If you want to hang a door swinging out, it is easy to secure them. Open the door and drill the hinge and pin from the backside, and drive in a roll pin or tap and set a allenhead screw in the back. The outside of the hinge looks normal, but without access to get that pin out of the hinge pin, it is very hard to remove the door.
to prevent a brute attack with crowbars and such, drill and set a couple of steel dowels in the door that swing into pre-drilled holes on the hinge side. Good luck getting the hinge side out, you could now totally destroy the hinge and still have bank vault action there.
On the strike side, put a steel plate on the door over the bolt area that extends across the jamb. Plate the jamb with a strap, install a 1" or better throw deadbolt, and now it is easier to cut a hole in the wall to get in