The Corona Warn App is an app that helps trace infection chains of SARS-CoV-2 (which can cause COVID-19) in Germany. The app is based on technologies with a decentralized approach and notifies users if they have been exposed to SARS-CoV-2. Transparency is key to both protect the app’s end-users and to encourage adoption.
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How the Corona Warn App Works Best
The RKI as the publisher of the app and the Federal Ministry of Health, in co-operation with Deutsche Telekom and SAP, are constantly reviewing possible further developments as well as incoming development proposals. This also includes whether further information can be integrated into the app, for example on the latest pandemic situation. For that purpose we will continue to intensively incorporate the information that we receive via the various channels into our development process.
How does the app work?
Collect nearby identifiers
- The Exposure Notification System (by Apple and Google) on a mobile device broadcasts a Rolling Proximity Identifier (something to be remembered by), while also regularly scanning for identifiers of other phones using Bluetooth Low Energy technology and storing the identifiers locally. The identifiers are only valid for 10-20 minutes and are derived cryptographically from temporary keys which change every 24h.
Communicate test result of user with symptoms (optional)
- If the lab in question supports the electronic process, tested users can use the QR code they received during the test to retrieve their results.
Distribute list of keys of SARS-CoV-2 confirmed users
- In case of a positive test result, users are asked to voluntarily upload their temporary keys of up to the last 14 days to the server. To prevent misuse, the Corona-Warn-App backend first verifies the positive test result. If confirmed, the server adds the user’s keys to the SARS-CoV-2 confirmed list, which is regularly broadcasted to all apps.
Check for exposure to SARS-CoV-2 confirmed users
- After a mobile device has downloaded the list of all available keys of users that have tested positive, the Exposure Notification System derives the corresponding identifiers and checks locally if any of these match the locally collected Rolling Proximity Identifiers. In case of exposure, the risk is assessed and the user receives corresponding instructions.
What is the purpose of the digital COVID test certificate?
You can request the certificate by registering a test in the Corona-Warn-App (CWA): To do this, tap on ‘Register Test’ on the start screen of your CWA and then on ‘Scan QR Code’. After scanning the QR code for test registration, the window for the COVID test certificate automatically opens. There you can ‘request the test certificate’ or reject it if you do not want to receive one.
How long is my Corona test certificate valid?
How long the certificate is valid depends on the regulations of the respective federal state or municipality.
In which countries can the Corona Warn App be used?
Below is a list of currently participating countries and details of the responsible health authorities:
- Czech Republic
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