Repairing the Bluetooth Pairing Protocol

Abstract

The Bluetooth pairing protocol is the one that takes place when two Bluetooth devices get together and want to authenticate to each other. I shall start by giving a high level summary of our work.

Firstly, “Look Ma, we can crack Bluetooth!”, we demonstrate a crack by a passive adversary. On its own this doesn’t look very interesting academically because, from the protocol itself, it is clear that this could be done. So next we ask if this problem can be fixed. The answer is affirmative, and we show how, but this looks like cheating because we fixed it in a way that the original designers of the protocol thought was not allowed. However we then argue that this was a sensible thing to do, and that maybe it is appropriate to relax the constraints that they set on themselves in the first place.