Secure Association for the Internet of Things

Abstract. Existing standards (ZigBee and Bluetooth Low Energy) for networked low-power wireless devices do not support secure association (or pairing) of new devices into a network: their association process is vulnerable to man-in-the-middle attacks. This paper addresses three es-sential aspects in attaining secure association for such devices. First, we define a user-interface primitive, oblivious comparison, that allows users to approve authentic associations and abort compromised ones. This distills and generalizes several existing approve/abort mech-anisms, and moreover we experimentally show that OC can be imple-mented using very little hardware: one LED and one switch. Second, we provide a new Message Recognition Protocol (MRP) that allows devices associated using oblivious comparison to exchange au-thenticated messages without the use of public-key cryptography (which exceeds the capabilities of many IoT devices). This protocol improves upon previously proposed MRPs in several respects. Third, we propose a robust definition of security for MRPs that is based on universal composability, and show that our MRP satisfies this defini-tion.