Evaluation of Ad-hoc Secure Device Pairing Method with Accelerometer and Camera Using Marker

Abstract

Currently, devices with wireless technologies often communicate each other ad hoc. For example, a presenter wirelessly distributes ad-hoc meeting materials from a PC to mobile device in a meeting room. However, there is a problem of spoofing by an impersonator outside the room. Hence, devices must conduct secure pairing, which is exchange of key necessary for encrypting communication contents, before the communication. As a pairing method between devices, there are pairing methods using RSS from access point as features. However, RSS changes significantly due to environmental factors. On the other hand, there are the pairing methods which compare acceleration data from devices with displacement data of devices from camera of a server. However, these methods have problems that it is necessary to use infrared camera and difficult to recognize inclination of devices. Thus, these methods cannot perform accurate device pairing. Therefore, in this paper, we propose a method that perform pairing using devices' accelerometers and markers displayed on devices, and a camera of authentication server. This method performs pairing by calculating similarity between velocity data from acceleration data from devices and displacement data of the marker from camera after comparing marker sequence displayed on the device. This method has advantage that can detect devices' inclination by recognizing markers' inclination. We performed three types of experiments to confirm the similarity of displacement data and acceleration data, whether an impersonator outside camera range can perform pairing, and possibility of several devices pairing together. As a result, we founded that the larger the device's display is, the higher the similarity, the proposed method can distinguish legitimate user from impersonator outside camera range by average similarity, and three devices succeeded pairing at rate of 71.8%.