Supported by a dedicated Protect Scotland website, the app is an extra tool complementing existing person-to-person contact tracing which remains the main component of NHS Scotland’s Test and Protect system. Individuals privacy will be protected as the app uses Bluetooth technology to anonymously alert users if they have been in close contact with someone who has tested positive for COVID-19, and advises them to self-isolate. Users of the app who test positive will still get a call from a contact tracer to confirm their details and who they have been in close contact with. The app does not store details on an individual or their location but uses encrypted, anonymised codes exchanged between smartphones to determine all close contacts. Close contacts are defined as people who have been within two metres of someone who has tested positive for 15 minutes.