RESYNCHRONIZING TRANSMITTERS TO RECEIVERS FOR SECURE VEHICLE ENTRY USING CRYPTOGRAPHY OR ROLLING CODE

摘要

Secret information is stored in the transmitter and receiver of the keyless entry system. The information includes a resynchronization authorization code. When resynchronization is requested by the user pressing the appropriate key fob button, a random number is generated in the transmitter and sent to the receiver along with the resynchronization authorization code. The receiver tests the authorization code received with its stored code. If the codes match, the receiver substitutes the random number received from the transmitter for its existing stored access code, thereby placing the transmitter and receiver back in synchronization.