I show how pin-tumbler locks work and how they can be opened using lock picks. This is a fairly basic view about lock picking but I wanted to make it comprehensive to give people a good idea of the concepts. As well as a foundation for beginners in lock picking to get a better view of how a lock works and how it can be exploited. The pin-tumbler is a very common lock mechanism that uses pins of varying lengths to prevent the lock from opening without the correct key. Most locks around the home or office are simple pin-and-tumbler locks and can be relatively easy to open using a pick and a tension wrench.

While the process is simple and can be mastered with practice, picking such a lock requires a great deal of patience. It can be a hobby as well as a practical skill. Locksmiths define lock-picking as the manipulation of a lock's components to open a lock without a key. To understand lock picking you first have to know how locks and keys work. Most locks are based on fairly similar concepts but they do come in all shapes and sizes, with many design variations. As this is just to cover the basics I don’t go over security pins or more advanced techniques. This is for educational purposes only.

Lock picking is the art of unlocking a lock by analyzing and manipulating the components of the lock device without the original key. In addition, ideal lock picking should not damage the lock itself, allowing it to be re-keyed for later use, which is especially important with antique locks that would be impossible to replace if destructive entry methods were used. Although lock picking can be associated with criminal intent, it is an essential skill for a locksmith, and is often pursued by law abiding citizens as a useful skill to learn or simply a hobby. The move towards combination locks for high security items such as safes was intended to remove the weakest part of the lock: its keyhole.

Step 1: How a Lock Works:

A pin-tumbler is a cylinder based lock design that uses movable pins to prevent rotation of the plug. A key is used to properly elevate pins to allow the plug to rotate and the locking bolt to be retracted. Pin tumblers are a series of pin stacks pushed down by a spring. Each stack must be properly raised to allow pins to separate at the shear-line. Once all pin stacks are separated the plug can freely rotate and actuate the locking bolt to lock or unlock the lock. An incorrect key will not align all components correctly; rotation of the plug will be blocked at the shear-line.

- Key pins (bottom pins): The pins that are touched by the
key. Key pins are sized differently corresponding to the different depth cuts on the key. When the correct key is inserted, all key pins are aligned at the shear line, allowing the plug to rotate.

- Driver pins (top pins): The pins placed between the key pins and the springs. In their resting position, the driver pins block rotation of the plug. In more advanced pin-tumblers, driver pins may be sized inverse to the key pins to defend against decoding and attacks via comb picks.

- Springs: Springs placed above the pin stacks push pins down to their resting position, ensuring that pins cannot be trapped above the shear line while the plug is in the default position.

- Plug: The plug is the inner piece of the lock that rotates upon insertion and tension of the correct key. The plug is connected to the cam to actuate the bolt mechanism when rotated.

- Cylinder: The cylinder is the outer piece of the lock that houses the upper pin chambers and the plug. Driver pins and springs are trapped in the cylinder's pin chambers when the correct key is used and plug rotated.

- Cam: The cam is an extension connected to the back of the plug which actuates the bolt mechanism to lock or unlock the lock.

The diagrams and information on pin-tumbler locks: https://en.wikipedia.org/wiki/Pin_tumbler_lock

http://www.lockwiki.com/index.php/Pin_tumbler