Creating a masterkey from a change key...

[mr_guy99493]

I just re-read the mit guide to lockpicking, and came up with this idea...

could someone verify that this would enable me to get a master key from a change key and lock that it opened.

1. get 6 or 7 blanks for the change key, and duplicate them, except for the depression where one pin would go, which would be left at its highest position,

2. slowly grind this part of the key away, testing on the lock, until it opened the lock. The heights duplicated from the change key should set most of the keys to the right height, but the gringed one should
give either the sheer height for the master or change key.

3. get my vernier calipers out and measure it, if the same as the change, keep grinding, otherwise this is the height for the master.

4. repeat the above process with the next pin.
5. when all is done, grind a new master from the measurements taken.

sounds doable to me...
what do you think?

(still contemplating buying a bench grinder and hacksaw blades, or shelling out for some premade picks.....)

mr_guy99493
aim in life: to become a "jack of all trades..... master of all trades."

[sivlogkart]

You handle here has just reformatted my brain.

KJ

[raimundo]

are ya sure that you didn't read matt blaze's paper on that technique in another lifetime?

[Chrispy]

Possibly....

A lot of key systems that use masterkeying are also using restricted key blanks, hence, find a nice lockie that will copy them and you might be in business....

Also, It depends on the amount of change keys (and therefore the amount of sheer lines), you could go through a lot of blanks....

I dunno... anyone else?

[hzatorsk]

Well... it's a heck of a lot of work... The results will really depend on the master key system used and your desire to work through the possibilities of more than one master pin and that each master may be higher or lower than the change.

You'll put yourself through all the various combinations of keys that may appear as master keys because they are different than the one you have. But you may just have other change keys that are miskeyed to one of the master pins or perhaps a subordinate master.

To know for sure... you'll have to try it throughout the keyspace... and that means you either own the locks in question (and therefore already have the master) or are testing keys in other peoples locks (illegal).

Myself, if I had this much exposure to the lock. I'd simply disassemble it and get the pinning right out of the lock. Many times, the previous locksmith will have conveniently color coded the master pins for you. THIS method only takes ten minutes!!

[SFGOON]

Raimundo is right, there is a very famous academic paper by professor Blaze at the univeristyof pensylvaniam about this technique. He calls it "rights amplification" and you can doewload the pdf at www crypto.com

[mr_guy99493]

I just had a quick read over the paper,
its interesting that he points out that people must have thought of this before him, pointing out college students in particular, as i myself am a college student.

sometimes i wish i was born 100 years ago, so that i could make money off all my ideas, instead of just finding out that they have already been realised by someone else...

mr_guy99493
my goal in life: to become a "jack of all trades..... master of all trades"

[keysman]

I have done this several times and yes it does work, what you end up with is 3 or 4 keys that 1 is the top level master ( assumming you have a multiple level master system) you have to check all the locks in the system to be 100% shure which of those keys is actually the Highest level master. (GM or GGM)
What you will have is some sub masters that may work some locks.


hzatorsk ? Having a change key and trying to determine the master by decoding the pins will only tell you what it COULD be ( in multilevel master stsyems) Many systems use HIGHER-Lower cuts to prevent a change key from being filed down to a master. So just checking the bottom pins won't always work.

Good locksmith skill to have and be proficient at, you never know when a master key is unavailable, such as when a large office has been vacated
and the keys went with the previous owner.

[Chrispy]

Good locksmith skill to have and be proficient at, you never know when a master key is unavailable, such as when a large office has been vacated
and the keys went with the previous owner.

Wouldn't that be the time to re-pin all the locks and create a new system? You don't want the old tenants coming back and their old keys open all the doors of the new tenants office areas? Kind of a security flaw if you ask me.

[sivlogkart]

That sort of thing happens often. I knew someone who was very security aware, and moved into a new rented house. After about 6 months did a bit of gardening to find a key to the house under a big stone near the front door!

KJ

[hzatorsk]

hzatorsk ? Having a change key and trying to determine the master by decoding the pins will only tell you what it COULD be ( in multilevel master stsyems) Many systems use HIGHER-Lower cuts to prevent a change key from being filed down to a master. So just checking the bottom pins won't always work.

keysman, Agreed... I thought I made that point when I said:

...work through the possibilities of more than one master pin and that each master may be higher or lower than the change....

You'll put yourself through all the various combinations of keys that may appear as master keys because they are different than the one you have. But you may just have other change keys that are miskeyed to one of the master pins or perhaps a subordinate master.

I was hoping to present the idea of disassembling the lock would be a faster method of discovery that what he was trying to do with a file. But, the findings will be the same in the end.

z

[Ezer]

I was hoping to present the idea of disassembling the lock would be a faster method of discovery that what he was trying to do with a file. But, the findings will be the same in the end.

z

Actually on a video on LSS+, Matt Blaze uses his method to find the master key of a Schlage master key system using a Pak-A-Punch in 10 minutes and that's with stopping to explain the steps he's doing.