Bypass

Bypass

A bypass occurs when a lock is compromised without the intended authentication, usually a key or combination. Often, a bypass occurs when the lock's latch or bolt are retracted without the turning of the cylinder, for example by loiding. Bypass takes many forms, and can be either non-destructive or destructive, with non-destructive methods being covert or sometimes surreptitious.

Methods of Bypass

There are few generic methods of bypass for lock cylinders; techniques are specific to design or installation flaws present in certain locks.

Padlock Shimming

Padlock shimming is perhaps the most ubiquitous method of bypass. It involves taking a small piece of metal and separating the locking bolt from the shackle in a padlock. Many low to medium security padlocks are vulnerable to this technique. Shims are available commercially, but can be made quickly with aluminum cans or, surprisingly, sufficiently strong paper.

Lock Actuator Attacks

Flaws in the design and placement of the locking actuator for the cylinder may allow a bypass tool to retract the locking bolt without the proper key inserted, or even internal components being in the proper positions. Various lock manufacturers have suffered from this vulnerability in the past.

Locking Bolt Attacks

Flaws in the design or installation of the locking bolt may allow the bolt to be retracted without using the correct key or picking the lock cylinder. The classic credit-card opening of doors and slim jim on cars are two popular examples.