Abstract: A tamper-proof fastener provided with a threaded shank and a low-profile drive head integral therewith. The drive head has a generally frusto-conical shape defining a circular flat top and a circular base of larger diameter, three short noses separated 120 degrees apart projecting from the sloped side of the drive head. The fastener is installed in a substrate or withdrawn therefrom by means of a tool having a driver head provided with a complementary frusto-conical socket to accommodate the drive head of the fastener, the wall of the socket having recesses therein to receive the noses of the head whereby a torque may be applied thereto.