lock and key

Devices that provide security, usually fitted to a door of some kind. In 1778 English locksmith Robert Barron made the forerunner of the mortise lock, which contains levers that the key must raise to an exact height before the bolt can be moved. The Yale lock, a pin-tumbler cylinder design, was invented by US locksmith Linus Yale, Jr, in 1865. More secure locks include combination locks, with a dial mechanism that must be turned certain distances backwards and forwards to open, and time locks, which are set to be opened only at specific times.

Locks originated in the Far East over 4,000 years ago. The Romans developed the warded lock, which contains obstacles (wards) that the key must pass to turn.