RELAY ATTACK DETECTION OF A SECURE VEHICLE COMMAND COMMUNICATION

摘要

A passive remote entry system evaluates the delay between a challenge signal from security system and a response signal from the passive fob. If the delay exceeds a threshold identification fails and the access is denied. The fob utilizes the signal from the security system as a reference signal for transmitting its response signal. The security system generates a challenge signal with a changing frequency, which is compared to the frequency of the response signal. Any lag in the change of the frequency in the response signal compared to the change in the frequency of the challenge signal is indicative of the amount of delay between the challenge and response signal.