architecture-overview.md



Architecture Corona Warn App Mobile Client - Android
This document outlines the architecture of the CWA mobile client. It not necessarily reflects the current implementation status in this repository and will be enriched in the future, as development is ongoing.

Overview
The Corona Warn App Client ("CWA-Client") is a native mobile phone application developed for the mobile platforms iOS and Android. The CWA-Client is embedded into the overall Corona Warn App EcoSystem. (For an end to end overview please refer to the Solution Architecture Overview)
The key functionality of the CWA-Client is divided into the following pillars:


Exposure Tracing Management: The reliable activation as well as configuration management of the Mobile OS Exposure Notification Tracing functionality.


Exposure Risk Level Calculation: The calculation of the exposure risk level using the detected exposure events as well as the exposure risk configuration data.


Test Result Access: Access COVID-19 test results using a Test-GUID or a TeleTAN.


Diagnosis Key Submission: Allowing an COVID-19 positive tested user to share (submit) his TemporaryExposureKeys as DiagnosisKey.


Exposure Tracing Management
The Exposure Tracing Management component uses the native implementation of the Exposure Notification Framework provided by Google and Apple to activate, deactivate or check the status of the tracing functionality. If exposure tracing is activated by the user the activation-status of needed technical services (e.g. Bluetooth) is verified as well. To calculate the Exposure Risk Level of the user the active tracing time is considered. As a result initial tracing activation timestamp as well as the time were tracing was deactivated during the last 14 days is persisted.

Exposure Risk Level Calculation