Keyless Entry Proximity Detection Against BLE Relay Attacks
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Solution Overview
Problem
Passive keyless entry systems are vulnerable to relay attacks where intruders mimic the proximity of the key fob to the vehicle using signal relaying, compromising security.
Innovation Solution
A system utilizing both low frequency (LF) and Bluetooth Low Energy (BLE) signals to measure distance and activity patterns, incorporating a microcontroller to determine the key fob's proximity and filter noise, thereby preventing relay attacks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If low frequency communication is used for keyless entry, then ease of operation is improved, but security is worsened due to relay attack vulnerability
Solution Approach 1:
The patent introduces Bluetooth Low Energy (BLE) as an intermediary communication channel between the key fob and vehicle. The BLE module establishes a separate communication path that enables the vehicle to receive additional data from the key fob, which is then used to verify legitimate proximity through multiple signal strength measurements. This intermediary system prevents relay attacks while maintaining the convenience of keyless entry.
2Ease of operation
If signal strength measurement is used to determine proximity, then ease of operation is improved, but measurement precision is worsened due to noise and relay attacks
Solution Approach 1:
The system implements feedback by continuously measuring signal strength at multiple time points and comparing these measurements to determine key fob proximity. The microcontroller performs sequential measurements and uses the feedback from these measurements to verify whether the key fob is legitimately close to the vehicle or being relayed, thereby improving measurement precision while maintaining automatic operation.
Solution Approach 2:
The patent employs periodic action by taking multiple signal strength measurements at different time points (first, second, and third measurements at different times). This temporal sampling approach allows the system to detect anomalies that would indicate relay attacks, significantly improving proximity detection accuracy compared to single-point measurements.
3Reliability
If multiple measurement time points are used to prevent relay attacks, then security is improved, but loss of time is worsened
Solution Approach 1:
The system performs preliminary action by continuously monitoring BLE signal strength in the background even when the vehicle is not actively attempting to access the key fob. This preliminary monitoring ensures that when authentication is needed, the system already has baseline data to quickly compare against new measurements, reducing the time penalty for security verification while maintaining relay attack prevention.
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
Enhances security by accurately determining the key fob's proximity and thwarting relay attacks, ensuring secure vehicle access operations.
Implementation Method 1
measuring a strength of a signal transmitted from the electronic key
Data Source
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AI summary
A system for performing an operation in a vehicle is disclosed. The system includes a Bluetooth Low Energy (BLE) module, a microcontroller coupled to the BLE module and a transmitter/receiver coupled to the microcontroller. The microcontroller is configured to transmit a wakeup signal at preselected intervals to wake up an electronic key and measure received low frequency (LF) signal strength and Bluetooth signal strength transmitted from the electronic key and based on measured signal strengths determine if the electronic key is approaching the vehicle and to perform a preselected vehicle operation on the vehicle.