The first major development in improving the security of locks came in 1778, when Robert Barron invented what is known as the Barron lock. This design was then improved on in 1818 by Jeremiah Chubb, so that the lock was resistant to lock-picking, and, furthermore, could show if there had been a lock-picking attempt.

A house key or residential door key will have a code like "LR-2" or "SR-1" on the head. Take the key to a hardware store and ask the key maker if they know what the letter and number designation on the key signifies. Keys usually are coded by type of lock they fit and this could identify old keys.

A series of pointed teeth and notches on the blade, called bittings, then allow pins to move up and down until they are in line with the shear line of the inner and outer cylinder, allowing the cylinder or cam to rotate freely and the lock to open.

The blade is the specific part of the key which slides inside the lock. The bow is the portion which protrudes from the blade; the part you hold in your hand when you use the key. *Some of the keyways offered. A Kwikset keys, for example, will always fit in a Kwikset lock, even if it won't turn.