Private. Simple. Secure.

Compatible with 91.90% (UK) and 86.24% (GLOBAL) smartphones (June 2020).

• Anonymous reporting of infection status to help others.
• On-device matching of infection reports to help you.
• Does not collect any personal or location data.

• No registration, no setup, just install and go.
• Two taps to share your infection status.
• App will notify you to review new information.

• All sensitive on-device data is encrypted (Keychain).
• All network traffic is encrypted (https).
• Bluetooth beacon codes are randomised regularly.

Source code for iOS, Android and Java server are all available for inspection and reuse under MIT License.

This app does not use the Apple - Google Contact Tracing API that is compatible with 65.83% (UK) and 76.98% (GLOBAL) smartphones (June 2020).

• Bluetooth beacon
  • Works across iOS (10+) and Android (24+) without software update to latest version.
  • Works well under iOS and Android background mode.
  • Low energy usage and minimal bluetooth data exchange.
• Security
  • HTTPS for all network traffic.
  • AES encrypted message for submitting status updates.
  • Sensitive data encrypted on-device.
• Privacy
  • No user or device data is ever collected.
  • One-time download of shared secret on registration via HTTPS.
  • Published beacon code seeds cannot be traced back to device.

1. Install the latest Xcode developer tools from Apple.
2. Clone the repository.
3. Build and run project.

1. Install app on two iPhones and place them next to each other.
2. Ensure the iPhones have an internet connection, then start app on both phones.
3. The number of contacts tracked should increase and change regularly, confirming the phones are detecting each other.
4. Change "How are you today?" to "Symptoms" on one phone, and agree to share the information anonymously.
5. Update will be ready for download after 1 minute on the development server, this will normally be 1 day in production.
6. Tap "What you need to do" 4 times on the other phone after 1 minute to request immediate update.
7. "Recent contacts" should have changed from "No report..." to "Report of...has been shared" and "What you need to do" should change from "Stay at home" to "Self-isolation".

• Tap "Recent Contacts" 7 times to bring up developer function menu.
  • Cancel : Close developer function menu.
  • Simulate Crash : Cause app to crash and enter terminated state after 8 seconds, for testing state preservation and restoration. Detach app from Xcode and use Console to view log of Process:C19X to monitor app activities following termination.
  • Clear Contacts : Deletes all database data, to reset contact count to 0. Registration data is preserved.
  • Export Data : Write all contact and battery data in database to CSV files for access via iTunes file sync (Finder > Locations > Your Device > Files > C19X > "contact.csv, battery.csv"). Please note, beacon codes are not exported.
  • Clear All Data : Deletes all database, user defaults and key chain data. Registration data is deleted. This is equivalent to re-installing the app, except state preservation and restoration data is retained by iOS.
• Tap "What you need to do" 4 times to request immediate update of infection data from server, rather than waiting for automatic daily update.