Apple’s new Find My app will find your devices even if they are offline
At the company’s Worldwide Developer Conference keynote on on June 3, 2019, Apple executive Craig Federighi described a new location-tracking feature. The interaction is end-to-end encrypted and anonymous, even to Apple itself. The trick? You need to own at least two Apple devices.
Here is how the new system works:
- When you first set up Find My on your Apple devices, it generates a private key that is shared, communicated encrypted, among all your devices.
- Each device also generates a public key. This is the “beacon” that your devices will broadcast out via Bluetooth to nearby devices.
- That public key frequently changes, “rotates” to a new number.
- When someone steals your device, even if it is disconnected from the internet, it emits its rotating public key via Bluetooth.
- A nearby stranger’s Apple device, with no interaction from its owner, will pick up the signal, check its own location, encrypt that location data using the public key it picked up from your device, and upload to Apple’s servers.
- When you want to find your stolen device, you turn to your second Apple device, which contains both the same private key and has generated the same series of rotating public keys.
- Apple returns the encrypted location of your stolen device to your other device, which can use its private key to decrypt it and tell you the stolen device’s last known location.
Read more about it here.