An extension of the lock and key, keyless entry systems were made possible in the 1970s with the advent of microchip technology. In principle, keyless entry systems are similar to combination locks because they require an alphanumeric code. This code has the advantage of being easily changed to improve security, but like the combination to a lock, must be memorized by the user to be effective. Early versions of keyless entry systems used keypads similar to those found on touch-tone telephones. Later models, using more advanced microchip technology, more closely resemble the keypad on a computer keyboard.

The major innovation in keyless entry systems has been the addition of remote control technology. Using a transmitter inside the remote control unit, locks can be opened from some distance with the press of a button. The remote keyless entry systems have several advantages. They eliminate the need for a keypad and alphanumeric code. In addition, it allows the holder to safely and quickly open a door without fumbling with traditional keys. Not surprisingly, remote keyless entry has found wide application in the automobile industry. Attached to the traditional ignition key, remote controls became virtually a standard feature in automobiles by the mid-1990s. Their use in homes is also expected to expand.