Keyfob Accelerometer Relay Attack Detection
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Automotive keyless entry systems, particularly Passive Entry/Passive Start (PEPS) systems, are vulnerable to 'relay attacks' where thieves can unlock and potentially steal a vehicle without the owner's awareness by using devices to amplify and relay wireless signals, making it difficult to distinguish between the vehicle and a legitimate keyfob.
Innovation Solution
A keyfob with an integrated accelerometer that measures acceleration data and received signal strength indicator (RSSI) to detect potential attacks, disabling the wake receiver when stationary and out of range, and comparing calculated distances from RSSI and acceleration data to determine if an attack is occurring, thereby preventing unauthorized access.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the wake receiver is continuously enabled to receive wireless signals, then the system can respond to legitimate keyfob signals, but the system becomes vulnerable to relay attacks where thieves can amplify and relay signals from distant locations
Solution Approach 1:
The wake receiver transitions from a static continuously-enabled state to a dynamic state that is selectively enabled only when motion is detected. The accelerometer continuously monitors for motion, and when motion exceeding a threshold is detected, the wake receiver is activated. This dynamic approach ensures the receiver is active only when needed (when the keyfob is being carried/moved), reducing vulnerability to relay attacks while maintaining responsiveness to legitimate use.
Solution Approach 2:
The system performs preliminary motion detection via the accelerometer before enabling the wake receiver. By continuously monitoring acceleration and detecting motion in advance, the system prepares to receive wireless signals only when the keyfob is likely to be in use, preventing premature or unauthorized activation that could enable relay attacks.
2Reliability
If the wake receiver is disabled when stationary to prevent attacks, then security is improved, but legitimate access may be delayed when the keyfob is placed down temporarily
Solution Approach 1:
The system uses the accelerometer to detect mechanical motion (vibration, movement, being carried) as the trigger for enabling the wake receiver. This motion-based trigger ensures the receiver is activated when the keyfob is in use (being carried around) and disabled when stationary, providing a natural and intuitive operation mode that balances security with convenience.
Solution Approach 2:
The keyfob autonomously determines when to enable or disable the wake receiver based on its own motion state detected by the integrated accelerometer. The system self-regulates its security state without requiring user intervention, automatically enabling protection when stationary and allowing access when motion is detected, simplifying the user experience while maintaining security.
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
Effectively thwarts relay attacks by ensuring the wake receiver is only enabled when the keyfob is in motion within the vehicle's wireless range, reducing the likelihood of unauthorized vehicle access and enhancing security.
Implementation Method 1
an accelerometer to generate acceleration data based on motion of the keyfob
Implementation Method 2
a wake receiver to receive wireless signals from the vehicle and to measure the received signal strength (the resulting measured value called the received signal strength indicator (RSSI))
Data Source
AI summary
A keyfob is disclosed for use in detecting an attack on a vehicle. The keyfob includes a microcontroller, a wake receiver and an accelerometer. The wake receiver is configured to measure received signal strength and save the measured value in received signal strength indicator (RSSI). The accelerometer is used to generate acceleration data. The microcontroller detects an attack based on the RSSI and the acceleration data.