Another question about masterkeying

[Don Burke]

I read here that the masterkey should have one cut that is the shallowest used in the system and one cut that is the deepest in the system.

I understand the shallowest cut - that forces a "rights amplifier" to track down blanks.

What is the logic behind using the deepest cut?

[xeo]

I don't know but I'd think you'd want the master key bitting to be higher than all other keys so the user can't file down their key to a master key. I think that is a moot point though as if you have that level of skill you can use various other methods for privilege escalation.

[GWiens2001]

It is a good idea to have some bittings higher and some lower on SFIC or LFIC locks so that someone would have a harder time picking or impressioning it. Unless they are Xeo, in which case you may as well leave the keys in the lock.

Gordon

[jharveee]

perhaps lowest cut would allow you to start your keying matrix at 0 and build up from there. Sure I did not explain that well. first change key would be 00000 then next change key could be 00002, 00004 and so no.

[selim]

Nope , there's plenty about the kba of a system online.
Try the doownloadable corbin russwin cylinder manual

[Master Keying]

I read here that the masterkey should have one cut that is the shallowest used in the system and one cut that is the deepest in the system?

That is correct.

I understand the shallowest cut - that forces a "rights amplifier" to track down blanks.

What do you mean by this ?

What is the logic behind using the deepest cut?

See XEO comment..

I don't know but I'd think you'd want the master key bitting to be higher than all other keys so the user can't file down their key to a master key. I think that is a moot point though as if you have that level of skill you can use various other methods for privilege escalation.

Correct

It is a good idea to have some bittings higher and some lower on SFIC or LFIC locks...

Its very good idea to have it.

...so that someone would have a harder time picking or impressioning it.

Yes and No. It depends if the position/s are constant or not.

Example 1:
Master code would be 527416, and we will progress our CK's in last 3 positions. Then Yes its harder to pick it, because first 3 positions (527) are constant. Its a bit difficult to go "through" larger pins.

Example 2:
Master code would be 527416, and we will progress our CK's in first 3 positions. Then No, its easier to pick because you will have more shear lines at the start.

It's also good practice to use odd/even cuts.

perhaps lowest cut would allow you to start your keying matrix at 0 and build up from there. Sure I did not explain that well. first change key would be 00000 then next change key could be 00002, 00004 and so no.

Many Locksmiths / Non-locksmiths do it this way. I'm not saying it as a wrong way of doing it, but definitely not the right one.
As one of the "Rules" is to use highest and lowest code/cut if/when possible - in your MK.
So, it this case what would be your Master Key code?

[jharveee]

having the shallowest and the deepest seem to be creating MACs, So why have the deepest? So your key has an aggressive profile?
I like the example of the first three being constant, it gives you a place to expand your system when needed.

[jharveee]

Back when master keying was invented there were only two size pins. Deep and shallow. So it became rule to use both in your master key.

[MrWizard]

[xeo]

[Don Burke]

I understand the shallowest cut - that forces a "rights amplifier" to track down blanks.

What do you mean by this ?

Using a master key with all deeper cuts would allow a bad guy to file down an existing change key to make a master. Using at least one shallower cut means that a change key would have to be built up to get to the master shear line. Forcing the bad guy to either go through that process or get a blank adds more work on his end. It's not a massive increase in security, but it does make things a bit harder with little effort on the locksmith's part. I would agree this is a minor point, but I don't think it is moot.

What is the logic behind using the deepest cut?

See XEO comment..

Now it is my turn to ask what you mean by this. Xeo appears to be reconfirming the part that I already understand.

It's also good practice to use odd/even cuts.

Since you brought it up, I'll ask about this one too. In some places I have seen a recommendation that either all even cuts or all odd cuts be used. The only advantage to that I can see is that it eliminates the possibility of using a "1" master pin. It would seem that it would not be all that difficult to manage that possibility out of the system, but I have zero experience at very large keying systems, so I could easily be missing something.

[Don Burke]

Nope , there's plenty about the kba of a system online.
Try the doownloadable corbin russwin cylinder manual

Thanks for this tip. That will keep me reading for quite a while.

http://www.corbinrusswin.com/Other/Corb ... /45078.pdf

[GWiens2001]

Gordon

[jeffmoss26]

Don...the manual you want is this:
http://extranet.assaabloydss.com/librar ... .11.09.pdf

[Don Burke]

Don...the manual you want is this:
http://extranet.assaabloydss.com/librar ... .11.09.pdf

...and yet another massive resource is revealed.

Thanks