Multi-Amplitude Interrogation Signal for Relay Attack Prevention
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Solution Overview
Problem
Passive vehicular entry systems are vulnerable to relay attacks, where thieves relay communication signals to gain unauthorized access by duplicating the interrogation signal, allowing unauthorized access to the vehicle.
Innovation Solution
The system broadcasts an interrogation signal with a first pulse at a first amplitude and a second pulse at a higher amplitude, ensuring that only authorized devices can reproduce the signal, thereby preventing relay attacks by making it difficult for repeater devices to duplicate the original signal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a passive entry system uses a single amplitude interrogation signal, then the system is easier to implement and operate, but it becomes vulnerable to relay attacks where repeater devices can duplicate the signal
Solution Approach 1:
The interrogation signal is segmented into multiple pulses with different amplitudes instead of using a single uniform signal. This segmentation allows the system to encode additional information in the amplitude variations, making it difficult for relay attackers to duplicate the signal without detection.
Solution Approach 2:
The system changes the amplitude parameter of the interrogation signal across different pulses. By varying the amplitude between pulses, the system creates a more complex signal pattern that cannot be easily replicated by repeater devices, thereby enhancing security while maintaining passive operation.
2Reliability
If the system transmits multiple pulses with different amplitudes, then security against relay attacks is enhanced, but the signal transmission complexity increases
Solution Approach 1:
The system uses periodic pulse transmission with varying amplitudes. By transmitting a sequence of pulses at regular intervals with different amplitude levels, the system creates a recognizable pattern that can be validated by the portable device, improving authentication reliability without requiring complex continuous transmission.
Solution Approach 2:
The interrogation signal transitions from a static single-amplitude signal to a dynamic multi-amplitude signal. This dynamic approach allows the system to adapt the signal characteristics, making relay attacks more difficult while managing transmission complexity through structured pulse sequences.
3Object-affected harmful factors
If a repeater device attempts to relay the interrogation signal, then unauthorized access may be gained, but the multi-amplitude signal detection prevents this unauthorized access
Solution Approach 1:
The system implements a feedback mechanism where the portable communication device validates the received signal against the expected multi-amplitude pattern. If the signal does not match the expected pattern (indicating a relay attack), the system can detect and reject the unauthorized access attempt, providing feedback that prevents the harmful action.
Solution Approach 2:
The system takes preliminary anti-action by pre-configuring the interrogation signal with specific amplitude patterns that are difficult to replicate. This preliminary measure prevents relay attacks before they can succeed, as the repeater device cannot easily duplicate the varying amplitude characteristics of the original signal.
Data Source
AI summary
An apparatus and method is provided for identifying unauthorized access to a vehicle having a keyless-passive entry system. An interrogation signal is broadcast from a vehicle based transmission device. The interrogation signal includes a first pulse transmitted at a first amplitude and a second pulse transmitted at a second amplitude where the second amplitude is greater than the first amplitude by at least a predetermined difference threshold. The interrogation signal is received by a portable communication device. A determination is made whether the second amplitude of the second pulse is greater than the first amplitude of the first pulse by a predetermined difference threshold. A determination is made that the interrogation signal is an authorized interrogation signal in response to the determination that the interrogation signal includes the first pulse transmitted at the first amplitude following by the second pulse transmitted at the second amplitude where the second amplitude is greater than the first amplitude by at least a predetermined difference threshold.