Automated Device Pairing for Asymmetric Pairing Scenarios

“Secure Device Pairing” is the process of bootstrapping secure communication between two human-operated devices over a short- or medium-range wireless channel (such as Bluetooth, WiFi). The devices in such a scenario can neither be assumed to have a prior context with each other nor do they share a common trusted authority. However, the devices can generally be connected using auxiliary physical channel(s) (such as audio, visual) that can be authenticated by the device user(s), and thus form the basis for pairing.

Recently proposed pairing protocols are based upon bidirectional physical channels. However, various pairing scenarios are asymmetric in nature, i.e., only a unidirectional physical channel exists between two devices (such as between a cell phone and an access point). In this paper, we concentrate on pairing devices using a unidirectional physical channel and analyze recently proposed protocol on this topic [14]. Moreover, as an improvement to [14], we present an efficient implementation of a unidirectional physical channel based on multiple blinking LEDs as transmitter and a video camera as a receiver.