Method for protecting a passive keyless entry system against a relay attack
AssigneeNXP B.V.
InventorJAN-PETER SCHAT
Life of this patent
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Abstract
A method is provided for authenticating a transceiver in a keyless entry system for a vehicle. The method uses a collision avoidance radar system on the vehicle for authenticating a key fob radar transceiver. A lower power radar signal is transmitted from the vehicle. The lower power radar signal is transmitted below an ambient noise level to make the radar signal difficult for an attacker to detect. The key fob transceiver is then authenticated as being a legitimate transceiver for accessing the vehicle using the low power radar signal. A distance bounding scheme may be used to determine if the key fob is within a predetermined distance. Challenge/response communications may be used to authenticate that the key fob is the legitimate key fob.
Claims20
A method for authenticating a transceiver in a keyless entry system for a vehicle, the method comprising:
- transmitting a low power radar signal from the vehicle, wherein the low power radar signal is transmitted below an ambient noise level;
- and
- authenticating that the transceiver is a legitimate transceiver for accessing the vehicle using the low power radar signal, wherein transmitting the low power radar signal comprises reducing a transmit power of a collision avoidance radar signal to a level below the ambient noise level by switching off a power amplifier used for amplifying the collision avoidance radar signal and transmitting the reduced power collision avoidance radar signal as the low power radar signal.
A method for authenticating a transceiver in a keyless entry system for a vehicle, the method comprising:
- attenuating a collision avoidance radar signal generated on the vehicle to produce a low power radar signal having a power level below an ambient noise level, wherein the collision avoidance radar signal is attenuated by switching off a power amplifier used to amplify the collision avoidance radar signal for transmission;
- transmitting the low power radar signal from the vehicle in response to a signal received from the transceiver;
- and
- using the low power radar signal, authenticating that the transceiver is a legitimate transceiver for accessing the vehicle.
A method for authenticating a transceiver in a keyless entry system for a vehicle, the method comprising:
- attenuating a 77 GHz collision avoidance radar signal generated on the vehicle to produce a low power radar signal having a power level below an ambient noise level, wherein attenuating a collision avoidance radar signal comprises switching off a power amplifier used to amplify the collision avoidance radar signal for transmission;
- transmitting the low power radar signal from the vehicle in response to a signal received from the transceiver;
- using the low power radar signal, authenticating that the transceiver is a legitimate transceiver for accessing the vehicle using the low power radar signal to determine that a distance between the vehicle and the transceiver is less than predetermined distance;
- and
- authenticating that the transceiver is a legitimate transceiver using the low power radar signal to communicate with the transceiver using spread spectrum challenge/response messages.
Dependencies are inferred from the claim text.