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Safe locks: Group 2 vs. Group 2M

PostPosted: Thu Apr 11, 2013 11:35 pm
by Libertyclicks
Safe Locks: Safe locks came arbitrarily in two groups initially. Now there are electronic locks as well which are more common now a days. There are Group 1, and Group 2. In between Group 1 and 2 safe locks are Group 2M locks.

Group 2

Group 2 locks meet certain requirements for mechanical tolerance and reliability. But have no special safe guards in place other than that. Group 2 locks have 3 wheels and are all turned sequentially using the dial on the front of the safe lock.
After I think the 50's or so a safe lock had to have a re-locker which would hold the safe lock shut in the event that a thief (or locksmith) drilled out the safe lock to gain relatively quick access. Safe locks can have suffixes depicting resistance to particular types of attacks. For example: a Group 2 M safe lock will resist expert manipulation usually for XX number of hours. Compare a Group 2 lock to a Group 2M lock:
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On the top is the coveted Sargent and Greenleaf 6700 Group 2 lock.
On the bottom, a relatively new brand "Big Red" Group 2M lock.
Both have relockers as mentioned, the metal arm on the bottom right of the lock.

Group 2M

The S&G lock is the same in design as the Big Red BUT....
The Big red has an extra plastic arm on a pivot with a spring connecting it to the lever of the lock. The drive cam on the Big Red has a roller which will actuate this plastic arm, causing it to "pull" the lever of the lock down into the drop in area ONLY when the drive cam is in the drop in area.

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The roller is pushing the plastic arm to the left, which is lowering the lever and fence onto the wheels. In this picture the nose touching the left contact point.

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The roller has pushed plastic arm, which is pulling the lever and fence down onto the wheels. In this picture the nose is touching the right contact point.

While readings can still theoretically be taken with this style, it is MUCH more difficult. The manipulator would have to know exactly how the lock is designed, and then hold enough back tension on the dial to stop the drive cam from rolling out from under the plastic arm, then measure miniscule differences in pressure, all while getting false indications from spring tension any time the lock is in the drop in area.

LibertyClicks

Re: Safe locks: Group 2 vs. Group 2M

PostPosted: Fri Apr 12, 2013 6:30 am
by xeo
Great info and pics, thanks for posting this.

Re: Safe locks: Group 2 vs. Group 2M

PostPosted: Fri Apr 12, 2013 11:18 am
by Oldfast
Nice!! Thanks for sharing. I've not experienced any beyond Group 2 yet... but thoroughly look forward to some frustration :D

S&G's Group 2M locks have what they call an 'eccentric roller' that's seated in the lever nose.
I can't quite tell from your pictures... but it doesn't look like that Big Red has this?

Re: Safe locks: Group 2 vs. Group 2M

PostPosted: Fri Apr 12, 2013 11:49 am
by Libertyclicks
Oldfast wrote:S&G's Group 2M locks have what they call an 'eccentric roller' that's seated in the lever nose.
I can't quite tell from your pictures... but it doesn't look like that Big Red has this?

This Big Red brand doesn't have the nose roller, I'm trying to find a picture of that nose roller again so that I can discussed it in an educated way, but I can't see one at the moment...
Aha. Ok here we go...
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This is an S&G 6631 Group 2M safe lock. It is advertised to have "false gates" and the "eccentric roller" on the nose. I have circled these in red.
The nose roller will make readings more difficult in drop in area, and the "false gates" will give indications to manipulator leading him/her to believe that there is a gate present when there is not. I don't think the false gates would be a good idea on a safe lock without a roller since it could cause a sticking point which would indicate to a manipulator that it's a false gate. In my opinion, adding an eccentric roller to the Big Red 2M would be a mistake since it would increase the width of the nose making readings easier, not harder. On the S&G which does not have the extra fence lifting arm, it makes sense. So these companies have gone different directions with their manipulation resistance. LaGard I believe has also gone the route of using an extra spring loaded arm to hold the fence up like the Big Red 2M
I shudder to think that there are people out there that could pop open a manipulation resistant lock... I'll try and convince the safe shop to loan me one for a little trial run when I am done with my S&G.
-LC

Re: Safe locks: Group 2 vs. Group 2M

PostPosted: Fri Apr 12, 2013 1:01 pm
by Oldfast
Libertyclicks wrote:....I shudder to think that there are people out there that could pop open a manipulation resistant lock...

I hope to be one of those people! :spinning: lol. Really though, I look forward to spending time with higher security locks.

But this also brings to mind another point... manipulation resistant locks are underutilized.
Matt Blaze eludes to this in his paper "Safe Cracking for the Computer Scientist", saying:

"The vast majority of commercial safes use Group 2 (and sometimes even unrated) locks. Even apparently
formidable containers that might require significant effort to penetrate by force are often equipped
with locks that can be manipulated open with no evidence by anyone familiar with the procedure.
"
He goes on to say that...
"The relative rarity of mechanical locks designed to resist expert manipulation seems somewhat surprising,
especially given that the containers on which they are used are often quite secure against penetration by
experts. Group 1 locks are not substantially more expensive than their Group 2 counterparts, and certainly
would not represent a significant increase in the overall cost of a container.
"

This is precisely why I don't mind publicly revealing manipulation and don't feel I'm overstepping my bounds.
People NEED to realize that not all mechanical locks are created equal, and many of them are not nearly as
inpenetrable as they might think. And for a little more money, they can get a lock that is much more apt to
resist manipulation from the average person that may have learned on their own (like you and I).

Re: Safe locks: Group 2 vs. Group 2M

PostPosted: Sat Apr 13, 2013 5:47 pm
by Farmerfreak
Libertyclicks wrote:The nose roller will make readings more difficult in drop in area, and the "false gates" will give indications to manipulator leading him/her to believe that there is a gate present when there is not.

The false gates in the S&G is a mistake on S&G's behalf, as it makes manipulation much easier than it would have been without them!

Think about it for a second. Finding a gate (real or false) is difficult enough because of the roller. But with the false gates, you only need to concentrate on about a third of each wheel until you find a gate on each (again, real or fake). Once a gate has been found on each wheel, those gates can be used to find the rest of the gates with ease, even with the eccentric wheel. Once all the gates have been found it will be simple to progress through all possible combinations if it didn't open already..

I haven't manipulated many of them, or consistently, but the false gates have always helped me out. And they definitely hold up to the 2M rating.

Re: Safe locks: Group 2 vs. Group 2M

PostPosted: Sat Apr 13, 2013 6:03 pm
by Oldfast
Farmerfreak wrote:[....But with the false gates, you only need to concentrate on about a third of each wheel until you find a gate on each (again, real or fake). Once a gate has been found on each wheel, those gates can be used to find the rest of the gates with ease,....

So it can make manipulation quicker most of the time? Similar to the approach taken with a Mosler 302?
Granted, I've only READ about these locks at this point... so I'm kinda talkin' out my ass. lol

Re: Safe locks: Group 2 vs. Group 2M

PostPosted: Sat Apr 13, 2013 6:09 pm
by Farmerfreak
I haven't manipulated a Mosler 302, and I'm not sure that I would try.. There is a big difference between a couple false gates on an otherwise smooth wheel and a constant run of never ending false gates...

Re: Safe locks: Group 2 vs. Group 2M

PostPosted: Sat Apr 13, 2013 6:12 pm
by Oldfast
lol... well, I'll find out one of these days. I've been on the lookout for one for a bit now.
And I've let a couple pass by on ebay - price went up just a little too high for me.
Great thoughts though Farmer. Thank you for sharing them.