Secure Pairing of Mobile Devices

As mobile devices become increasingly popular, the necessity for both user-friendly and secure pairing methods for these devices also rises. One natural approach to pairing devices is to match them based on a shared experience. In this work, we define a shared experience as the act of physically holding two devices together and shaking them for a short period. The common movement data collected during the shaking process can subsequently be used to verify the authenticity of a secret key established via a key exchange protocol. This paper explores the process of key verification using two different measures: a coherence measure derived through time series analysis and a measure based on Hamming distance. Using ROC curves, we show that both of these measures robustly distinguish between the case where two devices have been shaken together and the case where two devices have been shaken separately.