Message Time of Arrival Codes: A Fundamental Primitive for Secure Distance Measurement

Abstract

Secure distance measurement and therefore secure Time-of-Arrival (ToA) measurement is critical for applications such as contactless payments, passive-keyless entry and start systems, and navigation systems. This paper initiates the study of Message Time of Arrival Codes (MTACs) and their security. MTACs represent a core primitive in the construction of systems for secure ToA measurement. By surfacing MTACs in this way, we are able for the first time to formally define the security requirements of physical-layer measures that protect ToA measurement systems against attacks. Our viewpoint also enables us to provide a unified presentation of existing MTACs (such as those proposed in distance-bounding protocols and in a secure distance measurement standard) and to propose basic principles for protecting ToA measurement systems against attacks that remain unaddressed by existing mechanisms. We also use our perspective to systematically explore the tradeoffs between security and performance that apply to all signal modulation techniques enabling ToA measurements.

Security analysis of IEEE 802.15.4z/HRP UWB time-of-flight distance measurement

“…In such a configuration, and when combined with distance commitment and distance bounding, LRP mode can support a secure ranging systems [14,28]. The proposals to secure LRP for longer distances and severe NLOS have been proposed in [22,27]. Unlike LRP, HRP, on the other hand, has lower power per pulse; as a result, the receiver cannot detect individual pulses for ToA estimation and data detection.…”

“…Recently, the research community has suggested the term Message Time of Arrival Codes (MTAC) as a theoretical notion for secure distance estimation and ranging based on ToF measurements [22]. A ranging system is deemed secure if it can provide secure MTAC construction: physical-layer message codes that allow the receiver to verify the message time of arrival securely.…”

Experimental Evaluation of IEEE 802.15.4z UWB Ranging Performance under Interference

“…While the Institute of Electrical and Electronics Engineers (IEEE) 802.15.4a-2015 standard [20] suffers from not providing methods to counter these synchronization issues, the newly introduced IEEE 802.15.4z-2020 standard [21] provides measures to reduce these effects. Next to many improvements in the allowable Physical Layer (PHY) configuration [22,23] and reduced ranging times [24], another cryptographic spreading sequence, Scrambled Time Sequence (STS) is introduced to detect and mitigate erroneous TOA estimation [25][26][27].…”

Toward a secure crowdsourced location tracking system

“…In practice, a CD (proxy) could serve as a relay to a TD and could enable other CDs to communicate with the TD without being in BLE proximity. Although techniques such as distance bounding [21], secure distance measurement [41], or an out-of-band hardware token [19] could be used to prevent these attacks, the low energy requirement of the TDs makes the existing solutions impractical.…”