Lock picking

A traditional set of lock picks. The two tools on the left are tension wrenches

Lock picking is the art of unlocking a lock by analysing and manipulating the components of the lock device, without the original key. Although lock picking can be associated with criminal intent, it is an essential skill for a locksmith. Lock picking is the ideal way of opening a lock without the correct key, while not damaging the lock, allowing it to be rekeyed for later use, which is especially important with antique locks that would be impossible to replace if destructive entry methods are used.

Usually it is possible to bypass a lock without picking it. Most common locks can be quickly and easily opened using a drill, bolt cutters, bump key, or a hydraulic jack. The hasp, door, or fixture they are attached to can be cut, broken, or otherwise removed.

A lock that offers high resistance to picking does not necessarily make unauthorized access more difficult, but it will make surreptitious unauthorized access more difficult. They are often used in combination with alarms to provide layered security.

Some people enjoy picking locks recreationally, because they find it brings high satisfaction and is an enjoyable way to pass the time; it also has hack value.

Techniques to pick different types of locks

A tension wrench (or turning tool, as it is more accurately described) is used to apply a torque to the cylinder plug, while a lock pick is used to push individual pins up until they are flush with the shear line. As each pin is manipulated to its correct height, the cylinder will turn fractionally causing another pin to bind. The pins will not bind simultaneously because they will not be aligned perfectly with the axis of the cylinder. Once all of the pins are flush with the shear line, the tension wrench can be turned fully to open the lock.

Raking a pin tumbler lock is usually done before individual pins are pushed up. While applying torque with the tension wrench, a lock pick with a wide tip is placed at the back of the lock and quickly slid outwards with upward pressure so all the pins are pushed up. Raking may allow some of the pins to be flush with the shear line and can make the job easier.

Most simple pin tumbler automatic padlocks can be picked without a torque wrench using the so-called safety-pin-method. These padlocks allow the picker to open the lock while applying pressure to the side and raking at the same time - with the same tool (a bent wire in this case). Because the cylinder has to be turned only 1/8th of a full turn, and there are only 3 or sometimes just 2 pins to set, the lock simply jumps out of its place. Cheap and small padlocks may even open more easily with a safety pin than with a key.

Some pin tumbler locks have special security pins, with serrations, mushroom heads, or spool shapes, that make lock picking slightly more difficult by causing the top pins (oft-referred to as "drivers") to bind in locations other than their correct ones.

Another technique, often the fastest, uses a "pick gun" (either manual or electric), which sharply strikes all the bottom pins simultaneously while light torque is applied; like a cue ball, the energy is transmitted through to the top pins, which fly to the top of their respective pin chambers. This momentarily creates a gap between the top and bottom pins, and the plug of the lock can then be turned if all of the bottom pins remain below or at the shear line while all of the top pins remain above or at the shear line.

Another application of this technique is the use of bump keys. These are keys with all the cuts at or slightly below the deepest level for a key made by the manufacturer, and a small amount of material removed at the tip, and, where applicable, at the shoulder - the part of the key that prevents the key from entering the lock too deeply. By sharply striking the bump key, it is possible to apply an even impact to each pin column, which then separates as if struck using a pick gun. Bump keys will work in many locks that pick gun needles will not fit into.

To defend against these attacks, many high-security locks use a sidebar, which engages from another axis and also prevents the lock from turning. Medeco locks do this by requiring the pins to be rotated to a correct position, as well as moved to their correct height. Other brands such as ASSA put the sidebar cuts in the side of the key. By design, a common trait among high-security lock cylinders is the usage of more than one shear line.

Pin tumbler locks

Function

Pin tumbler locks work in the following fashion. There exists a cylinder which has a key hole in it. This cylinder fits into a housing. The cylinder is the part of the lock into which one normally puts the key (typically Kwikset or Schlage). The cylinder has vertical holes (typically 5–7) drilled into it. These holes are perpendicular with the keyhole. These holes correspond (although not perfectly) to holes in the housing which the cylinder sits. Within each of these vertical holes are pin stacks.

There are two pins (one on top of the other) to a pin stack (assuming a non-masterkeyed system) and a spring. If one were to remove the cylinder from the housing and put the proper key into the cylinder, due to the varying cuts of the key, the key would lift these bottom pins such that they are flush with the cylinder. If there is no key in the cylinder, the springs on top of each pinstack press the top pins (driver pins) downward into the cylinder and thus preventing the cylinder from turning unless the proper key is inserted.

Picking — manual

Two elements are needed to pick this type of lock. Torque applied to the plug, and a pick to lift or rake/scrub the bottom pins. There are also snap guns which easily accomplish the following feat. Essentially, one inserts a tension wrench into the cylinder to apply a light amount of torque on the cylinder. One then uses the pick to feel around to find what pins can be lifted. One is able to lift a pin because the vertical holes are never exactly in a line, so there is more pressure from the cylinder torque on some pins than on others.

After a pin is lifted, the torque placed on the cylinder plug will force the pin to lock in place. This process is repeated until all pins are set, then the cylinder turns and the lock is successfully manipulated.

Finding the right picking force

First, one feels inside the lock with the pick (without worrying about the tension tool for a moment), checking each pin in turn. The pins will feel springy (as they are on springs), and one should be able to count the pins, noting how much force is needed to move them (generally much less than most people imagine). The most common error at every stage is using too much force—the force used to push the pins with no tension tool inserted is almost the force needed when picking.

Finding the right tension-tool force

When a small turning force is applied to the lock in the direction that the key is normally turned, the tumbler will rotate a bit. The smallest force that takes up the slack in the lock is almost the force needed to pick the lock, at least until the pins are set. More force might be needed to open the lock once the pins are set. Again the most common mistake is too much pressure. If you can't seem to get it, try less pressure. You'll be surprised how little pressure is needed once you "pop" your first lock.

Picking - automated

Operating on the same principle as that of a cue ball suddenly hitting the 8-ball and coming to a stop, while sending the 8-ball flying, the snap gun strikes all of the bottom pins at once, and thus sending the driver pins up into the lock. This only lasts for a fraction of a second because the springs will force the pins back down into the lock. The tension wrench is also required in this situation.

Newton's cradle is often used to explain the mechanism, but really we need to consider a modified Newton's cradle with unequal masses. When the masses in Newton's cradle are not all equal, the situation is more complex, but to avoid considering the physics in detail, we consider two simple examples. Real locks do not in general have all equal masses!

Example 1. Consider three masses 2m, m, and 2m, in that order, and suppose that the first mass is moving at velocity v and the other two are touching and at rest. After the first mass hits the two touching masses, the first and second masses are at rest and the third mass is moving at velocity v. So, in this case, it is almost like Newton's cradle with all equal masses.

Example 2. We use the same three masses as in Example 1, but in a different order. Consider three masses of 2m, 2m, and m, in that order, and suppose that the first mass is moving at velocity v and the other two are touching and at rest. After the first mass hits the two touching masses, the first mass is at rest, the second mass is moving at velocity v/3 and the third mass is moving at velocity 4v/3. Notice here that both the second and third masses are moving in the same direction, and think about the effect this might have in a lock being picked as described above.

However, even when the masses are not equal, we do in general create gaps between the masses that were originally touching, so the hope is that we can arrange it so that this gap contains the shear line for all the pin stacks at the same time. If so, the lock is picked!

Bumping and Kicking

Another method for defeating this type of lock is known as bumping. In this method, a key blank that fits the target lock is specially cut, with all the cuts at or slightly below the deepest level for a key made by the manufacturer, and a small amount of material removed at the tip, and, where applicable, at the shoulder - the part of the key that prevents the key from entering the lock too deeply. This allows the key to be inserted slightly farther into the lock than normal. The key is inserted into the target lock to normal depth, and by striking the head of the key while applying slight torsion, the lock can be opened in seconds.[1] This method emulates the snap gun approach with decidedly simpler tools — the special key and a device (e.g., mallet, screwdriver handle) to deliver the blow. When used with criminal intent, bumping often does not allow the victim to make a successful insurance claim because it leaves no sign of forced entry.

Bump keys, like electric pick guns and snap picks exploit impulsive impacts on the pin stack, as described above, to open the lock quickly and effectively.

Lever locks

Lever locks can be picked by putting a force on the bolt in the direction that withdraws it, then moving the levers up (and down again if necessary), generally one-by-one until the stump on the bolt passes through the holes in the levers.

Many lever locks use anti-picking notches on the stump and levers, for example British-standard (BS) lever locks. These are the equivalent of security pins in a pin tumbler lock, and cause the picker to incorrectly believe that a lever is at the correct height.

Chubb's detector lock, which is no longer in general manufacture, could mechanically detect a lever being lifted too high, and would then refuse to open until the mechanism was released by using the correct key (sometimes called a regulator key) in the lock. This method is very difficult.

Tubular pin tumbler locks

A tubular pin tumbler lock has the pins arranged in a circular pattern (parallel to the keyhole), and uses a tube shaped key. Tubular locks are commonly seen on vending machines, computers and some bike locks.

A tubular lock pick is used to keep the pins from moving once they have been picked until all have been picked. These locks can be picked using a pin and a torsion tool, but using this method is far slower than using a tubular lock pick, and for many locks the process has to be repeated several times as the cylinder is rotated to open the lock.

It is possible to open many tubular pin tumbler locks by inserting a ring of soft material, cardboard, or even the tube from a ballpoint pen into them, and wiggling it while applying a constant gentle rotative force. The soft material deforms, allowing each pin to work its way into the picking tool until the pin is in the correct position, whereupon the pin no longer deforms the cardboard, or plastic etc. When all pins are correctly set, the lock opens. This is a form of impressioning.

Wafer tumbler locks

To open a wafer tumbler lock, one can use a double-sided pick to keep the wafers from moving once they have been picked until all have been picked. Although double-sided picks may work well with wafer locks, many times using a hook pick rightside up, then upside down works equally well.

Combination locks

Various methods can be used to open combination locks, none of which are technically picking. These methods are instead called bypassing.

Cheap combination padlocks can be opened using a thin metal piece slid between the body and shackle; the padlock shim technique can also work with non-combination padlocks.

Other combination locks require the opener to find the combination to the lock. The exact techniques differ and some manufacturers, such as Master Lock, make this process very time-consuming on their latest models.

All combination locks carry the inherent flaw that a finite number of random attempts will eventually open the lock. This process can be dramatically shortened by using techniques that the lock-maker has built into the lock, such as patterns in the combinations often using factorial and modulus. See hacking a Master Lock.

Warded locks

With a warded pick, warded locks are probably one of the easiest locks to pick. Warded picks have basic shapes that fit many types of warded locks. They are inserted into the keyhole and slowly turned until the lock opens.

Key impressioning

Concept

Contrary to what one might think upon hearing the term, key impressioning does not have anything to do with molds. Instead, one starts with a key blank.

Method

Tools required

Proper key blank that will fit the lock

Vise-grip pliers

Rat tail and pippin files (Swiss cut #4 variety)

Skilled eyes

Clipping the vice grips on the key blank, one uses the file to polish the top of the key; that is, the part of the key that the pins come into contact with. (Before starting the impressioning, it is good to count the number of pins in the lock with a hook pick, thus helping choose the correct sized blank.) The key is put into the keyhole using the vicegrips and gently turned, binding the key, which is then jiggled up and down. Upon withdrawing the key blank, one will find perpendicular scrapes that the pins of the lock will have left on the key. Filing a few thousandths of brass off of the key with the pippen or rat tail file (about four swipes of the file).

The process is repeated, being careful to only file if a little dimple is seen in the key grooves. When enough material has been filed from the blank, the blank will approximate cut of the key and the lock should open when the key is turned.

This method is exceptionally good because high-security drivers (if they are grooved or mushroomed) are made irrelevant. This method works well on car doors and other wafer locks. To impression wafer locks, one should sharpen both sides of the key (only if the key is two sided) then the wafers will slice a nice little groove into the key.

This process could take 15–75 minutes based on the skill of the locksmith and the difficulty of the lock. This method is more time consuming and difficult on locks with sidebars (i.e., Medeco, GM cars)

Type of tool

The following is a list of tools that would be found in a commercial set. Depending on the size of the set it may contain sizes and/or designs to better fit different locks. Most all of them are made of thin steel or other hard metals.

Fabricating Your Own Tools

If you are planning on fabricating your own lock picks I suggest using the long pieces of metal found on windshield wiper blade replacements. You can cut them to whatever length you want (I prefer longer... up to 9" but it makes it a bit harder to carry around). It should fit in most key locks at this point but you will need to file/grind it down in thickness so it doesn't get stuck in the lock. A bench grinder works well for this. A metal hand file (found in any hardware store) is good for final touches on your picks and tension wrenchs. Finally, once everything is to the desired shaped and thickness, I suggest tempering the metal by heating it up until it is glowing red hot, and then putting it into cold water. Repeat this several times to strengthen the metal. You want your picks and wrenches to keep their desired shape.

Tension wrench

The Tension wrench, or torsion wrench as it is more accurately described, is used to apply torque to the lock plug to keep pins from being pushed back down by springs after they are correctly set at the shear line. It is usually anywhere from 1/16th inch to 1/8th inch wide, bent into an L, and occasionally has a quarter twist on the long side.

Hook pick

The hook pick is self explanatory, it is similar to the half diamond pick, but has a hook shaped tip rather than a half diamond shape.

Legal status

United States

In United States, laws concerning possession of lock picks vary from state to state. Generally, possession and use of lock picks is considered equivalent to the possession of a crowbar or other tool that may or may not be used in a burglary. Illegal possession of lock picks is generally prosecuted as a felony under the category of possession of burglary tools or similar statutes. In many states, simple possession is completely legal as their statutes require proof of intent. In some states, however, possession without appropriate licensure is considered prima facie evidence of intent to commit a crime (in California for example), rendering simple possession a crime.

California

In California, locksmiths must be licensed by the state. However simple possession is completely legal as illegal possession must be coupled with felonious or malicious intent.

European Union

Most countries of the European Union don't regulate the possession of lock picks. All responsibility concerning criminal or legal acts using the picks is taken by the user of the lock picks, when the owner of the lock picks may be involved in the jurisdiction or legal process as an accomplice or witness.

Netherlands

In the Netherlands, owning lock picks is legal, but using them on someone else's locks without permission is not. There is a lock picking championship, the Dutch Open (organised by TOOOL), which was reported on in the newspapers.

United Kingdom

In the United Kingdom, a person who carries a lock pick set (even a home made one) can be charged with the offence of "going equipped", unless they have a good reason for carrying them. The penalty for this can be upward of 5 years' imprisonment. The arresting officer must have "reasonable cause".

New Zealand

In New Zealand, possession of lock picking tools "without lawful authority or excuse" falls under the crime of "being in possession of instrument for burglary", which carries a maximum penalty of three years' prison, if accompanied by the intent to use it for burglary.

See also

• Hotwiring
• Lock bumping
• Safe-cracking

External links

• Map detailing locksmith legislation in different states in the U.S. - Courtesy of ALOA.