On the security of password-based pairing protocol in Bluetooth

Bluetooth is a popular wireless communication technique, providing connection between portable or stationary devices in close range. A procedure called pairing needs to be performed when two devices intend to connect with each other in order to form a trusted pair and generate secret keys to protect the link. There are several modes of Bluetooth pairing, and password-based is the most convenient and prevalent way. In this paper, we discover a potential vulnerability in the password-based pairing protocol of the latest Bluetooth v4.0 proposed in 2010, which makes password guessing possible. To cope with the problem, a new scheme is proposed which can mitigate the network threats, and is compatible with the hardware of legacy Bluetooth devices. Note that our modification does not affect Bluetooth users´ custom. This makes it a suitable replacement for the new Bluetooth pairing protocol.