UWB Passive Entry Distance Verification Against Relay Attacks
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Solution Overview
Problem
Conventional vehicle passive entry systems are vulnerable to relay attacks, which allow unauthorized access and starting of vehicles by extending the range of the key fob's radio frequency signal and intercepting data between the key fob and the vehicle.
Innovation Solution
The implementation of a passive entry system that uses ultra-wideband (UWB) signals for authentication and distance confirmation between the portable fob and the vehicle, including a double-sided UWB ranging session to ensure the fob is within a predetermined distance, thereby preventing unauthorized control of the vehicle functions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If conventional low frequency RFID and UHF transceivers are used for passive entry systems, then the system provides convenient keyless access, but the system becomes vulnerable to relay attacks that extend the transmitter range and intercept data
Solution Approach 1:
The patent introduces UWB transceivers as an intermediary component to establish a separate, secure communication channel for distance verification. This intermediary system uses time-of-flight measurement to independently verify the physical distance between key fob and vehicle, creating a mediator that prevents relay attacks by confirming the fob is within acceptable range rather than just receiving any RF signal
Solution Approach 2:
The patent changes the verification parameter from simple signal presence detection to precise distance measurement using time-of-flight parameters. By measuring the actual physical distance based on signal propagation time, the system transforms the authentication criterion from binary (signal detected/not detected) to continuous (distance within threshold), thereby preventing range extension attacks
2Ease of operation
If the system extends the communication range to allow remote access, then the ease of operation improves, but the security against relay attacks deteriorates
Solution Approach 1:
The patent adds a spatial dimension to the authentication process by implementing three-dimensional distance verification using UWB time-of-flight measurements. Instead of only verifying signal presence in the traditional RF dimension, the system now verifies the physical spatial relationship between fob and vehicle, creating a new dimensional constraint that prevents relay attacks even when signal range is extended
3Reliability
If dual-sided UWB ranging is implemented to verify distance from both fob and vehicle perspectives, then the security against relay attacks improves, but the device complexity increases
Solution Approach 1:
The patent implements a self-verification mechanism where both the fob and vehicle independently calculate and verify the distance measurement. Each side performs the ranging calculation using the time-of-flight data received, creating a self-checking system that mutually validates the distance without requiring a third-party verifier, thereby enhancing security while managing complexity through distributed verification
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This solution enhances the security of vehicle passive entry systems by preventing relay attacks through accurate distance determination and authentication, ensuring only authorized fobs can control vehicle functions, thereby improving the overall security and reliability of the system.
Implementation Method 1
time-of-flight information to confirm the portable fob is within a predetermined distance of the vehicle
Data Source
AI summary
A passive entry system for a vehicle includes a portable fob and a communication and control unit disposed on the vehicle, the communication and control unit configured to control a function of the vehicle. The portable fob and the communication and control unit are configured to communicate ultra-wideband (UWB) signals therebetween. When the function of the vehicle is triggered, the communication and control unit initiates a double-sided UWB ranging session with the portable fob where (i) the portable fob determines a first distance between the portable fob and the communication and control unit, and (ii) the communication and control unit determines a second distance between the portable fob and the communication and control unit. The communication and control unit is configured to prevent control of the function of the vehicle if a final distance, determined from the first and second distances, is greater than the predetermined distance.