Locksmiths fix broken locks, make keys, and install security systems like alarms. In most countries locksmiths must follow a strict set of laws. In some countries locksmiths start as apprentices. In others, they must get a certificate or degree after training at a school or university. Locksmiths commonly work with all types of locks. Other areas that locksmiths cover include combination locks, auto locksmithing, safes, and access control. These areas are specialist and require specialized training.
https://simple.wikipedia.org/wiki/Locksmith