On-Vehicle Device Relay Attack Prevention via Dual Antenna Signal Intensity
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Solution Overview
Problem
Existing electronic key systems are vulnerable to relay attacks, where unauthorized third parties can intercept and relay signals between a vehicle and an electronic key, allowing unauthorized access by mimicking the signal intensity pattern.
Innovation Solution
The implementation of an on-vehicle device with first and second antennas, which transmits request signals and measurement signals at different timings, and a mobile device that responds with information on transmission intensities, ensuring that the reception intensities of second measurement signals from both antennas match the specified pattern, thereby preventing unauthorized access.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If signal intensity pattern collation is used to prevent relay attacks, then security against relay attacks is improved, but device complexity increases due to multiple antennas and measurement signals
Solution Approach 1:
The patent divides the signal transmission into multiple segments: request signals, first measurement signals, second measurement signals, and response signals. Each segment serves a specific purpose in the authentication process, allowing the system to verify signal intensity patterns without requiring a single complex signal structure.
Solution Approach 2:
The patent performs preliminary measurements of signal intensities before final authentication. The first measurement signals are transmitted to establish baseline intensity values, and the second measurement signals are used to verify consistency. This preliminary action allows the system to detect relay attacks before granting access.
2Reliability
If multiple measurement signals are transmitted at different timings, then relay attack detection capability is improved, but communication time increases
Solution Approach 1:
The patent uses periodic transmission of measurement signals at different timings to verify signal intensity patterns. By transmitting first measurement signals and then second measurement signals at intervals, the system can detect inconsistencies caused by relay attacks while maintaining a structured communication timeline.
Solution Approach 2:
The patent efficiently processes multiple measurement signals by skipping unnecessary verification steps when signal intensity patterns match expected values. When the first and second measurement signals produce consistent intensity relationships, the authentication process can proceed quickly, reducing overall communication time.
Data Source
AI summary
A transmitter of an on-vehicle device transmits a request signal from a first antenna, and transmits first measurement signals at different timings from the first antenna and a second antenna. The receiver receives a first response signal including information on transmission intensities of a second measurement signals to be transmitted from the first and second antennas. The transmitter further transmits the second measurement signals at different timings from the first and second antennas. The second measurement signals have transmission intensities respectively set based on the information on transmission intensities included in the first response signal. The receiver receives a second response signal transmitted when a relationship between the reception intensities of the second measurement signals transmitted from the first and second antennas agrees with the information on the transmission intensities included in the first response signal.