Abstract: A tamper-resistant security lock assembly for use on lockrods of cargo container doors to prevent unauthorized opening of the doors. The lock assembly includes a pair of adjustably telescopically interengaged hasps with hook configurations on opposite ends adapted to connect with the lockrods in spanning relationship to a door opening and prevent opening of the door. A plurality of openings are formed through the hasps in positions to be in registry with one another when the hasps are appropriately adjusted relative to one another, for receiving a staple and padlock to lock the hasps against relative movement. According to one feature of the invention, the openings in one hasp are spaced differently than the openings in the other hasp, whereby smaller increments of adjustment can be obtained than if the openings were all spaced the same.