Ordinary screws can be adapted to make them burglar-proof – a particularly necessary precaution when screwing down timber-framed rooflights. First drill pilot holes for the screws and insert them into the holes in the normal way, stopping just short of the final tightening turns.
Remove the screws, noting the edges of the screw slots which take the pressure. File these edges off, then reinsert the screws and tighten them fully. Because there is no edge for the screwdriver to bite on in an anticlockwise direction, the screws can never be undone once they have been fixed.