Jeff Kaul, 341st Civil Engineer Squadron locksmith, places tumblers back into a lock during a re-keying Feb. 3, 2015, at Malmstrom Air Force Base, Mont. Whenever a new key is needed for a building’s door, Kaul has to re-key the lock to make it compliant with the new key. (U.S. Air Force photo/Airman 1st Class Dillon Johnston)