Gone in 60 seconds–the high-tech version

First introduced in the 1980s, modern remote keyless entry systems use a circuit board, a coded Radio-Frequency Identification (RFID) technology chip, a battery, and a small antenna; the latter two designed so that the fob can broadcast to a car while it's still several feet away. The RFID chip in the key fob contains a select set of codes designed to work with a given car. These codes are rolling 40-bit strings, meaning that with each use, the code changes slightly, creating about 1 trillion possible combinations in total. When you push the unlock button, the keyfob sends a 40-bit code along with an instruction to unlock the car doors; if the synced-up car receiver gets the 40-bit code it is expecting, the car performs the instruction. If not, car does not respond. §