UWB Physical Layer Key Sharing Using the Frequency Domain CIR Magnitude

Abstract

Physical layer key sharing has become a popular topic in today's literature, as it could provide an alternative to computationally expensive key-sharing protocols. Its importance is emphasized by several resource-constrained, battery-powered autonomous robots, and personal devices that must communicate within modern-day industrial complexes. Physical layer key sharing has been explored using temporally and spatially variant characteristics of signals to produce the same secret keys at different devices. In this paper, we propose a novel method for ultra-wideband (UWB)-based physical layer key sharing, leveraging an off-the-shelf plug-and-play UWB module and utilizing the frequency domain of the Channel Impulse Response (CIR) magnitude. The frequency domain effectively aligns and denoises CIR samples, increasing the spatial and temporal uniqueness of channel characteristics. In turn, our approach offers the advantage of creating high-entropy keys with a 92% success rate. Our paper is the first to examine employing an UWB module for key sharing under different dynamic scenarios. Finally, our system maintains a higher level of security against several types of attackers compared to standard CIR methods.