Here’s How Apple’s COVID-19 Contact Tracing Technology Works

Apple and Google have partnered with each other to create a contact tracing API that will help prevent the spread of COVID-19 by alerting those who might have come in contact with a person positive with the virus. Apple calls this API Exposure Notification.

The new API was designed to work on both iOS and Android platforms, and is meant to help those who opt-in become aware if they might have contracted COVID-19 from someone who has it, so they can act accordingly.

Here's how Apple and Google's contact tracing technology works:

• Two persons (Person A and Person B) who are in close proximity to each other will have their smartphones sharing random Bluetooth identifiers with each other. These identifiers change from time to time, ensuring user privacy.
• If Person A is diagnosed positive with COVID-19, he will need to enter the test result in an app, which created by a public health authority using Apple's API. Users have full control over the data they want to share. If they input data into the app, their device will send all Bluetooth keys stored in it for the last 14 days to a server.
• Person B's smartphone will periodically (“at least once per day”) download Bluetooth identifiers to see if she has been in close proximity or in contact with someone who has registered positive. Her device will download a key that matches with Person A's Bluetooth identifiers. She will then receive a notification that will tell her what to do next.

Those who want a visual representation of how this works should see this image from Apple and Google:

Now, some more facts about the contact-tracing method:

• Apple and Google won't be the ones creating apps for the public. They will make the API available for developers so that public health authorities will be able to create their respective contact-tracing apps for their regions. Apple and Google will release it via the App Store and Play Store.
• Apple and Google will not be able to identify who tests positive for COVID-19. Data collection will require explicit user consent, and users have control over what kind of data they wish to share. Also, Bluetooth identifers will not reveal user identity and location. The feature works only using Bluetooth, not GPS.