Abstract: The decoding of a lock, such as a pin tumbler type of lock, is completed by utilizing a method that includes the insertion of a key blank or other material with one or more reference indicators on a modifiable surface, into a keyway of the lock. The key blank is inserted until a stopping resistance is detected. Such a resistance occurs when a pin of the lock reaches a shear line position. After such a position is reached a marking is made on the key blank and a measurement is made. The measurement is compared to markings on a novel decoding template to determine the depth of a cut that should be made on an uncut key.