Universal device pairing using an auxiliary device

Abstract

The operation of achieving authenticated key agreement between two human-operated devices over a short-range wireless communication channel (such as Bluetooth or WiFi) is referred to as "Pairing". The devices in such a scenario are ad hoc in nature, i.e., they can neither be assumed to have a prior context (such as pre-shared secrets) with each other nor do they share a common trusted on- or off-line authority. However, the devices can generally be connected using auxiliary physical channel(s) (such as audio, visual, etc.) that can be authenticated by the device user(s) and thus form a basis for pairing. One of the main challenges of secure device pairing is the lack of good quality output interfaces as well as corresponding receivers on devices. In [13], we presented a pairing scheme which is universally applicable to any pair of devices (such as a WiFi AP and a laptop, a Bluetooth keyboard and a desktop, etc.). The scheme is based upon the device user(s) comparing short and simple synchronized audiovisual patterns, such as "beeping" and "blinking". In this paper, we automate the (manual) scheme of [13] by making use of an auxiliary, commonly available device such as a personal camera phone. Based on a preliminary user study we conducted, we show that the automated scheme is generally faster and more user-friendly relative to the manual scheme. More importantly, the proposed scheme turns out to be quite accurate in the detection of any possible attacks.