Security News > 2022 > June > Tracking People via Bluetooth on Their Phones

We've always known that phones-and the people carrying them-can be uniquely identified from their Bluetooth signatures, and that we need security techniques to prevent that.

Computer scientists at the University of California San Diego proved in a study published May 24 that minute imperfections in phones caused during manufacturing create a unique Bluetooth beacon, one that establishes a digital signature or fingerprint distinct from any other device.

Though phones' Bluetooth uses cryptographic technology that limits trackability, using a radio receiver, these distortions in the Bluetooth signal can be discerned to track individual devices.

Certain environmental factors can disrupt a Bluetooth signal, including changes in environment temperature, and some devices send signals with more power and range than others.

One might say "Well, I'll just keep Bluetooth turned off when not in use," but the researchers said they found that some devices, especially iPhones, don't actually turn off Bluetooth unless a user goes directly into settings to turn off the signal.

Most people might not even realize their Bluetooth is being constantly emitted by many smart devices.

News URL

https://www.schneier.com/blog/archives/2022/06/tracking-people-via-bluetooth-on-their-phones.html