New THaW Patent: Proximity Detection with Single-Antenna Device

The THaW team is proud to announce the issuing of a patent for new methods for single-antenna devices to determine proximity between themselves and another device. Previous work in this field provides a method for secure short-range information exchange between a multi-antenna device and a target device. However, a single-antenna device cannot use a multi-antenna-based method and, therefore, has no way to verify its proximity to the target device.

In this patented work, a single-antenna devices uses the phase and/or amplitude of a preamble received from a transmitting device, particularly a repeating portion of the preamble, to determine whether the receiving device is in close proximity to the transmitting device. If the transmitting device is close to the single-antenna device, the repeating portions of the preamble will differ in phase and amplitude, while a large distance between the two will cause the repeating portions to have a substantially consistent phase and amplitude. This can be helpful in preventing a distant adversary from tricking the single-antenna-device into believing that a malformed preamble is a legitimate signal from a nearby device.

Interested in learning more? Check out the patent here!

PIERSON, Timothy J., Ronald Peterson, and David F. KOTZ. System and method for proximity detection with single-antenna device. US 11,871,233 B2, issued January 9, 2024. https://patents.google.com/patent/US11871233B2/en.

Proximity detection with single-antenna IoT devices

ACM SIGMOBILE has posted a video of our presentation of the THaW paper Proximity detection with single-antenna IoT devices at MobiCom’19.  Abstract below the video.

Timothy J. Pierson, Travis Peters, Ronald Peterson, and David Kotz. Proximity Detection with Single-Antenna IoT Devices. In Proceedings of the ACM International Conference on Mobile Computing and Networking (MobiCom), Article #21, October 2019. ACM Press. DOI 10.1145/3300061.3300120.

Abstract: 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.

SNAP: Proximity Detection with Single-Antenna IoT Devices

THaW graduate Tim Pierson will present SNAP, a method for proximity detection with single-antenna IoT devices at MobiCom in October.

SNAP - Likelihood of declaring proximityAbstract: 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.

In Proceedings of the ACM International Conference on Mobile Computing and Networking (MobiCom), Article #1-15, October 2019. ACM Press. DOI 10.1145/3300061.3300120.

Securing the life-cycle of Smart Environments (video)

This one-hour talk by David Kotz was presented at ARM Research in Austin, TX at the end of January 2019.  The first half covers some recent THaW research about Wanda and SNAP and the second half lays out some security challenges in the Internet of Things.  Watch the video below.

Abstract: The homes, offices, and vehicles of tomorrow will be embedded with numerous “Smart Things,” networked with each other and with the Internet. Many of these Things interact with their environment, with other devices, and with human users – and yet most of their communications occur invisibly via wireless networks.  How can users express their intent about which devices should communicate – especially in situations when those devices have never encountered each other before?   We present our work exploring novel combinations of physical proximity and user interaction to ensure user intent in establishing and securing device interactions. 

What happens when an occupant moves out or transfers ownership of her Smart Environment?  How does an occupant identify and decommission all the Things in an environment before she moves out?  How does a new occupant discover, identify, validate, and configure all the Things in the environment he adopts?  When a person moves from smart home to smart office to smart hotel, how is a new environment vetted for safety and security, how are personal settings migrated, and how are they securely deleted on departure?  When the original vendor of a Thing (or the service behind it) disappears, how can that Thing (and its data, and its configuration) be transferred to a new service provider?  What interface can enable lay people to manage these complex challenges, and be assured of their privacy, security, and safety?   We present a list of key research questions to address these important challenges.