Saab Keyless Entry Remote

This invention relates generally to an encryption process for a remote keyless entry system and, more particularly, to an encryption process for a remote keyless entry system that includes a rolling code updating scheme that provides heightened security integrity against unwanted entry.  

The Saab remote keyless entry system enables a vehicle operator to perform certain functions, such as lock or unlock a door or trunk of the vehicle, from a remote location are known in the art. Keyless entry systems of this type generally include a portable transmitter carried by the vehicle operator, usually included as part of a fob attached to a key chain for carrying keys of the vehicle. The transmitter will include a button that, upon activation, will cause the transmitter to broadcast a radio frequency signal as a series of coded data bits. If the vehicle is within the operating range of the transmitter, an antenna and receiver associated with the vehicle will receive the coded signal. If the receiver determines the coded signal to be valid, then the receiver will automatically cause the desired function to be performed as encoded on the signal.