A tamper proof locking mechanism incorporating a first fixture for attachment to an index protective cover, a second fixture for attachment to an instrument, and a third fixture for connecting the first fixture to the second fixture. The first fixture may have a receptacle, the second fixture may have a plate with an opening, and the third fixture may have a protrusive structure that fits into the receptacle of the first fixture and into the opening in the plate to connect the first fixture to the second fixture. The protrusive structure may have a rivet that is partially embedded with a plastic-like material that reveals tampering when an attempt is made to break a connection between the first fixture and the second fixture.