Secure Device Pairing Based on a Visual Channel: Design and Usability Study

“Pairing” is the establishment of authenticated key agreement between two devices over a wireless channel. Such devices are ad hoc in nature as they lack any common preshared secrets or trusted authority. Fortunately, these devices can be connected via auxiliary physical (audio, visual, tactile) channels which can be authenticated by human users. They can, therefore, be used to form the basis of a pairing operation. Recently proposed pairing protocols and methods 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 show how strong mutual authentication can be achieved even with a unidirectional visual channel, where prior methods could provide only a weaker property termed as presence. This could help reduce the execution time and improve usability of prior pairing methods. In addition, by adopting recently proposed improved pairing protocols, we propose how visual channel authentication can be used even on devices that have very limited displaying capabilities, all the way down to a device whose display consists of a cheap single light-source, such as a light-emitting diode. We present the results of a preliminary usability study evaluating our proposed method.

“配对”是在无线渠道上建立认证的关键协议。但是，基于双向物理通道，各种配对的场景本质上是不对称的，即在两个设备之间存在单向物理通道（例如，在手机和访问点之间）并通过采用最近提出的配对协议来提高先前的配对方法，我们提出了如何在显示功能非常有限的设备上使用视觉通道身份验证，一直以廉价的单一来源为单位。