Security hardware device with built-in authentication used to control and secure access to mobile devices, automobile, computer systems, network services and data. Also known as a hardware token, a key fob provides on-device, one-factor authentication. Key fobs are among a class of physical security tokens that includes smart cards, proximity cards and biometric keyless entry fobs.
Automobile Key Fob
A remote keyless system using a handheld fob. The functions of a remote keyless entry system are contained on a key fob or built into the ignition key handle itself. Buttons are dedicated to locking or unlocking the doors and opening the trunk or tailgate.
Some remote keyless fobs also feature a red panic button which activates the car alarm as a standard feature. Further adding to the convenience, some cars' engines with remote keyless ignition systems can be started by the push of a button on the key fob (useful in cold weather), and convertible tops can be raised and lowered from outside the vehicle while it's parked.
Radio Frequency
Remote keyless entry fobs emit a radio frequency with a designated, distinct digital identity code. Inasmuch as "programming" fobs is a proprietary technical process, it is typically performed by the automobile manufacturer. In general, the procedure is to put the car computer in 'programming mode'.
Programming mode: usually entails engaging the power in the car several times while holding a button or lever. It may also include opening doors, or removing fuses. The procedure varies amongst various makes, models, and years. Once in 'programming mode' one or more of the fob buttons is depressed to send the digital identity code to the car's onboard computer. The computer saves the code and the car is then taken out of programming mode.
On early (1998–2012) keyless entry remotes, the remotes can be individually programmed by the user, by pressing a button on the remote, and starting the vehicle. However, newer (2013+) keyless entry remotes require dealership or locksmith programming via a computer with special software.