Mechanical or electronic fastening device A typical modern padlock and its keysĪ lock is a mechanical or electronic fastening device that is released by a physical object (such as a key, keycard, fingerprint, RFID card, security token or coin), by supplying secret information (such as a number or letter permutation or password), by a combination thereof, or it may only be able to be opened from one side, such as a door chain.Ī key is a device that is used to operate a lock (to lock or unlock it).
