Abstract: A portable security lock for an inwardly opening door. Matching short and long locking blocks are held together by screws or other suitable fasteners. A locking bar having an insertion section that can be placed in the strike plate of the door jam is provided. The locking bar further has a row of teeth that face the insertion section. A pivoting arm, connected to the attached matching short and long locking blocks is provided. The pivoting arm has a locked and unlocked position and a series of teeth that mesh the teeth of the locking bar. When the locking arm is fully engaged against the locking bar via the respective sets of teeth, the locking bar is held firmly in position.