Imperfections in your Bluetooth beacons allow for unstoppable tracking

Fingerprinting BLE with minor material variations in radio hardware.

It’s often said that there is a trade-off between privacy and convenience — while that’s often overstated, there are some ways in which it is inarguably true.

For example, it would be convenient to give all your devices radio chips that constantly broadcasted a unique number, and whenever one of our mobile devices encountered a radio beacon, it could log the event and the location.

Then, if we wanted to find something we’d lost, we’d have this great database of where-everything-is.

Likewise, if we wanted to do viral exposure notification, we could set our phones to broadcast a unique ID everywhere we went and log all the unique IDs it encountered.

When someone got a diagnosis, we could figure out who we might have been exposed to.

There’s just one problem: privacy. Both of these applications would produce a record of every location you visited and who you went there with. It’s a privacy nightmare.

Now, at this point, you may be noticing something curious: both of these services actually exist, and yet privacy advocates haven’t been shouting down the heavens…