Electronic Key System Relay Attack Prevention
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Solution Overview
Problem
Existing electronic key systems with smart keyless functions are vulnerable to relay attacks, especially when there are multiple electronic keys for a single vehicle, as previously proposed countermeasures may not effectively disable the smart keyless function for all keys.
Innovation Solution
The system introduces a normal and deactivated mode for both the vehicle-mounted device and electronic keys, where successful communication is required for normal mode operation but inhibited in deactivated mode, preventing relay attacks by ensuring that at least one component is in deactivated mode.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the smart keyless function is temporarily deactivated by using a certain electronic key to cope with relay attack, then relay attack countermeasure is improved, but the countermeasure fails to effectively work for remaining electronic keys
Solution Approach 1:
The patent merges the deactivated mode state across multiple electronic keys and the vehicle-mounted device. When any electronic key is in deactivated mode, the vehicle-mounted device detects this state and prevents authentication for all keys, ensuring the countermeasure works system-wide rather than individually for each key.
Solution Approach 2:
The deactivated mode is designed as a universal state that applies to the entire key-vehicle system. The vehicle-mounted device is configured to recognize the deactivated mode from any electronic key and enforce the countermeasure universally, making the system adaptable to multiple keys while maintaining security.
2Ease of operation
If the vehicle-mounted device receives a reply signal from the electronic key after transmitting a radio signal, then given processing is permitted to be executed in normal mode, but the device cannot distinguish between legitimate communication and relay attack
Solution Approach 1:
The patent applies preliminary anti-action by introducing a deactivated mode that proactively prevents communication before relay attack can succeed. When the electronic key or vehicle-mounted device is in deactivated mode, the authentication process is blocked in advance, preventing the relay attack from completing even though the communication protocol itself remains unchanged.
Solution Approach 2:
The deactivated mode acts as an intermediary state that mediates between normal operation and security protection. It introduces a control layer that can intercept and block authentication attempts without modifying the underlying communication protocol, allowing the system to maintain ease of operation while preventing relay attacks.
Data Source
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AI summary
Disclosed is an electronic key system 1 which comprises a vehicle-mounted device 10 and a plurality of electronic keys 30 (30A, 30B), and is configured to have: a normal mode in which given processing is permitted to be executed by the vehicle-mounted device 10 when given wireless communication processing between the vehicle-mounted device 10 and any one of the plurality of electronic keys 30 is successfully completed; and a deactivated mode in which the given processing is inhibited from being executed by the vehicle-mounted device 10. The vehicle-mounted device 10 is configured not to execute, in the deactivated mode, the given processing even when receiving an RF signal after transmitting an LF signal, during the given wireless communication processing, and the one electronic key 30 is configured not to transmit, in the deactivated mode, the RF signal even when receiving the LF signal, during the given wireless communication processing.