A secure and effective device pairing protocol

The need to secure communications between personal devices is increasing nowadays, especially in the context of Internet of Things. Authentication between devices which have no prior common knowledge is a challenging problem. One solution consists in using a pre-authenticated auxiliary channel, human assisted or location limited, usually called out-of-band channel. A large number of device pairing protocols using an out-of-band channel were proposed. However most of these propositions lacks a formal analysis, and therefore may be vulnerable to some attacks. In this paper, we introduce a new key agreement protocol between two wireless devices. This protocol, only using two wireless messages and one out-of-band message, offers better communication costs than currently existing solutions, yet still ensuring a reasonable security. Security of our proposal is validated both via a formal proof of the security of our protocol in an extension of the strand space model and an estimation of the attack success probability in a computational model.