Early RFID systems, both keyless entry (the key fob device with the button you press to unlock the car) and vehicle immobilizers, used 32-bit encryption. That means they sent a code of 32 impulses. With 32 bits in the code, there are billions of possible combinations [source: Stone]. In newer schemes, including remote starters that let you start a car with the push of a button, the codes have 40 bits, which increases the possibilities. With so many possible codes, the system seems unbeatable.