How Lock Picking Works -  This is a very interesting article if you have ever wondered about how different locks work and how people stand up and smack them down.

This is a little tricky, as it involves leaving they keyboard to complete the hack. 

Lets take a look at the API in question:

Most deadbolts use a cylinder lock. In the cylinder lock, the key turns a cylinder, or plug, which turns an attached cam. When the plug is turned one way, the cam pulls in on the bolt and the door can open. When the plug turns the other way, the cam releases the bolt and the spring snaps it into place so the door cannot open.

We are also going to need a few tools (not vi or python!):

1. Picks - Picks are long, thin pieces of metal that curve up at the end (like a dentist’s pick). They are used to reach into the lock and push the pins up
2. Tension wrench - Tension wrenches come in all shapes and sizes. Functionally, they aren’t very complex. The simplest sort of tension wrench is a thin flathead screwdriver.

Basic steps:

The first step in picking a lock is to insert the tension wrench into the keyhole and turn it in the same direction that you would turn the key. This turns the plug so that it is slightly offset from the housing around it.

While applying pressure on the plug, you insert a pick into the keyhole and begin lifting the pins. The object is to lift each pin pair up to the level at which the top pin moves completely into the housing, as if pushed by the correct key. When you do this while applying pressure with the tension wrench, you feel or hear a slight click when the pin falls into position. This is the sound of the upper pin falling into place on the ledge in the shaft. The ledge keeps the upper pin wedged in the housing, so it won’t fall back down into the plug.

In this way, you move each pin pair into the correct position until all of the upper pins are pushed completely into the housing and all of the lower pins rest inside the plug. At this point, the plug rotates freely and you can open the lock.

Conceptually, the lock-picking process is quite simple, but it is a very difficult skill to master. Locksmiths have to learn exactly the right pressure to apply and what sounds to listen for. They also must hone their sense of touch to the point where they can feel the slight forces of the moving pins and plug. Additionally, they must learn to visualize all the pieces inside the lock. Successful lock picking depends on complete familiarity with the lock’s design.

 A pin-and-tumbler cylinder lock

You’ll find this sort of lock everywhere, from houses to padlocks. They are so popular because they are relatively inexpensive but offer fair security. For a typical pin-and-tumbler lock with five pins, there are about a million different pin configurations. When you consider the number of lock companies and lock designs, the chances of a criminal having the same key as you is fairly remote.

 A wafer-tumbler cylinder lock

Double-wafer locks have wafer tumblers on both ends of the plug. To pick these locks, you work the wafers on both sides as you apply pressure with the tension wrench. Wafer locks are found in most filing cabinets, lockers and cars, as well as in many padlock designs.

Beyond the paperclip:

Experienced lock-pickers can make do with a few paper clips and a basic screwdriver, but the job is a lot easier when they have the proper tools. A basic lock-picking kit contains a tension wrench and several different picks. The picks differ mainly in the shape of their heads. Different heads are suited for particular sorts of locks and particular picking techniques.

Some lock-pickers will also use an electric pick gun. A pick gun basically consists of one or more vibrating, pick-shaped pieces of metal. You insert these long pieces of metal into the lock, just as you would insert a pick. As the metal pieces vibrate, they push the pins up.

This works something like raking a lock. You turn the gun as the picks vibrate, so you catch some of the pins at the shear line. Sometimes these devices will open the lock in a matter of seconds, and sometimes they won’t work at all. Most recreational lock-pickers avoid these devices because they take the puzzle-solving element out of the process.

Quite an indeph article .  Make sure to check it out for more than the few snippets I showed here. 

This entry was posted on Monday, February 20th, 2006 at 7:36 pm and is filed under Scott, Technology. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.