For anyone who’s interested in this, it’s called impressioning and is really cool. It basically uses the design of the lock (pins pushed down into the keyway by

For anyone who’s interested in this, it’s called impressioning and is really cool. It basically uses the design of the lock (pins pushed down into the keyway by springs, preventing the cylinder from turning) in the attack by using the marks those pins make on a key, to gradually fashion a working key.