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COMPROMISING LOCKS
Time to
share what little knowledge I possess about lock picking. I have
tried to include as much information about the different types of locks
that I am familiar with and the techniques that may be used to compromise
them. This list is not exhaustive by any means. It simply covers the types
of locks that I have been exposed to and have had the time to research.
There is a section concerning the implications of relying
on locks for your personal security purposes at the end of this document.
I do not hold a degree in this subject: remember I
said "little knowledge". If there is information in this document that
you believe to be erroneous, please feel free to contact me and I will be happy
to change or remove the material in question. Enjoy.
LEGAL
I guess I should indulge myself in a little preach about the implications
of this knowledge. I do not in any way condone the criminal negligence
that may occur from the misuse of this information. I am not teaching the
reader how to become a criminal. This information is presented strictly
for educational purposes. If you -DO- misuse this information you -WILL-
be committing a felony. Knowing how to pick a lock is no more criminal
than knowing how to use bolt cutters or how to project a brick through a window.
ANATOMY: PIN TUMBLER PADLOCKS
What better way to become familiar with a lock than to look inside one. The following
pictures pretty well surmise the inner workings of a standard pin tumbler
pad lock. To disassemble a lock you must first cut the thru-bolts. When
this is achieved and the bottom plate is removed the lock will look something
like what we see in figure 1.
From this view we can clearly begin to see the internal mechanisms of the lock. Let's
remove them and take a closer look..
The most important component of a lock is the center item in figure 2. The locking mechanism.
What exactly comprises this mechanism you ask? Move on to figure 3.
Looking more closely at figure (3)..
The main cylinder (1) terminates into an interface at the top of the lock
and when rotated depresses a lever that opens the lock. The holes
that are bored through the top of it accepts the key pins (4). These pins
are random in size and dictate the "key" of the lock. This cylinder resides
within the cylinder body (5) which holds the set pins (3) which are spring
loaded into their appropriate columns. These items are assembled together
and locked into place with the spring clip (6).
When a key is inserted into a lock (figure 4):
it moves the key pins to their necessary
height which also raises the set pins. When the set pins clear the
shear line they enable the main cylinder to rotate freely thus opening
the lock.
ANATOMY: PIN TUMBLER DEADBOLTS
Dead bolts are very similar to padlocks, not only in concept but also operation. The
pictures below ( figure 5 & 6 ) are that of a cylinder from a
standard dead bolt. These come in various sizes and pin variations and
may also be comprised of different materials depending on manufacturer.
I included Figure 5 so that you could see how the pins are arranged while
at rest. Notice how the key pins stop at what is the middle of the radius
of the cylinder just above a key ward. This is what keeps these pins in
place.
There are some noticeable differences between padlock cylinders and dead bolt
cylinders. The first thing that you will likely notice is the number of
pins. Dead bolts usually contain anywhere from 5-8 pins while padlocks
are limited to 4-5 pins. These pins are also slightly larger in size
than those of a padlock.
The more expensive the dead bolt or padlock, the more intricate the pin design and
implementation. Although there are many different implementations
of parts and assembly, all locks of these types follow this basic design.
I will spend a little more time on the subtle differences between manufacturer
designs a little later on as these differences pertain to picking them.
I would like to cover one more lock design before I jump into some theory.
ANATOMY: WAFER TUMBLER MECHANISMS
These locks can be found just about anywhere, from jewelery display cases
to the furniture cabinets that are in your living room or washroom. See
figure 7 for an example.
Wafer tumbler locks typically implement some type of lever catch system. The
catch usually consisting of a metal stop plate or a mortised hole that
accepts the lever in whatever material the lock happens to be installed
in.
A quick glance at that key tells us that there is at least 6 pins in this devil.
Sound threatening? Don't let these locks fool you. They are technologically
inferior to their pin tumbler counterparts. In fact, they don't contain
any pins at all.
These locks rely on a series of spring loaded brass wafers
for their security, see figure 9.
To determine whether it is a pin tumbler or wafer tumbler mechanism that you are up
against the following tests should quickly confirm the type:
Visual inspection:
1) Look into the key-way and examine the first pin/wafer. If they are visible it
is usually a dead giveaway.
2) Cylinder displacement. The key cylinder is usually ill fitted. You will notice significant side
to side play as force is applied to the cylinder.
3) Pin resets. Due to the construction of wafer locks there is a lot of dead space surrounding the
parts. If you depress the wafers and quickly release them you will notice that they make a "snapping" sound as opposed to a "click" as expected of
pin tumbler models.
That said, let's take a closer look at the semantics of wafer designs.
Looking at the cylinder body (item on the right in figure 8) we can see
that their is more than one position that the main cylinder can lock into
place. The reason for this is that the key cylinder is not controlling
a complex opening mechanism (interacting with other levers, springs, etc).
The state of this lever is either 1/4 turn to the right "open"
or 1/4 turn to the left "closed". This of course depends on orientation.
So what are the other two flutes for? Let's look what happens when the
key is inserted..
As the key passes through the wafers it moves them up and down (figure 10). The
wafers that are up reside in the upper flute of the cylinder body
and the ones that are pushed down reside in the bottom flute. Until the
proper key has been fully inserted their will always be 6 points of contact
on the main body. This ensures that the lock will provide maximum security
if anything not resembling the original key were to be inserted and turned.
Wafer
tumbler locks while anatomically different from pin tumbler mechanisms
still react to the same pin manipulation techniques.
Now that we have covered the basics of simple design, let's move onto some theory on how it is possible
to open these types of locks without the use of keys.
THEORY: PIN/WAFER TUMBLER MECHANISMS
So why are we able to pick locks?
Let me explain. Look closely at the following image for a moment:
The picture above ( figure 12 ) is that of a dead bolt ( same one from figures 5 &
6 before I chopped it in half ). I have placed two set pins, one at each
end to stabilize the key cylinder. The key is under pressure, gravity to
be more precise. Now, carefully examine those columns. Do you notice anything
odd as you peer down them?
If you look closely you can see that the top
of the key cylinder is visible (brass ledge). Why?
Locks are not exactly a precision instrument. In order for
a lock to operate smoothly there must be some play in the system.
This play is achieved by the allowance for these columns to be slightly
larger than the pins themselves. If they weren't, the first piece
of dirt, grit, etc. that entered these columns or the expansion and contraction
of the malleable metals that comprise these parts, would hinder it's operation.
Also, as the lock ages (repeated usage's) friction may play a role
in further expansion of these columns.
Going back to figure 12 for a sec. If I got out my micrometer and measured each
overlap I would notice that the distances away from the cylinder body would
not be consistent.
What I mean by this is:
If I drew a straight line
across these columns, the point at which the cylinder holes make contact
with the line would not be exactly parallel. This is due to the inherent
play between the cylinder and the cylinder body. In order for the cylinder
to spin there must be an allowance for movement. When a key ( or something
simulating a key ) is inserted and turned there will be side pressure on
the cylinder causing it to skew and create this situation.
This "play" I mentioned varies from lock to lock. The more expensive the
lock, the more likely it was designed with superior materials and more
advanced machining processes. With this, tolerance levels will be decreased
and the lock will be more difficult to pick. There are also other methods
that manufacturers employ that can make picking a lock not only more difficult
but also frustrating.
Above (figure 13) is a picture of a key pin and a set pin. These are actually
butted up tight to each other. Notice how where they make contact they
are rounded and not flat.
Considering what we have examined so far, we can deduce that as long as there is pressure
on the key, the cylinder holes will overlap the cylinder body creating
a ledge. Even if the pins were flat, they would most likely get stuck on
this ledge and the fact that they are tapered (more surface area for contact)
just reinforces there tendency to get stuck. Now, considering the inconsistency
of this ledge, every time a pin is lodged past the shear line ( see figure
4.) the cylinder will move slightly. If the pressure on the cylinder is
maintained and another pin is depressed it too will get caught on this
ledge, and so on.
So if we can insert something into the key way and apply pressure (a torque wrench)
and use another utensil (a pick) to push on those pins until they become
trapped, the cylinder will be free and the lock will open :).
TOOLS: PIN/WAFER TUMBLER MECHANISMS
Although some locks can be picked with a couple of paper clips, if you
wish to tackle more difficult locking mechanisms you will require a set of lock picks. A modest set of picks will set you back around $30 and
can be easily found online. Later I will explain some methods of devising
your own instruments for picking locks. A basic set includes the following items.
Hook pick:
This is a great all around pick. It is most useful for pin-at-a-time
picking. It can also be used for scrubbing. The main advantage of this
pick for scrubbing is that you can usually reach over the second last pin
if it is set high while the last pin is set low. It also provides you with
a little more control on individual pins.
Diamond pick:
As you become a little better at lock picking this is the pick
of choice for scrubbing. They are available in many different sizes but
you will probably find the smaller more tapered edge type is the most versatile.
The brass handle that you see is typical. The pick is held in place with
a couple of hex head set screws. These can be loosened so that the
handle may except other picks.
Snake pick:
Again, designed specifically for scrubbing. The main advantage
of this pick is the likelihood of the pick setting more than one pin at
once. On an easy lock you can sometimes open it with one sweep.
Torque wrench:
The torque wrench is simply used to apply pressure on the cylinder. They come
in various sizes and it is a good idea to have some smaller ones (in width)
on hand. When working on some of the more advanced locks a feather torque
wrench (relies on springs) can really come in handy.
There are many other types of picks available on the market. However with
this basic set and some skill you should be able to pick most of the pin
tumbler locks you will encounter.
Note:
There are some lock designs that can not be compromised with conventional
lock picks, such as tubular locks and warded pad locks. There are picks
designed specifically for these types.
BEGINNINGS: BASIC TECHNIQUES
Before I go any further I would like to take a minute to say a couple of
words to the beginners / skeptics out there. Lock picking is
NOT
achieved because of the tools. You don't just pick up a set of lock picks
and stupefy your friends by being able to open all sorts of things.
To
be a master at lock picking you must be a master of your senses. It is
a skill that takes practice and diligence. Think of the picks as
a physical extension of your mind. They are merely present to assist you
in identifying certain qualities within a lock. Once identified and interpreted
correctly, these qualities may be used to circumvent the mechanisms of
the lock.
The first thing you should do If you are interested in becoming proficient at lock
picking is to find some locks that you can play with. Any lock will do
really but I do not recommend beginning with brands like Medeco(tm)
and Schlage(tm) (explained later) and preferably not the dead bolt on your
neighbors front door. Unless of course they are away on vacation and you
need to feed their cat.
You may have some locks laying around your house. If not, go to the hardware store
and buy the cheapest padlock you can find. Try and find one that
is a decent size so that it will be more comfortable in your hand while
you are still a little "wet behind the ears" lock picker.
I have chosen to begin with padlocks strictly because they are a little easier
to practice on while you build up your dexterity with the tools.
Lock picks; although tools are not the same as say a hammer or screwdriver. They are
precision tools comprised of very soft materials. Consider this as you
are practicing. If you are bending your tools, then you are definitely
doing something wrong. Force is not your ally.
To begin place the lock in your hand. The easiest and most comfortable way
of holding a padlock is with your middle finger through the bolt with the
pins facing your body. Insert the torque wrench applying only enough pressure
to keep the wrench inserted in the key way.
Next insert your pick. For this exercise we will use the hook shaped pick. We will
begin by trying to set each pin individually. Although this process is
usually reserved for more difficult locks it clearly demonstrates
how to recognize setting pins.
How much torque?
Typically, to open a lock you require only enough torque to spin the cylinder,
which once freed from the pins will be very little. The torque required to trap
the pins in their respective columns varies, and is influenced mainly
by environmental conditions and the quality of the lock.
The biggest mistake
beginners make is applying far too much torque thus bottoming out the pins
or jamming them altogether. Be gentle and reap the rewards. The easiest
way to judge the proper torque for your lock is to insert your pick, beginning
with the diamond or hook, and gently sweep the pins from back to front waiting
for a pin to set. The lowest amount of torque that it took to set that
pin is usually the amount of torque required to pick the lock.
While applying torque on the cylinder gently push down on the first pin.
When a pin sets it will make an audible "click" which will also be transferred
to the pick itself and felt. If nothing happens maintain your torque and
depress another pin. When you reach a pin that sets search for another.
If you have depressed all of the pins yet none will set increase
your torque and start over.

While you were performing the above you probably noticed that as pins began to
set that the cylinder also slightly rotated. This is a very important feature
that locks display as the shear line is cleared of the pins. There are
times when you are picking that you are unaware of pins setting, this feature
helps to assist you in determining the progress of picking at hand.
There is no _real_ order as to how the pins will set or how much the cylinder
will turn as pins are set. It all depends on the the type of lock and the
manufacturer. If at some point you feel as though all of the pins are set
yet the lock will not open, you have probably lodged a pin too far past
the shear line so you must begin again.
If you get frustrated, take
a break.
How many pins?
It all depends. To check insert your torque wrench, pick etc. until it hits the
back wall of the lock. Depress it onto the pins and slowly drag it out
of the lock. Listen carefully as the pins pop back into place counting
as you go. Most padlocks have 4 pins, some have 5 (typically brass). Dead
bolts have anywhere from 5 to 8. It all depends on the manufacturer. So
check before you pick.
While on this subject I would just like to mention
that the amount of pins rarely has anything to do with the security of
a lock.
Which way to turn?
On our test subject it doesn't matter as we can see ( figure 16 ). The cylinder
when in place can pull the lever either left or right. Not all locks are
the same, especially when it comes to dead bolts.
Before you do anything
with a lock you must determine which way to turn the cylinder.
To determine the turn of a lock insert your torque wrench in the cylinder and apply
moderate pressure both ways. The direction that offers the least
resistance i.e.. not an instant _dead_ stop, should be the turn of the lock.
Another simple test that you can employ is to insert your torque wrench
and apply ample force on the cylinder both ways. As you do, brush
your pick across the pins and note whether or not they begin to set. On most locks all
of the pins should set only on the correct turn.
Once you do succeed in picking your first lock, begin timing yourself on that lock.
When you can pick a familiar lock, pin-at-a-time, in less than 10
seconds it's time to move on.
What about dead bolts?
Most people find it a little awkward at first working on dead bolts.This
is usually due to the fact that they are accompanied by a large door and
fastened to it quite well. You cannot manipulate the lock to improve your
positioning so you must rely on your dexterity with your tools 100%.
The techniques that you used on the padlock are exactly the same as you will apply
to dead bolts. You will however require a little more skill in identifying
set pins as dead bolts tend not to give as easy as padlocks.
Note: I just noticed that from what I have said so far I am creating the impression that dead bolts
are much more difficult than padlocks. This is not necessarily true.
There are some very decent padlocks out there that are very difficult to
pick.The likelihood of encountering one however is rare.I
will maintain my current distinctions between the two for the rest of this
paper but keep in mind for the sake of accuracy, that it all depends
on the make of the lock.
MOVING ON: OTHER TECHNIQUES
When you
are comfortable with pin-at-a-time picking you should learn these two other
common methods for pin manipulation.
Scrubbing
Insert you pick and torque wrench into the key way and begin raking the the pins
gently
back and forth. The idea here is to gradually yet synchronously increase
the force applied by both the pick and the torque wrench until the lock
opens.
I cannot stress enough that you MUST be gentle with both your pick and your wrench
during this exercise. To be successful you must let the lock do all of
the work. All you are trying to do is kindly coerce it into doing what
it was designed to do. Feel what is happening inside, listen. The lock
will tell you exactly what is happening as long as listen and feel.
<-
starting to sound like an excerpt from the Karate Kid.
After a few sweeps if the lock has failed to open try gently pushing on each pin individually.
If the lock is a little stiff or you are over torquing the lock a pin may
require a little extra push to clear the shear line. Be gentle, ease off
your torque, try again.
Bouncing
Slowly insert your pick into the key way, gently rocking it up and down
as you go. You should have minimal torque on the cylinder while performing
this exercise.
Basically what you are trying to do is achieve as much contact
at different levels with the pins as your pick passes over them. Maintaining
consistent torque on the cylinder is vital for this process to work. If
executed correctly the lock should open up pretty quick.
The techniques mentioned so far are typically combined to rapidly
open a lock. Only the person operating the pick will know which is best
and at what time to employ them.
The most difficult thing about lock picking is just this. Choosing your plan of
attack. You must approach each new lock as a challenge and never allow
yourself to become a victim of the memory effect.
Beginners especially,
may be inclined to become accustomed to a particular lock. Now, they can
pick this lock in about 2 seconds, knowing exactly the order and just how
much tension and pressure it will take for the pins to pop. So, with this
lock they have acquired something; the sequence of operations for brand
"X", a template if you will.
From this point on, this template will be
used for all locks to follow.
As you can guess from what we have learned so far, this will not get them very
far. With each new lock, there is a new challenge.
When you first insert
your pick into a lock, never begin with the assumption that it is going
to open. Assume that you are going to learn something from it, nothing
more. And if it happens to open, then great. If not try to gather a little
more information about it and try again.
TRICKERY: SMOKE AND MIRRORS
Time to talk about some of the things that designers do, sometimes inadvertently, that
make some locks more difficult and others easier to pick.
1) The most frustrating item has to do with key wards. Key wards are the guides that stabilize the
key as it enters the cylinder. On some locks the wards are very close to
the pins obstructing the use of a conventional pick.
Sometimes there is
no way around this. Other times the use of a filed down hook pick usually
solves the problem. You must remember that even a paper clip can open a
lock. Use whatever you can find that will fit. Improvise!
2) Sometimes while picking
a lock you will find that the order that the pins set isn't really to your
advantage. If the second last pin sets high while the last pin must be
set real low, and this is the order, then we have a problem.
It is sometimes impossible to get over that second last pin, and depending
on clearance you may have to abandon the lock altogether. There is one
way of approaching this. If you take a piece of #4 or #6 wire ( or a paper
clip ) and put a slight curve in the end you may be able to sneak past
that pin. When you hit the back wall of the lock apply a enough pressure
to continue bend so that you may reach that last pin.
This is really hard to pull off but can work.
3) The lock pictured below happens to contain two sets of pins. The second
set are usually referred to as master pins. These pins are present so that
the lock can be opened by two completely different keys.

Note the additional pin between your typical key and set pins. As mentioned
earlier as pins are cleared of the shear line the cylinder will slightly
rotate. With the addition of these pins you have created a number of different
shear lines. This will greatly increase your chances of picking this type
of lock.
4)The dreaded Medeco(tm). Medeco is a high security lock manufacturer. They're
products are expensive and secure. Their locks are common
within commercial businesses, restaurants etc. These are by far the hardest
locks to pick.
Primarily these locks owe their security to precision
machining practices, and the clever sidebar they utilize (figure 18). These
locks are very tight and smooth with little play. The pins are beveled
in all kinds of shapes to impede picking (discussed below). These bevels
play a further roll in allowing the key pins to align correctly with the
sidebar when the proper key is inserted. Below is the cylinder from a Medeco
padlock.
If we remove this bar the Medeco cylinder responds to picking as can be expected
from any other cylinder. The test to the reader here is to be able too
identify just when this bar is free.
Taking a look at the columns in figure
20 you will notice that their is a cutout (about 20%) into the plug which
restricts the key pins to rotate within this constraint. This is not very
encouraging as it severely decreases the odds of proper alignment by a foreign
object. Furthermore The alignment is not static (figure 22), it varies
from lock to lock which unfortunately blows away the idea of creating an
alignment jig.
Theoretically speaking, it may be possible to concentrate your efforts on freeing this
sidebar while not over torquing the plug to a point where pin setting would
be impossible. Using your diamond pick with very little torque on the plug
employ a side to side in out sweep over the pins. You are not trying
to set pins here, as this would impede the rotation of the key pins, you
are merely trying to align them with the sidebar.
If you can correctly
align these pins there will be a slight give in the plug, a very slight
give. At this point you have not entirely freed the bar from its notch,
which is good because if it travels too far you would cause pins to bottom
out on the cylinder body. You have merely depressed it enough to
transfer force back on these pins to keep them in line with the side bar.
Please note that this is _very_
difficult, but if you get to this
point it will be possible to set the pins and open the lock. It may be
worth to mention that you must be very careful while scrubbing the pins
after they have been aligned. In fact you should probably concentrate on
one pin at a time.
The scenario that you created by aligning the key pins
with the sidebar is very delicate. Any modification in torque, while performing
your pin manipulations may cause a greater force against these aligned
pins thus disturbing their proper alignment.
I have often wondered if the utilization of a mechanical pick gun with a
side to side motion across the pins would help. One would think that this
would increase your actual time spent vs. unique attempts. However I am
not sure if the pick gun would correctly reset the pins enough to allow
them to rotate.
I am interested in any information that people can offer with their experiences with Medeco(tm)
or any locks for that matter. If you have something to offer, please drop
me a line.
ANATOMY: WARDED LOCKING MECHANISMS
The premise of warded locks has existed for centuries. They were one of the first
practical lock designs in history. Like most locks their exists many variations
of this type however most of them conform to the same basic design.
Although at first glance warded padlocks appear similar to the pin tumbler padlocks
that we have discussed thus far. Internally however, they are quite
different.
Let's take a look..
The simplistic design of the locking mechanism in warded locks make them an excellent
choice for the outdoors where a little bit of water and the subsequent
rust won't hurt their "far from precision" moving parts.
These locks are
unfortunately stricken with security flaws. The most apparent of which
is the amount of levers that secure the bolt. Their is usually one single
action an one dual lever and from what I have seen this appears to be the
norm for almost all warded locks.
In some cases their will just be the
upper dual lever securing the bolt.
So how do we pick these locks?
Warded padlocks aren't really picked per se. Although it would be possible to
use a couple of pieces of "L" shaped rolled steel to fiddle around
with the levers until you perpendicularly depressed all levers present;
it would be much easier to use a key blank such as the ones in figure 27.
The second from right blank on that key ring (figure 27) will open most of the warded
padlocks that you may encounter. If this is not the case, insert your blank
(second or third from left) into the lock ~1/8" and gently turn it clockwise checking for any resistance. If none is
felt proceed further into the keyway (1/8" steps) taking note at which
levels resistance is felt. Once you have established the number of levers
present and at which depth they occur, it is a simple matter of stacking
blanks to mimic the positions.
One of the security features present on warded locks is the association between
the plate that comprises the keyway and the key itself. The keys for these
locks are not flat. They are slightly "Z" shaped and vary in thickness,
width, and length.
The arrangment of the stubs on these keys also vary
in width and positioning.
This system is a poor one. If we look at figure 28, those keys will still open their
respective locks, even though i removed all but two of the stubs. If I
further removed some material from the key on top and made it flat so that
it may enter the key way of the other lock, it will open both locks and
probably most warded locks available.
ANATOMY: TUBULAR LOCKS
I am just getting into this area so I will post some information as it arises. From
what I can ascertain as of yet is that they are a real pain to pick. Requiring
the person to pick the lock more than once (5 times) comes to mind just
to open it. They also must be picked to be closed.
There are picks on the market that can make this process quite simple, unfortunately
they have a hefty price tag. So, until I get some time to analyze this
type of lock a little further, this section will remain quite short.
What I do know is that they make tubular drills that remove the pins from the
cylinders in these babies. Sounds like a more direct approach to me.
CONSIDERATIONS: THE MORAL OF THIS STORY
My reasons for the effort expended on this web page was for two reasons really. For
starters; picking locks happens to relax me and I wanted to test out my
new digital camera. Secondly I wanted to dispel any thoughts
that some of you might have that a typical lock is actually secure.
Am I wrong to disclose information such as this? Let's consider for a moment the IQ of
a typical criminal that would break into your house. It is probably far
lower than 50 (I have no statistical information to support this but I
assume it is close).
Now, do you think they are going to be picking the
dead bolt on your front door? The odds are probably 1 in 10,000. Assuming
the low IQ of this individual he/she is probably illiterate and would
never have the means to assimilate this type of information nor the brain
capacity to comprehend it if they came across it. They may however,
if walking erect and possessing some basic motor skills notice your
bay window and throw a brick through it. Or, if their cognitive skills
were slightly more advanced they may make use of a simple lever like a
pry bar and test the tensile strength of your front door.
In their simplest form a lock is merely a deterrent. Analogous to the "Do Not Enter" signs that
we see so regularly. If you think for one minute that a lock is protecting
your privacy or your valuables you are sadly mistaken. Like that sign they
are merely a simple visual aid that relay's a message, only with a little
more gusto.
If you take a walk around your home, or your car, or that little
cedar chest that you use in lieu of a safety deposit box at a bank you
will likely notice that with a little bit of creative thinking, there are
numerous ways to bypass the locking mechanisms that you rely on.
Know the value of that which you are trying to protect and act accordingly.
Consider some of the following:
- Most locks can be picked. So buy a decent one.