Proximity Detection with Single-Antenna IoT Devices


Timothy J. Pierson, Travis Peters, Ronald Peterson, and David Kotz. Proximity Detection with Single-Antenna IoT Devices. Proceedings of the ACM International Conference on Mobile Computing and Networking (MobiCom), article 21, 15 pages. ACM, October 2019. doi:10.1145/3300061.3300120. ©Copyright ACM. Revision of pierson:snap-poster.


Providing secure communications between wireless devices that encounter each other on an ad-hoc basis is a challenge that has not yet been fully addressed. In these cases, close physical proximity among devices that have never shared a secret key is sometimes used as a basis of trust; devices in close proximity are deemed trustworthy while more distant devices are viewed as potential adversaries. Because radio waves are invisible, however, a user may believe a wireless device is communicating with a nearby device when in fact the user’s device is communicating with a distant adversary. Researchers have previously proposed methods for multi-antenna devices to ascertain physical proximity with other devices, but devices with a single antenna, such as those commonly used in the Internet of Things, cannot take advantage of these techniques.

We present theoretical and practical evaluation of a method called SNAP -- SiNgle Antenna Proximity -- that allows a single-antenna Wi-Fi device to quickly determine proximity with another Wi-Fi device. Our proximity detection technique leverages the repeating nature Wi-Fi’s preamble and the behavior of a signal in a transmitting antenna’s near-field region to detect proximity with high probability; SNAP never falsely declares proximity at ranges longer than 14 cm.

Citable with [BibTeX]

Projects: [thaw]

Keywords: [authentication] [iot] [security] [wifi]

Available from the publisher: [DOI] [video]

Available from the author: [bib] [pdf]
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[Kotz research]