Abstract: An improved security system for a door that opens inwardly or outwardly, that includes a bar having on one side of the door jamb a U-shaped bracket for locking the bar across the door, preventing its movement inwardly, a double hinge joint on the opposite side, securing the bar to the door jamb, and a key-actuated locking mechanism that includes an actuating fork that raises the security bar at one end away from the U-shaped locking bracket, thereby allowing the door to be opened, and in a second position, disengaging the lever arm from the security bar, causing the security bar to be firmly engaged in the U-shaped lock on the door jamb.