Ranging Protocol Security via Transmission Time Randomization
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Solution Overview
Problem
IEEE 802.11az ranging protocols are vulnerable to eavesdropping, as measurement reports sent over the air can be intercepted, allowing eavesdroppers to calculate the distance between ranging devices, compromising user privacy and security.
Innovation Solution
Implementing protection mechanisms such as randomizing the transmission time of sounding signals and measurement reports, using cyclic shift diversity, and scrambling channel state information to prevent eavesdroppers from determining the exact location of devices, while ensuring that legitimate devices can still calculate the round-trip time correctly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If measurement reports are transmitted openly for ranging functionality, then ranging accuracy is improved, but security and privacy are compromised due to eavesdropping
Solution Approach 1:
The patent applies parameter changes by modifying the transmission time parameter of sounding signals and measurement reports. By randomizing the transmission time, the system maintains ranging functionality while preventing eavesdroppers from accurately determining device locations through timing analysis of open measurements
Solution Approach 2:
The patent introduces an intermediary protection mechanism that obscures the direct relationship between measurement reports and device locations. The randomization acts as an intermediary layer that preserves the utility of open measurements for legitimate ranging while blocking eavesdropping attempts
2Object-affected harmful factors
If transmission time is randomized for security protection, then eavesdropping resistance is improved, but ranging calculation complexity increases
Solution Approach 1:
The patent modifies the time parameter by introducing randomization, which increases eavesdropping resistance. The complexity increase is managed by maintaining the fundamental ranging calculation logic while adding randomization layers that do not fundamentally alter the measurement report structure or calculation methods
3Object-affected harmful factors
If measurement reports are protected from eavesdropping, then user privacy is improved, but open measurement functionality is reduced
Solution Approach 1:
The patent applies parameter changes to transmission timing while preserving the open measurement functionality. The measurement reports remain accessible and usable for legitimate ranging purposes, but the randomized timing parameter prevents eavesdroppers from exploiting the open measurements to determine precise device locations
Solution Approach 2:
The patent converts the vulnerability of open measurements into a benefit by using the same open measurement framework but adding randomization. This transforms the previously harmful openness into a protective feature, where the measurable signals remain available for legitimate use but become unusable for eavesdropping purposes
Data Source
AI summary
Methods, apparatus, and computer-readable media are described to encode a trigger frame for a second station (STA2). A first sounding frame for the STA2 is generated. The first timestamp is associated with a transmission of the first sounding frame. A second sounding frame from the STA2 based upon the first sounding frame is decoded. The second sounding frame includes a holding time indication associated with a second timestamp and a third timestamp. A fourth timestamp is associated with receiving the second sound frame. The holding time indication is protected. A round-trip time is calculated based upon the first timestamp, the holding time indication, and the fourth timestamp.