Jamming attacks and Anti-Jamming Strategies on Car Remote Keyless Entry System

This research investigated the jamming attacks on car Remote Keyless Entry (RKE) systems based on the computed signal to noise ratio (SNR) and then proposed, an anti-jamming strategy from the analysis of the results. The increasing misuse of small portable radio frequency electronic devices to transmit unlawful intentional signals is responsible for interfering with the operation of a radio frequency-based car remote central locking system known as RKE system. It contains a short-range radio transmitter (key fob) and a receiver unit inside the vehicle, with most RKEs operating at frequency of 315 MHz for North American cars and at 433.92 MHz for European. The effect of this jamming signal on the RKE will depend on some factors including but not limited to transmitter power, the relative transmitters distances from the car. In the simplest form of RKE jamming, the radio frequency signal from the jammer corrupts the content of the radio frequency signal from the car key fob transmitter within the RKE proximity so that the intended receiver wrongly decodes the message to close the car door. In this investigation, two signals, one from a gate motor remote (jammer) located at a fixed distance from the car and the second from a car key fob located at distance not exceeding the car locking distance were transmitted to a car equipped with an RKE system concurrently. The SNR at the RKE receiver was computed using the appropriate propagation model. This process was repeated for different locations or distances of the car key fob. A matrix of SNR values for different pairs of, car key fob/jammer. The transmission parameters like transmission frequency, transmission power as well as transmitted signal bandwidth of the transmitters that were not available were determined through measurements using a spectrum analyser. Based on the SNR data obtained, the area of the likelihood of jamming was determined and the necessary conclusions and proposals are given.