A lock is a physical or electronic fastening device that is released by a physical object ( e.g. key, key card, fingerprint, RFID card, security token, coin, etc). By providing secret information (e.g. number or letter permutation or password) or by combining it, or by being able to be opened on one side, such as a door chain. The key is a device used to operate a lock (e.g. to lock or unlock it). A typical car key is a piece of metal consisting of two components: the bit/blade, slides into the keyway of the car door lock and differeniates between the different keys, and the bow, which is left protruding so that the torque can be applied to the user. In its most straightforward implementation, a key operates a lock or a set of locks that are both locked and locked, a lock / key system where each similarly locked lock needs the same key. The car key fob serves as a security token for access to the locked area; only people who have the correct key can open the lock and access it. Two different keys, one of which is known as the master key, serve to open the lock in more complex mechanical lock / key systems.