masterkey systems / locks - how do they work?

[gr00ve]

i understand that there are multiple pins in a pinstack when there is a masterkey system. but im just applying this to the system my school uses of Best locks.

*I AM NOT TRYING TO PICK THEM, IM ASKING JUST OUT OF CURIOSITY!*

my key as well as everyone else living in my suite has the same cut in our 5-6-7th pins. theres a main door to the suite which we can all open as well 3 individual doors for our rooms.

my questions are.
a. our main door seems to have 7 pins but all of our keys open it
b. the masterkey opens every door in the building how? does each pinstack have multiple shear lines?

[ToolyMcgee]

The correct answer is B.

Somehow I think you already knew that.

[WOT]

i understand that there are multiple pins in a pinstack when there is a masterkey system. but im just applying this to the system my school uses of Best locks.

*I AM NOT TRYING TO PICK THEM, IM ASKING JUST OUT OF CURIOSITY!*

my key as well as everyone else living in my suite has the same cut in our 5-6-7th pins. theres a main door to the suite which we can all open as well 3 individual doors for our rooms.

my questions are.
a. our main door seems to have 7 pins but all of our keys open it
b. the masterkey opens every door in the building how? does each pinstack have multiple shear lines?

It's quite possible there is one or more missing stack on the suite door. Such an arrangement is made so that if you lose your key, your room can be rekeyed without causing your roommates' key to be disabled from the suite door.

The exact configuration depends on the entire system.

[gr00ve]

oh empty stacks... so like 1-4 would be empty and 5-7 works? i definitely feel 7 pins when im putting the key in. ok thats all i wanted to know.. im just trying to figure this out because if all of my suitemates keys are different, but one masterkey opens every door, how different can each lock/key be

[raimundo]

Un masterkeyed, the collumn contains a spring, a top pin, a shear line, and a bottom pin. the only key that will work is the one that satisfies the shearline.

masterkeyed, the collumn contains a spring, a top pin, a shearline, a middlepin, a shearline, and a bottom pin. OMG, theres two shearlines there.

grandmaster and submaster keyed, has spring, top pin, shearline, masterkeypin, shearline, another masterkeypin, shearline, bottom pin. OMG theres three different shearlines in there. Three different key cuts will open this collumn. fortunatly there are other collumns in the lock, some may be masterkeyed and some may be just two pins with no middle pin.

masterkeyed locks, except the corbin ring cylinder, that you will no longer encounter if its not an old hotel building, will have extra shearlines in the pin collumn that make the lock less secure.

If you are picking a lock that you know to be masterkeyed, when you turn the plug 108 degrees, there is the possibility of one of the thin middle pins falling into the bottom of the keyway that would normally be filled with key,

you could prevent this by holding a pick shaft in the bottom as you pass the 180 degree area,

If you cause the master pin to drop into the keyway, you are in big trouble, You cannot know for sure which collumn it came from as some collumns have more than one of these middle pins, You will have to dissasemble the lock to replace the pin, and to know where it belongs, you will need copies of all the master, grand master and individual keys that apply to it.
So don't screw around with masterkeyed locks in use.

[globallockytoo]

i understand that there are multiple pins in a pinstack when there is a masterkey system. but im just applying this to the system my school uses of Best locks.

*I AM NOT TRYING TO PICK THEM, IM ASKING JUST OUT OF CURIOSITY!*

my key as well as everyone else living in my suite has the same cut in our 5-6-7th pins. theres a main door to the suite which we can all open as well 3 individual doors for our rooms.

my questions are.
a. our main door seems to have 7 pins but all of our keys open it
b. the masterkey opens every door in the building how? does each pinstack have multiple shear lines?

Rai's explanation is on the money.

But to answer the questions:
a: your system is "maison" keyed.
Maison keying, creates multiple shearlines inside a cylinder, where in theory, all keys in a system will access a communal door. The door will remain lockable without a key inserted but the quality of the security is much lower because the cylinder can be manipulated more easily.
However, systems like Abloy and Bilock do not require multiple pin stacks, effectively maintaining the same height of security as a non-masterkeyed cylinder.

b: of course, this is how come it is called a master key system.

[WOT]

Un masterkeyed, the collumn contains a spring, a top pin, a shear line, and a bottom pin. the only key that will work is the one that satisfies the shearline.

Typically, but the lock being discussed here is different. SFIC locks contain a minimum of three pins per chamber. Bottom, build-up, and top and there are two shear lines, operating, and control(which is used for removing the core).

masterkeyed, the collumn contains a spring, a top pin, a shearline, a middlepin, a shearline, and a bottom pin. OMG, theres two shearlines there.

There is only one operating shearline. There are two shearlines on SFIC locks, but that is something unique to SFIC and locks with a separate master ring.

grandmaster and submaster keyed, has spring, top pin, shearline, masterkeypin, shearline, another masterkeypin, shearline, bottom pin. OMG theres three different shearlines in there. Three different key cuts will open this collumn. fortunatly there are other collumns in the lock, some may be masterkeyed and some may be just two pins with no middle pin.

You only put more than two operating cuts when you have get a lock to accept many different change keys. A lock with chambers combinated to accept:
1,1,1,1,1,1
3,3,3,3,3,3
can still have many layers of keys.

i.e. let 1,1,1,1,1,1 be grand master
3,3,3,3,3,3 be change
3,3,3,3,3,1 could be set up as a master for the suite set for example

masterkeyed locks, except the corbin ring cylinder, that you will no longer encounter if its not an old hotel building, will have extra shearlines in the pin collumn that make the lock less secure.

If you are picking a lock that you know to be masterkeyed, when you turn the plug 108 degrees, there is the possibility of one of the thin middle pins falling into the bottom of the keyway that would normally be filled with key,

you could prevent this by holding a pick shaft in the bottom as you pass the 180 degree area,

If you cause the master pin to drop into the keyway, you are in big trouble, You cannot know for sure which collumn it came from as some collumns have more than one of these middle pins, You will have to dissasemble the lock to replace the pin, and to know where it belongs, you will need copies of all the master, grand master and individual keys that apply to it.
So don't screw around with masterkeyed locks in use.

SFIC master key systems designed by Best Access Systems follow a strict set or rules, so they're quite predictable. Each stack adds up to the same height, so if you miss a master pin, you'd be able to tell where it came from by measuring the height, then locating the stack that does not add up to spec height,then checking the difference against the lost pin. If they match, then you know where to put the lost pin.

[ridinplugspinnaz]

It's quite possible there is one or more missing stack on the suite door. Such an arrangement is made so that if you lose your key, your room can be rekeyed without causing your roommates' key to be disabled from the suite door.

The exact configuration depends on the entire system.

Wow, that's a fascinating (and ingenious) way to accomplish that design goal. Submastering by removing pin stacks? It strikes me as very curious that the supposedly "submastered" lock (insofar as that multiple change keys open it) is actually less secure than the lowest-level room door locks, by virtue of a pin stack missing. Is that a common occurrence among cylinders in a master-keyed system where lots of people need access to specific doors, but between that group key loss is a probable?

Seriously, that's a fascinating way to go about solving the problem, even if it does end up trading security for convenience. I guess that's why SFICs tend to have so many pin stacks?

[WOT]

Wow, that's a fascinating (and ingenious) way to accomplish that design goal. Submastering by removing pin stacks? It strikes me as very curious that the supposedly "submastered" lock (insofar as that multiple change keys open it) is actually less secure than the lowest-level room door locks, by virtue of a pin stack missing.

Any master keying is convenience at the expense of security. If it's for a wing containing say, 20 rooms, it isn't that important to keep the door to the wing as secure as rooms, so it's acceptable for the wing lock to missing a stack or two, or some stacks to have more than 2 operating depths to accommodate around all 20 keys + sufficient number of rotation cores.

Is that a common occurrence among cylinders in a master-keyed system where lots of people need access to specific doors, but between that group key loss is a probable?

If the door must be accessible by a large number of people, the common practice is to issue two separate keys, everyone the same lowest level change key for outside, and change key for their apartment.

Since you can't change the outside lock everyone someone loses their key, it's not a bad idea to use electronic system for the exterior, single key for each room, then a casual lock with lots of stacks missing for areas where security is not that important, but use must be restricted to tenants (such as restrooms and laundry rooms)

The complexity depends on the system. For a dorm, you'd probably have a floor master, maintenance master, building master, and perhaps great-grand master that opens every door across multiple buildings.

Seriously, that's a fascinating way to go about solving the problem, even if it does end up trading security for convenience. I guess that's why SFICs tend to have so many pin stacks?

Newer SFICs have 7-pins as their target market is large master keyed systems.

[globallockytoo]

Any master keying is convenience at the expense of security. If it's for a wing containing say, 20 rooms, it isn't that important to keep the door to the wing as secure as rooms, so it's acceptable for the wing lock to missing a stack or two, or some stacks to have more than 2 operating depths to accommodate around all 20 keys + sufficient number of rotation cores.


If the door must be accessible by a large number of people, the common practice is to issue two separate keys, everyone the same lowest level change key for outside, and change key for their apartment.

Since you can't change the outside lock everyone someone loses their key, it's not a bad idea to use electronic system for the exterior, single key for each room, then a casual lock with lots of stacks missing for areas where security is not that important, but use must be restricted to tenants (such as restrooms and laundry rooms)

The complexity depends on the system. For a dorm, you'd probably have a floor master, maintenance master, building master, and perhaps great-grand master that opens every door across multiple buildings.

Seriously, that's a fascinating way to go about solving the problem, even if it does end up trading security for convenience. I guess that's why SFICs tend to have so many pin stacks?

Newer SFICs have 7-pins as their target market is large master keyed systems.

I disagree to a degree. Master keying does not have to decrease the perceived level of security for convenience. Yes it does with many existing pin tumbler systems like Best or Schlage or Assa or Medeco, but systems like Abloy or Bilock do not encounter the same security deficiencies through master keying and maintain the convenience ability sufficiently, without the need to remove pin stacks or leave chambers empty.

With Bilock systems....it is very simple to replace a key in a system without affecting the other keys in the system (dependent on size of system of course), so rekeying a common entry door, while maintaining the other "non-lost" keys is in fact a simple, quick and cost effective practise.

[WOT]

I disagree to a degree. Master keying does not have to decrease the perceived level of security for convenience. Yes it does with many existing pin tumbler systems like Best or Schlage or Assa or Medeco, but systems like Abloy or Bilock do not encounter the same security deficiencies through master keying and maintain the convenience ability sufficiently, without the need to remove pin stacks or leave chambers empty.

With Bilock systems....it is very simple to replace a key in a system without affecting the other keys in the system (dependent on size of system of course), so rekeying a common entry door, while maintaining the other "non-lost" keys is in fact a simple, quick and cost effective practise.

I have no knowledge of master keying with rotating tumbler locks like the ASSA/ABLOY Protec and such and Bilock appears to be two rows of pin & tumblers.

Here's my take... any given purely mechanical lock cylinder is designed around specific keys while electronic locks can be designed to accommodate any key.

Even if the locks don't go to the extreme of missing chambers, if each stack can accept more than one operating bittings, there are two or more positions that will operate that stack, so it makes it easier to pick.

If each lock is sufficiently difficult to pick, every mechanical lock under the same master key system is related, only a handful of keys and cylinders can reveal the key that will operate all of them.

Since Suite A,B, & C in a dorm is under the same master key system, it's very possible that the key for suite A in conjunction with lock A can derive the master.

[ridinplugspinnaz]

Any master keying is convenience at the expense of security. If it's for a wing containing say, 20 rooms, it isn't that important to keep the door to the wing as secure as rooms, so it's acceptable for the wing lock to missing a stack or two, or some stacks to have more than 2 operating depths to accommodate around all 20 keys + sufficient number of rotation cores.


If the door must be accessible by a large number of people, the common practice is to issue two separate keys, everyone the same lowest level change key for outside, and change key for their apartment.

Since you can't change the outside lock everyone someone loses their key, it's not a bad idea to use electronic system for the exterior, single key for each room, then a casual lock with lots of stacks missing for areas where security is not that important, but use must be restricted to tenants (such as restrooms and laundry rooms)

The complexity depends on the system. For a dorm, you'd probably have a floor master, maintenance master, building master, and perhaps great-grand master that opens every door across multiple buildings.

Seriously, that's a fascinating way to go about solving the problem, even if it does end up trading security for convenience. I guess that's why SFICs tend to have so many pin stacks?

Newer SFICs have 7-pins as their target market is large master keyed systems.

I disagree to a degree. Master keying does not have to decrease the perceived level of security for convenience. Yes it does with many existing pin tumbler systems like Best or Schlage or Assa or Medeco, but systems like Abloy or Bilock do not encounter the same security deficiencies through master keying and maintain the convenience ability sufficiently, without the need to remove pin stacks or leave chambers empty.

With Bilock systems....it is very simple to replace a key in a system without affecting the other keys in the system (dependent on size of system of course), so rekeying a common entry door, while maintaining the other "non-lost" keys is in fact a simple, quick and cost effective practise.

Your assertion here confuses me (probably cause I know next to nothing about higher-security locks). But in a system like the Abloy, don't you still need to provide additional cuts in the disc so that a keys of different bittings will both open the lock? If that's true, I don't see how that doesn't decrease security since you are enabling a greater number of combinations that will yield an open cylinder. Also, as WOT said, I was under the impression that BiLocks are basically just two parallel pin-tumbler keyways integrated into the same lock. How do they work differently from regular pin-tumbler locks other than that there's more of them, and such that mastering them doesn't decrease security?

Sorry if I'm asking anything above this forum's pay grade, if I am just point it out so I know what to stop asking...

[BobbO45]

Even if the locks don't go to the extreme of missing chambers, if each stack can accept more than one operating bittings, there are two or more positions that will operate that stack, so it makes it easier to pick.

Please correct me if I am mistaken, but I believe that this is not necessarily true. In a SFIC lock there are two shear lines, one for the operator key, and one for the change key. All of the pin stacks have to line up at either one or the other for the plug to rotate. Having more pins in the lock lowers your chances of picking all of the pins to either one shear line or the other (to an extent). If six of the pins are set to the operator shear line, and just a single stack is picked to the depth of the change key then the lock will not open. It is much easier to pick a stack to the wrong shear preventing the lock from opening when there are more pins in the lock (in the case of an SFIC).

Another quesion: How many different depths do Best locks have (to how many different depths can you code cut a best key)? Are there pin depths from 1 to 6, 9, 15? Just trying to get an idea for how many different possibilities there are for pinning a best lock. Thanks!

[globallockytoo]

Even if the locks don't go to the extreme of missing chambers, if each stack can accept more than one operating bittings, there are two or more positions that will operate that stack, so it makes it easier to pick.

Please correct me if I am mistaken, but I believe that this is not necessarily true. In a SFIC lock there are two shear lines, one for the operator key, and one for the change key. All of the pin stacks have to line up at either one or the other for the plug to rotate. Having more pins in the lock lowers your chances of picking all of the pins to either one shear line or the other (to an extent). If six of the pins are set to the operator shear line, and just a single stack is picked to the depth of the change key then the lock will not open. It is much easier to pick a stack to the wrong shear preventing the lock from opening when there are more pins in the lock (in the case of an SFIC).

Another quesion: How many different depths do Best locks have (to how many different depths can you code cut a best key)? Are there pin depths from 1 to 6, 9, 15? Just trying to get an idea for how many different possibilities there are for pinning a best lock. Thanks!

Okay....i didnt write that but...

You can pick the lock to the control position and remove the core....negating the need to pick it to open....once removed just turn the mechanism with a screwdriver or pliers.

The more pins in a chamber increases the likelihood of the cylinder being picked easily....not the other way around as you suggest.

I think Best core stack need to add up to 23 per chamber....I dont do much SFIC....so I cant be sure.

[globallockytoo]

I disagree to a degree. Master keying does not have to decrease the perceived level of security for convenience. Yes it does with many existing pin tumbler systems like Best or Schlage or Assa or Medeco, but systems like Abloy or Bilock do not encounter the same security deficiencies through master keying and maintain the convenience ability sufficiently, without the need to remove pin stacks or leave chambers empty.

With Bilock systems....it is very simple to replace a key in a system without affecting the other keys in the system (dependent on size of system of course), so rekeying a common entry door, while maintaining the other "non-lost" keys is in fact a simple, quick and cost effective practise.

Your assertion here confuses me (probably cause I know next to nothing about higher-security locks). But in a system like the Abloy, don't you still need to provide additional cuts in the disc so that a keys of different bittings will both open the lock? If that's true, I don't see how that doesn't decrease security since you are enabling a greater number of combinations that will yield an open cylinder. Also, as WOT said, I was under the impression that BiLocks are basically just two parallel pin-tumbler keyways integrated into the same lock. How do they work differently from regular pin-tumbler locks other than that there's more of them, and such that mastering them doesn't decrease security?

Sorry if I'm asking anything above this forum's pay grade, if I am just point it out so I know what to stop asking...

Bilocks use only one set of bottom pins.....no separate master pins or driver pins....

Only bottom pins.

The master pins are simply normal pins with extra holes in them for multiple positions/shear lines.

Picking means, picking one pin per chamber x 12 chambers + the extra sidebar blocking pin. The sidebar blocking pin usually needs to be set first to allow the right hand sidebar to depress before the left hand sidebar.