, the infected user can obtain a TAN from the public health department. They will first check whether the user is trustworthy.
Is use of the app voluntary?
Installation and use of the corona tracing app is voluntary. It is not installed automatically, but must be actively downloaded. Users who test positive are also not obliged to enter the test result in the app. App users who receive a warning are also not obliged to take action – for example, to have themselves tested or to isolate themselves.
Nevertheless, some parties are calling for legislation to stipulate, for example, that employers may not order the use of the app or that access to certain services and locations such as airports, restaurants or care homes may not be reserved exclusively for app users.
Who can use the app?
You currently need a smartphone with Bluetooth to use the app. This function must also be switched on at all times.
Apple provides the app for iPhones from operating system version iOS 13, Google for devices from operating system Android 6.
