Extra holes in cheap 5 pin residential lock core

[hydruh]

Though this is probably a n00b question, I can't immediately see the point of the four extra holes in this lock:



Is this a picking defense?

S

[CaptHook]

http://www.locksmithcharley.com/builderkey.html
Chuck

[hydruh]

Wow, that is AMAZING! I have been doing this for how long? And I have never, ever heard of that!

Thanks a lot! Interesting site, that you?

S

[pjzstones]

that's pretty cool i've wondered the same thing but never really thought too much about it.

[CaptHook]

Not me. I dont wear tie dye.
Chuck

[jwhou]

Those are dimples for the protecto balls. Basically the key would be master-keyed using "protecto balls" which are small ball bearings and the master key would be given to contractors such as electricians and plumbers during construction of the house. These "builder's" keys would shear above the ball bearings keeping the ball s in the pinstack inside the plug. When the homeowner's keys is used, they push the ball bearings up into the bible shearing below the ball bearings and as the plug is rotated, the top drivers push these balls into the dimples where they remain trapped thereby disabling the builder's keys. The problem is that regular master pins are also used so that an entire neighborhood can be opened with the same "builder's" key and even after the homeowner's keys have been used on all the locks in the house, it's a trivial matter for someone to make a set of five keys based upon the "builder's" keys such that one of them would be a master for the neighborhood after the balls had been trapped. This is a good reason to re-key all your locks on a new house even if it's just re-keyed to your existing key, note that you need to pull the top pins out too cause most of the master keying is such that the master pins are all pushed into the bible when the homeowner's key is used. I came across two different sizes of "protecto balls" when re-keying my house, if I had been a bit more careful, I could've recorded the bitting of a master key that would've opened my neighbour's houses but I'm too scrupulous to do that or rather too careless.

[MacGyver101]

Here

Wow... that's quite the page of misinformation. (Although I'm sure it sells locks.)

I've never heard of construction-key ball bearings referred to as "master pins" before:

Your locks, stuffed with master pins, are likely very insecure.

I'm also not entirely clear on how the Protecto bearings continue to make your lock "very insecure" once the owner's key has been used... and I have no idea how master-keyed locks suddenly come into his discussion (other than to raise some additional unfounded fear):

If the locks are pinned up with one master pin in each chamber [...] that makes the total number of keys able to open that lock 64.

Actually, it would be 243 keys for a five-pin cylinder with both a single master wafer and a set of Protecto bearings in each pin stack (3 to the power of 5), or 729 keys in a six-pinned cylinder like the one he shows in the photograph. (If we want to continue the fear-mongering further, you could remove five of the six pinstacks and then there would be... 50,421 factory-cut keys that could open YOUR front door!!!!!!!!)

Notwithstanding that, he then suggests that you can somehow use this information to make a master key for your entire subdivision:

Quite simply that anyone with a small level of knowledge about locks can very quickly & easily, with one lock and one house key, determine the cuts of a key (not the locked out builder’s key) that will act as a master key that will likely open not only YOUR home, but also some or all of the houses in the subdivision.

That's clearly preposterous, unless he's assuming that every lock in the subdivision is keyed the same... in which case, you don't need to bother with disassembling the lock: your actual house key would open everyone else's door.

If I'm reading the keying manual correctly, the construction-keying balls add two cut depths to the key, and you can put the balls into any number of the chambers. So, using the cylinders he has in the photographs, your pinning options are:

• 1 pin stack with Protecto balls: (6 choose 1) = 6 ways to key that. (chamber 1, 2, 3, 4, 5 or 6)
• 2 pin stacks with Protecto balls: (6 choose 2) = 15 ways to key that. (chambers 1 and 2, 1 and 3, 1 and 4, etc.)
• 3 pin stacks with Protecto balls: (6 choose 3) = 20 ways to key that. (chambers 1 and 2 and 3, 1 and 2 and 4, etc.)
• 4 pin stacks with Protecto balls: (6 choose 4) = 15 ways to key that.
• 5 pin stacks with Protecto balls: (6 choose 5) = 6 ways to key that.
• 6 pin stacks with Protecto balls: (6 choose 6) = 1 way to key that.

Which adds up to 63 possible "owner" keys that could correspond to any given construction key. For example, if the construction key was cut to "111111", you could have owner keys of:

• 111113 (balls in only the last chamber)
• 111131 (balls only in the second-last chamber)
• 111311 (balls only in the fourth chamber)
• 131331 (balls in the second, fourth and fifth chambers)
• etc., etc..

Now, granted that's not very many key differs, assuming that there's only one builder's key... but 63 is far greater than 1, and it's nowhere near the "anyone with a small level of knowledge and access to someone else's lock can make a master key for YOUR home" level of panic.

Despite its claims of being "presented as a public service", the math is rubbish and the facts are clearly distorted to panic people into buying this guy's services.

Shameful.

[hydruh]

But the description is correct. That is what the balls are for, and they do reduce the security somewhat. Just not nearly to the extent that the author proposes. Right?

S

[MacGyver101]

But the description is correct. That is what the balls are for, and they do reduce the security somewhat. Just not nearly to the extent that the author proposes. Right?

Well, yes and no. The description of how the balls work is correct: they're like a special sort of master-key wafer that gets "eaten" by the lock when the change key is first used.

And (unlike generic master-key wafers) because they're a fixed size, they constrain the difference between the construction key and the owner's key... so, in that sense, yes: they greatly reduce the number of key differs that are possible between the two keys. (So, given one owner's key, you could construct the 63 other keys: one would be the construction key, and one of the other 62 (or your own key) would open any other locks that shared the same construction key.)

Now... if you're carrying around 63 keys just to open a Kwikset front door lock...

[jwhou]

Here

Wow... that's quite the page of misinformation. (Although I'm sure it sells locks.)

I've never heard of construction-key ball bearings referred to as "master pins" before:

Actually, I think that describing protecto balls as a master pin is accurate. A master pin allows for there to be a shear line above and below the master pin and a protecto ball does the same. The difference is that a protecto ball becomes trapped and hence removed from the stack by the dimples if a key shears just below the protecto ball allowing one key to effectively remove the mastering that allows the other to work. Of course, there are limitations as to the size of the protecto balls (I found two different sizes in use in my house locks) as they have to fit into the dimple.

Your locks, stuffed with master pins, are likely very insecure.

I'm also not entirely clear on how the Protecto bearings continue to make your lock "very insecure" once the owner's key has been used... and I have no idea how master-keyed locks suddenly come into his discussion (other than to raise some additional unfounded fear):

As with any mastering, if the keys are to differ by more than one bitting, multiple master pins or protecto balls must be introduced in multiple pin stacks which increases the number of bitting patterns that can open the lock hence making the lock insecure. Of course having the keys intended to open the lock differ by only one bitting position is also insecure as then the restricted key is almost identical to the unrestricted use key. Keying for contractor's usually involve a mix of master pins and protecto balls in order that the contractor keys work on multiple houses and are not representative of what the homeowner's key bitting will be. Unfortunately that means that although the balls get removed from the pin stack, the master pins do not hence the locks in the neighborhood can still be open by a bitting pattern that has not been distributed yet. It's trivial to cut a set of five keys from a builder's key, one of which will open an entire neighborhood of houses after the homeowner's keys have been used. It's adviseable to re-key locks after the locks have been installed by construction workers. Even my front door lock which was installed after the sale and hence after there was a need for construction keying had both protecto balls and master pins in it.

I don't think I see how the previous posts was encouraging additional sales of locks, if anything it encouraged re-keying of existing locks which is good security advice.

If the locks are pinned up with one master pin in each chamber [...] that makes the total number of keys able to open that lock 64.

Actually, it would be 243 keys for a five-pin cylinder with both a single master wafer and a set of Protecto bearings in each pin stack (3 to the power of 5), or 729 keys in a six-pinned cylinder like the one he shows in the photograph. (If we want to continue the fear-mongering further, you could remove five of the six pinstacks and then there would be... 50,421 factory-cut keys that could open YOUR front door!!!!!!!!)

Notwithstanding that, he then suggests that you can somehow use this information to make a master key for your entire subdivision:

Quite simply that anyone with a small level of knowledge about locks can very quickly & easily, with one lock and one house key, determine the cuts of a key (not the locked out builder’s key) that will act as a master key that will likely open not only YOUR home, but also some or all of the houses in the subdivision.

That's clearly preposterous, unless he's assuming that every lock in the subdivision is keyed the same... in which case, you don't need to bother with disassembling the lock: your actual house key would open everyone else's door.

If I'm reading the keying manual correctly, the construction-keying balls add two cut depths to the key, and you can put the balls into any number of the chambers. So, using the cylinders he has in the photographs, your pinning options are:

• 1 pin stack with Protecto balls: (6 choose 1) = 6 ways to key that. (chamber 1, 2, 3, 4, 5 or 6)
• 2 pin stacks with Protecto balls: (6 choose 2) = 15 ways to key that. (chambers 1 and 2, 1 and 3, 1 and 4, etc.)
• 3 pin stacks with Protecto balls: (6 choose 3) = 20 ways to key that. (chambers 1 and 2 and 3, 1 and 2 and 4, etc.)
• 4 pin stacks with Protecto balls: (6 choose 4) = 15 ways to key that.
• 5 pin stacks with Protecto balls: (6 choose 5) = 6 ways to key that.
• 6 pin stacks with Protecto balls: (6 choose 6) = 1 way to key that.

Which adds up to 63 possible "owner" keys that could correspond to any given construction key. For example, if the construction key was cut to "111111", you could have owner keys of:

• 111113 (balls in only the last chamber)
• 111131 (balls only in the second-last chamber)
• 111311 (balls only in the fourth chamber)
• 131331 (balls in the second, fourth and fifth chambers)
• etc., etc..

Now, granted that's not very many key differs, assuming that there's only one builder's key... but 63 is far greater than 1, and it's nowhere near the "anyone with a small level of knowledge and access to someone else's lock can make a master key for YOUR home" level of panic.

Despite its claims of being "presented as a public service", the math is rubbish and the facts are clearly distorted to panic people into buying this guy's services.

Shameful.

On the contrary, it is possible to make a set of five keys (or six keys for 6 pin locks) of which one would function as a master for the houses by the same builder. This is because in addition to the construction keying by the use of protecto balls, master pins are likely used so that only one builder's key need to be issued for each contractor for all the homes by the same builder rather than issuing a different builder's key for each home. Of course if the builder did issue a different builder's key for each home to all the contractors then it wouldn't be possible to make a key for the entire neighborhood but since neither the builder nor the workers he hires wishes to carry several hundred keys, this doesn't happen.

As with any master keying, although the intent is to make another key bitting work, with each master pin in a pin stack you are allowing multiple patterns work. If there is a master pin in each of the five pin stack, there would be 2^5 key patterns that would work even though only two were distributed, that's 32 keys. You don't even have to get the master key right in order for it to be the master key to the neighborhood, there's 30 other bitting patterns that may serve the same function for at least some of the houses.

I'm sorry but following your responses to lock charley's posting does not paint him as a fear mongering or marketeer nor as having the facts wrong. You on the other hand...

[jwhou]

But the description is correct. That is what the balls are for, and they do reduce the security somewhat. Just not nearly to the extent that the author proposes. Right?

Well, yes and no. The description of how the balls work is correct: they're like a special sort of master-key wafer that gets "eaten" by the lock when the change key is first used.

And (unlike generic master-key wafers) because they're a fixed size, they constrain the difference between the construction key and the owner's key... so, in that sense, yes: they greatly reduce the number of key differs that are possible between the two keys. (So, given one owner's key, you could construct the 63 other keys: one would be the construction key, and one of the other 62 (or your own key) would open any other locks that shared the same construction key.)

Now... if you're carrying around 63 keys just to open a Kwikset front door lock...

So let's get this straight. First you say you don't understand how protecto balls can be described as master pins and then now you describe them as a master pin that gets eaten (an analogy that I would agree with).

Perhaps you should work on consistency.

With one protecto ball in a stack and one master pin in each stack to allow a builder's master key for the entire neighborhood, that would be 64 keys that could open the lock of which only one is the homeowner's key and the other 63 bitting patterns could be distributed as builder master keys. Now when the homeowner's keys removes that protector ball from one of the pin stacks, that builder's key is the wrong height in just one of the pin positions so only five keys need to be cut for the entire neighborhood not 63. Being able to examine a builder's key and then cut 5 keys to produce a neighborhood master is a security risk that many people are not aware of.

Look, this isn't a theory, it's been done. New construction masters can be any of 63 key bitting patterns and you only have to cut 5 keys before one of the five matches one of these 63 patterns. You don't need all the possible master keys, just one of them to open the locks. It's just like you only need to open one door to enter a house not all of them.

Your posting of carrying 63 keys around reminds me of the joke where the mechanic was feverishly trying to open the locked driver's side door while the passenger side was unlocked, when the fact that the passenger side was unlocked was pointed out he responded "Yeah, I already got that one unlocked.".

[MacGyver101]

Actually, I think that describing protecto balls as a master pin is accurate.

I guess it's a matter of semantics. They're neither a "pin", nor do they allow two or more keys to be used interchangeably... so I've just never heard the terms used interchangeably. (The two items certainly can't be used interchangeably?) And, yes: I did agree that they were "like a master wafer", but behaved differently than a master wafer does... but I don't think that's inconsistent?

On the contrary, it is possible to make a set of five keys (or six keys for 6 pin locks) of which one would function as a master for the houses by the same builder.

Hrm. Well, if your builder has pinned your front door lock so that there is a master key that opens it, then yes: master keys (and phantom masters) will exist. But that has nothing to do with the construction keying balls. I think that's a separate consideration from what both this thread and the website were initially discussing.

If "Locksmith Charlie" is concerned about master keys, then I'm not sure how construction keying balls factor into his discussion? He clearly tries to combine the two topics (incorrectly) by adding the 32 keys that can open a construction keyed locks with the 32 keys that can open a master-keyed lock... but construction keying balls simply don't factor into the security concern for an owner once they've used their key.

I'm sorry but following your responses to lock charley's posting does not paint him as a fear mongering or marketeer nor as having the facts wrong. You on the other hand...

Well, I take offense to that. I've seen nothing in the literature that says that in order to use construction keying you are obliged to secretly master-key an entire neighbourhood -- so, yes: I think that the broad claims on the website are irresponsible, but I'm not trying to fear-monger or market.

The only other "facts" I tried to introduce was math... and, I could be mistaken, but to me the math on the website appears to be simply wrong?

[jwhou]

On the contrary, it is possible to make a set of five keys (or six keys for 6 pin locks) of which one would function as a master for the houses by the same builder.

Hrm. Well, if your builder has pinned your front door lock so that there is a master key that opens it, then yes: master keys (and phantom masters) will exist. But that has nothing to do with the construction keying balls. I think that's a separate consideration from what both this thread and the website were initially discussing.

If "Locksmith Charlie" is concerned about master keys, then I'm not sure how construction keying balls factor into his discussion? He clearly tries to combine the two topics (incorrectly) by adding the 32 keys that can open a construction keyed locks with the 32 keys that can open a master-keyed lock... but construction keying balls simply don't factor into the security concern for an owner once they've used their key.

It may be unnecessary for the builder to master key their homes but they do simply because they do not want the key control issues of issuing as many builder's keys as they have homes under construction. Also without the master keying, the keys that they issue to the contractors would differ from the homeowners keys by just where the protecto balls were. It may not be necessary to master key a builder's key but it is an almost universal practice unless the builder only has one property under construction that he wishes to issue builder's keys for.

This means that the concept of builder's keys is usually not the only issue and most homeowner's are unaware that their locks have been master keyed. The master keying having not been removed by the homeowner's key.

A clever locksmith would use protecto balls in one pin chamber for some of his houses, in two for others, 3 for others, and even four or five in some houses such that the number of keys that might be the master increases from 5 to 36 but near as I can tell, it's common practice to just put protector balls in one chamber alone.

Using multiple protecto balls can also create a scenario where one builder's keys disables another builder's key's bitting thereby once the painter has started, the drywaller cannot re-enter the property with his key.

I'm sorry but following your responses to lock charley's posting does not paint him as a fear mongering or marketeer nor as having the facts wrong. You on the other hand...

Well, I take offense to that. I've seen nothing in the literature that says that in order to use construction keying you are obliged to secretly master-key an entire neighbourhood -- so, yes: I think that the broad claims on the website are irresponsible, but I'm not trying to fear-monger or market.

The only other "facts" I tried to introduce was math... and, I could be mistaken, but to me the math on the website appears to be simply wrong?

I do apologize for any offense taken, it's unfortunate but it is the nature of forum discussions to come across with less civility then we would in person. I would suspect that in person I would be glad to buy you a beer. However I think it is important to note that builder's that have more than one property under construction at a time will have secretly master keyed their properties and falsely present the builder's key concept as being why the properties are still secure which is what the web page said. I do believe that the recommendation on the website to purchase a high security lock as a solution is uncalled for but the recommendation of re-keying is a good and inexpensive idea for anyone who has purchased a property. I re-keyed my house for a total of $1.80, you really can't be that even though that's a 100% mark up on the pins that I bought and I really didn't need that many pins as many of the pins for the old bitting were the same pins in different orders.

I found Charlie's site to be informative and allow some degree of commercialness to it as it is a site belonging to a locksmith. It may be questionable whether Capt Hook should've linked to it in a public forum but I see no harm as it does appear to be descriptive of common builder's practices. I believe the important bit to take home is that it's best to take a little interest in how locks work and to take a look at the pinnings of your lock, leaving your security to strangers however professional is still leaving it to others whose primary motivation is not your security. I think you will agree with me that all else in our discussion in this thread is just typical forum banter. We may still disagree on whether or not Charlie's website is contributing useful and/or accurate information to the community but I believe that it does.

[MacGyver101]

I appreciate the virtual beer: thanks.

I'd not yet run across this master-keying practice in my neck of the woods -- but my total experience with it admittedly only extends to rekeying locks for three different homes that had originally been set up with builders keys, so it may just be too small a sample size... or simply an issue of differences in local practice from one area to another.

Either way, I trust that we've now exhaustively answered hydruh's original question.

[hydruh]

Either way, I trust that we've now exhaustively answered hydruh's original question.

I would say so!

Thanks everyone! And thanks for keeping it civil.

S