UWBKey: Using Contrastive Learning for Efficient Secure Key Generation in UWB

Ultra-wideband radios are being used for a multitude of localization and ranging applications, from object finding using Apple AirTags, to industrial precise asset localization, to keyless car doors. UWB's ubiquitous presence is fueled, in part, by its effectiveness in separating the wireless signal's first path from multipath and its co-existence with Wi-Fi and other wireless technologies. Yet, today UWB-based devices are still required to be “paired” with a controller device which can gain exclusive access to communicate with that device. This pairing requirement restricts truly ubiquitous and pervasive use-cases for UWB. One of the primary reasons for the pairing requirement is to enable secure UWB communication, including the communication about the ranging parameters and timestamps which then enables secure UWB ranging. Today, this pairing is performed using an out-of-band communication mechanism based on Bluetooth, or Wi-Fi. In this work, we show that an out of band communication is not necessary for establishing secure keys for UWB communication. In fact, the channel impulse response obtained by every UWB device when receiving a packet can itself be leveraged to generate a symmetric secure key. We call our system, UWBKey , and have fully implemented it on a commercial off-the-shelf UWB chip (Qorvo DWM1000). We show that the channel impulse response (CIR) is reciprocal for a pair of communicating devices, and that we can derive a key from the CIR that is close to random. In contrast, an eavesdropper even when nearby cannot obtain the same CIR and therefore cannot infer the key.; AB@This paper develops an important component of the whole UWB ecosystem within the constraints of today's UWB hardware (in terms of available bandwidth), practical environments (in terms of representative public places we could access), and practical device density (with assumptions about how near a malicious device could get). By no means do we believe we have solved the secure communication problem fully, but we are convinced that our open-data, open-hardware, open-software approach in this paper will enable a new thought process among researchers enabling UWB to stand on its own as a secure radio communication and ranging technology, without depending on out-of-band solutions.