There are very few safecrackers around, whatever Hollywood might suggest.
Most safes which have attracted the attentions of criminals are carried off and attacked with power tools, in private, over a period of time.
Today’s invention is a coating for safes which consists of irregular, steel protrusions, welded on the outer walls and roof of a safe. These resemble the broken bottles one sees on the top of walls…a major disincentive to even the keenest crook.
Only the keypad and handle would be free of the blades.
Such an approach makes any manhandling of the strongbox (which would be required to get it down stairs, out a window or into a van) almost impossible.
Even wrapping a mattress around or hammering planks onto the blades it would be hazardous, since they would be liable to pierce any such protection when being moved. Anyone foolish enough to attempt entry using explosives would create a cloud of shrapnel.