Vehicle Access Control Module Relay Attack Prevention
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Solution Overview
Problem
Current hands-free vehicle access systems are vulnerable to relay attacks, where unauthorized individuals can unlock and start vehicles from a distance, and existing solutions, such as motion sensors, deactivate the access device if immobile, preventing legitimate users from starting the engine if they are not actively moving the device.
Innovation Solution
A method and device that authenticate the access device with the vehicle's control module, periodically transmit an interrogation signal after unlocking, and set a timeout to prevent deactivation when the device is immobile within the vehicle, ensuring the device remains active for use and inactive only when the user leaves the vehicle, thereby preventing relay attacks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a motion sensor is used to detect device movement and deactivate the access device when immobile, then relay attacks are prevented, but legitimate users cannot start the engine when the device is stationary inside the vehicle
Solution Approach 1:
The system applies different deactivation rules based on the device's location: when outside the vehicle, the device deactivates after a timeout period to prevent relay attacks; when inside the vehicle, the device remains active even when stationary, allowing legitimate engine starting. This location-based differentiation resolves the contradiction between security and usability.
Solution Approach 2:
The access control module on the vehicle acts as an intermediary that receives signals from the access device and determines whether to authorize engine starting based on the device's location and motion state. This intermediary enables the system to distinguish between legitimate stationary use inside the vehicle and potential relay attacks outside the vehicle.
2Object-affected harmful factors
If the access device is deactivated after a timeout period when no motion is detected, then security against unauthorized access is improved, but the device becomes unusable for legitimate purposes when left stationary
Solution Approach 1:
The deactivation timeout period is made dynamic rather than fixed: it applies only when the device is outside the vehicle and adjusts based on the vehicle's detection of the device's presence. When the device is inside the vehicle, the timeout is effectively extended or suspended, allowing the device to remain active for legitimate use while maintaining security when outside.
3Ease of operation
If wireless communication allows access from a distance, then convenience of access is improved, but vulnerability to relay attacks increases
Solution Approach 1:
The system implements preliminary security measures by having the access control module periodically transmit interrogation signals to verify the access device's presence and legitimacy before authorizing engine starting. This preliminary verification prevents relay attacks that would otherwise exploit the convenience of distance-based wireless access.
Data Source
AI summary
A method for securely accessing a motor vehicle whose opening elements are locked and unlocked through wireless communication between a portable access device and an access control module on board the vehicle. The method includes authenticating the device with the access control module, unlocking the vehicle when the device has been authenticated, periodically transmitting, by way of the access control module, an interrogation signal into at least part of the passenger compartment of the vehicle intended for the device following unlocking of the vehicle, upon each reception by the device of said interrogation signal, triggering a first timeout the duration of which is greater than the transmission period of the interrogation signal, and deactivating the device when the first timeout has expired and the immobile state of the device is detected.