Portable Electronic Key Motion Detection Relay Attack Prevention
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Solution Overview
Problem
Existing electronic key systems are vulnerable to relay attacks, where unauthorized communication is made using a relay, leading to invalidation of the portable electronic key device's functionality when the user is stationary, causing inconvenience and security concerns.
Innovation Solution
A portable electronic key device equipped with a motion detector, key function controller, communication monitoring unit, and operation controller that enables predetermined functions only upon movement detection, maintains functionality even when movement stops, and resets timers upon radio wave reception, preventing unauthorized communication and ensuring convenience and security.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the portable electronic key device uses acceleration sensor to detect movement for security verification, then security against relay attacks is improved, but convenience is worsened when user stands still for long time
Solution Approach 1:
The system dynamically adjusts the functional state of the portable electronic key device based on motion detection. When motion is detected, the device transitions from a disabled state to an enabled state, allowing communication functions to operate. This dynamic state change resolves the contradiction by enabling security verification only when needed (during motion) while maintaining convenience during stationary periods.
Solution Approach 2:
The system changes the operational parameter (enabled/disabled state) of the electronic key device based on motion parameters detected by the acceleration sensor. When motion exceeds a threshold, the device parameter changes from disabled to enabled, allowing communication. This parameter change mechanism allows the device to maintain security during motion while avoiding false disabling during stationary periods.
2Reliability
If the portable electronic key device disables function when acceleration is zero, then security is improved, but usability is worsened during legitimate stationary periods
Solution Approach 1:
The system uses feedback from the acceleration sensor to continuously monitor motion state and adjust the functional enable/disable status accordingly. The feedback loop ensures that the device remains enabled during legitimate stationary periods (such as when a user is standing still near their vehicle) while disabling only during suspicious stationary periods that indicate potential relay attacks.
Solution Approach 2:
The system performs preliminary motion detection and analysis before disabling the electronic key function. By monitoring acceleration patterns and determining whether zero acceleration represents a legitimate stationary state or a potential security threat, the system avoids premature disabling of functions during normal stationary periods.
3Reliability
If the device requires continuous movement detection to maintain function, then security against unauthorized communication is improved, but device complexity increases
Solution Approach 1:
The system extracts only the essential motion detection capability from the acceleration sensor to determine functional enable/disable state, rather than implementing complex continuous monitoring algorithms. By taking out the core motion detection function and using it to trigger simple enable/disable transitions, the system maintains high security while minimizing device complexity.
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
The solution effectively prevents unauthorized communication, maintains device functionality during user inactivity, and ensures immediate communication reestablishment, enhancing both security and convenience by using motion detection and radio wave monitoring.
Implementation Method 1
a motion detector configured to detect movement of the portable electronic key device
Implementation Method 2
wirelessly transmits an electronic key ID and a lock side communication device that performs verification of the electronic key ID
Data Source
Figure 1
Figure 2~3
Figure 4
AI summary
A portable electronic key device 2 starts up only when movement of the portable electronic key device 2 is present on the basis of detection signal Sac of a motion detector 27. A communication monitoring unit 29 monitors whether or not radio waves Swk periodically transmitted from a vehicle 1 are received. When there is no movement of the portable electronic key device 2 but the portable electronic key device 2 has received or is receiving radio waves from the vehicle 1, an operation controller 30 maintains the start-up state of the portable electronic key device 2.