How Apple and Google’s Bluetooth Tracing Key Aims to Safely Track COVID‑19 Exposure

On April 25 (US Eastern Time) Apple and Google announced a joint development of a "Tracing Key" product, similar to China’s health code, that uses Bluetooth technology to track the spread of COVID‑19 and inform smartphone users if they have been in contact with infected individuals.

The system, developed in cooperation with U.S. health authorities, requires widespread user participation and will operate on both iOS and Android devices without the need for a separate app.

Apple CEO Tim Cook disclosed the plan to EU Commissioner Thierry Breton after a video meeting, and Breton urged Apple to ensure the technology is anonymous, voluntary, transparent, temporary, secure, and interoperable to meet privacy standards.

France is also developing its own health‑code app but faces limitations due to Apple’s restrictions on third‑party Bluetooth data access. Google CEO Sundar Pichai has also been involved in discussions.

Both companies state that the system will be limited to use by health authorities, prohibiting government or third‑party access to personal data, and that all data will be deleted and the service withdrawn after the pandemic ends.

MIT researchers are similarly studying Bluetooth‑based contact‑tracing systems.

The technical workflow requires users to grant Bluetooth and GPS permissions; the phone then generates a local tracing key, a daily tracing key, and a rolling proximity identifier, all encrypted and stored locally, with new keys generated daily.

Confirmed COVID‑19 patients receive a special diagnosis key generated by a central server accessible only to public health agencies, while non‑infected users have a different set of keys. When a user’s device comes near a diagnosed patient’s device, the phones exchange keys and alert the user with details about the exposure, including duration, distance, and risk level.

The system also warns users about high‑risk areas and enables health officials to establish quarantine zones based on case clusters.

Ben Adida, Executive Director of Voting Works, expressed optimism on Twitter, noting that the software could benefit an open society as vaccines are developed.

In the coming months, Apple and Google will update their operating systems so that phones can share tracing information without installing additional applications.