I divide locking systems into three classes: 1. Can be opened without tools 2. Can be opened with generic tools (e.g. hammer, hacksaw) 3. Can be opened with

I divide locking systems into three classes: 1. Can be opened without tools 2. Can be opened with generic tools (e.g. hammer, hacksaw) 3. Can be opened with specialized tools (e.g. lock picks, liquid nitrogen)