Vehicle Access System Inverting Wake-Up Sequence for Relay Attack Prevention

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Solution Overview

Problem

Current passive keyless entry (PKE) systems are vulnerable to relay station attacks, where unauthorized individuals can intercept and relay communication between a car and its key, allowing unauthorized access and starting of the vehicle without the key holder's knowledge, due to the simplicity of existing PKE systems.

Innovation Solution

The secure vehicle access system reverses the wake-up mechanism by configuring the key to wake up the vehicle, eliminating the need for costly low-frequency transmission circuits and using a low-power RF link combined with ultra-wideband ranging to determine access, thereby transferring decision-making away from the vehicle and incorporating a time-discontinuous operation to minimize battery impact.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the vehicle uses a simple PKE system with LF transmission and RF reception, then the system is easy to operate and has low device complexity, but the system becomes vulnerable to relay station attacks and loses security

Engineering Contradiction:
Improveease of operationVSAvoidsecurity
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The patent inverts the traditional wake-up mechanism by having the key initiate the communication sequence instead of the vehicle. The key broadcasts a wake-up signal and waits for vehicle acknowledgment, which prevents relay attacks because the vehicle's response can be verified for authenticity and timing, ensuring the key is physically present rather than being relayed from a remote location.

Inventive Principle:
Principle #13The other way round (Inversion)

2Reliability

If the system adds precise distance measuring operations using UWB or IR to prevent relay attacks, then the security is improved, but the device complexity and cost increase significantly

Engineering Contradiction:
ImprovesecurityVSAvoiddevice complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent uses the existing RF communication channel as an intermediary to achieve security without adding complex distance measuring hardware. By embedding security verification within the RF wake-up and acknowledgment sequence, the system achieves relay attack prevention using the existing communication infrastructure rather than requiring separate UWB or IR distance measurement systems.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Ease of operation

If the key continuously monitors for vehicle signals, then the response time is fast and ease of operation is maintained, but the battery consumption increases

Engineering Contradiction:
Improveease of operationVSAvoidbattery consumption
Core Design Contradiction:
Ease of operationVSUse of energy by moving object

Solution Approach 1:

The patent implements periodic action by having the key broadcast wake-up signals at intervals rather than continuously monitoring. The key initiates communication only when needed (periodically or on-demand), and the vehicle responds with acknowledgment signals. This approach maintains fast response times while significantly reducing battery consumption compared to continuous monitoring.

Inventive Principle:
Principle #19Periodic action

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 approach significantly reduces the risk of relay station attacks by making it difficult for thieves to control vehicle access, even when the key is far from the vehicle, while also extending battery life through minimal power consumption.

Implementation Method 1

The key further includes a ranging circuit configured to perform a distance determination between the vehicle and the key, following the establishment of the communication link

Methodology Applied
Scientific EffectTime of flight: Time of Flight

Implementation Method 2

a number of ultra-wideband (UWB) communication transceivers configured to use a very low energy level for short-range, high-bandwidth communications over a large portion of the radio spectrum

Methodology Applied
Scientific EffectElectromagnetic radiation: Electromagnetic Induction

Data Source

PatentEP3335942B1Secure vehicle access system, key, vehicle and method therefor
Publication Date: 2019.11.20 NXP BV
  • EP3335942B1 patent drawingFigure 1
  • EP3335942B1 patent drawingFigure 2
  • EP3335942B1 patent drawingFigure 3~4

AI summary

A secure vehicle access system (500) comprises a vehicle (510) and a key (520) associated with the vehicle (510). The key (520) comprises: a radio frequency, RF, key transceiver (534) configured to: broadcast at least one signal; and listen for an acknowledgement message from the vehicle (510). The vehicle (510) comprises: a radio frequency, RF, vehicle transceiver (517) configured to: listen for the at least one broadcast signal from the key (520); and in response thereto, transmit an acknowledgement message back to the key (520) to establish a communication link between the vehicle (510) and the key (520). The key (520) further comprises a ranging circuit (554) configured to perform a distance determination between the vehicle (510) and the key (520), following the establishment of the communication link, to determine whether to allow access to the vehicle (510).