Lock Bypass: Opening Without Picking the Cylinder

A bypass occurs when a lock is compromised without affecting the integrity of the lock cylinder.

Padlock shimming is perhaps the most ubiquitous method of bypass.

Common Bypass Methods

Padlock shimming slides thin metal between shackle and body to separate the locking dog. Handcuff shims defeat ratchet pawls. Actuator attacks exploit cylinders whose tailpieces can be manipulated through the keyway gap. Bolt attacks include loiding on spring latches and slim-jim work on automotive linkages.

Magnetic and Electronic Weaknesses

Solenoid-driven bolts and ferrous components may respond to strong magnets placed on the door or frame. Poorly integrated electric strikes sometimes release with a magnet or wire jump — a specification and installation issue, not a pick problem.

Bypass vs. Picking

Picking manipulates internal tumblers; bypass avoids them. A high-security cylinder on a weak strike plate may resist picking yet fail to a latch shim. Holistic security reviews both cylinder grade and installation.

Forensic Notes

Shim marks on padlock bodies, bent latch bolts, and scratched strike plates can indicate bypass attempts. Covert bypass may leave less evidence than drilling.

Defensive Design

Deadlocking latches, anti-shim padlock dogs, concealed actuators, and proper strike reinforcement close common bypass paths. Pair with deadbolts that cannot be carded from the door gap.