SJS wrote:
begin quoting Ralph Shumaker as of Mon, Aug 11, 2008 at 05:52:30PM -0700:
SJS wrote:
[snip]
To what tolerance? 30 degrees? 15 degrees? I'm not suprised that
thickness isn't a real factor.
Tolerance? First, I'll answer that I don't really know. But, new, I
would estimate about 10?. That being said, I don't know what the
rotation angle is supposed to be. I think it's 45?. If not, then it
wouldn't be much less. I'll take a look next time I'm next to the
machine I use.
So it's a rotate left, rotate right, or rotate-none?
Actually, yes.
Or even just a "rotate or not"? Is it really a single bit's worth
of information?
Each location has 10 depths and 3 angles for each depth. Because of
spacing limitations on the key itself, not all combinations are usable.
So out of 30 usable in position 1, you may have (just a guess) 25
available in each successive one, depending upon the varying spacing
concerns. Generally, Medeco has 6, 7, or 8 pin chambers. So, there are
many millions of possible combinations. If not for the spacing
limitations on the key, Medeco would have (10*3)^[678] (following
standard mathematical notation except for "[678]" which I used to
represent regex, i.e. 6 OR 7 OR 8.
But regarding the 3 angles each, that seems to me like a bit and a half, no?
[snip]
Yeah, you would *think* that, but twisting is not the biggest threat to
a plastic or nylon key in an ignition. There are a few things in most
ignitions that will clamp down too hard on a plastic or nylon key but
which don't affect a metal key all that much. You probably wouldn't
even be able to push a plastic or nylon key IN through pinch rollers (on
Volvo or VW or somesuch), and even if you do manage to get it in, you
*aint* gettin it out. Most plastic keys that I have to dig out require
me to move a strong mechanism out of the way. What makes this more
difficult is that the tools move the mechanism out of the way, but then
the tools are in the way. A sure-fire exercise in frustration at times,
even if you *do* have my level of patience. But, over time, I've gained
a decent level of dexterity in it.
Ah, that's a far cry from my pontiac, then. My keys would fall out
of the ignition while the car was running.
A brand new code cut key probably won't fall out (until the points wear
off again).
Note to self - don't use nylon keys in a european car...
Even domestic cars can clamp down on nylon keys.
I quote from the article:
"Once the plastic key is inside the cylinder and lifts the pins, it's
not actually strong enough to turn the cylinder, so the researchers
insert a small turning wrench to turn the cylinder and open the lock."
Well, turning is not what I was thinking would be the most likely thing
to break it off inside, altho that could do it easily enough. A turning
wrench would help with turning, but not removal.
Ah! This is the pinch-roller and other tricks, yes?
Well, Medeco has no pinch-rollers or other such things that I know of.
It shares in common with most locks several chambers of spring loaded
pins pushing into the low spots of the key. They don't like going
uphill, especially on soft plastic. On a bad hair day, the plastic is
more likely to tear than to come out peacefully. And if the keyhole
isn't positioned in the right spot when you pull, a metal key just
refuses to come out until you hit the right spot. A plastic key is
likely to allow you to pull its head off, especially if there is even
the tiniest crack in the plastic.
If a key isn't cut right, all kinds of problems could result. Although
it is rare, one kind of cut fault can stop a key from going in. Another
cut fault will allow the key to go in just fine, but stop it cold from
coming back out. If I wanted to screw you over, I could cut such a key
and stick it into your lock. It doesn't damage the lock, but it would
make it almost as difficult to unlock.
Epoxy is cheaper, faster, and requires less work. :)
True, but my point was that epoxy is vandalism. My special cut key is
not. It was an accident. *YEAH!!!* That's it!!! It was a mistake in the
cutting process. ;)
But my point about the plastic key is that forces inside the lock
attempt to hold the key in place and could be strong enough to prevent
you from removing a plastic key without ripping it in twain.
Those forces would also wear a metal key out faster, and reduce the
working lifetime of the lock. It's all a tradeoff.
SJS, journeyman locksmith, who knew?
[snip]
Part of the problem is that there's a desire to loan out keys to give
someone temporary access to a resource, and once someone has the key
under their control, the game seems to be up.
The problem here is that *seeing* a key is sufficient to break it.
This is true. If I am at your house and your keys are laying somewhere,
I don't need a camera. But I _would_ need to stare at one of them for a
few seconds.
A camera would be easier. :)
You sometimes have such a knack for stating the obvious! :)
And with cameras in almost every phone... probably less obtrusive than
you staring at my keys. And can be used from farther away.
I'm not so sure about that. I said a few seconds. 3 to 5 would likely be
sufficient without practice. With practice, perhaps about a second for
each key. Several infrequent glances would hardly be noticed. I could
even pretend interest in some item on the key ring, or even the ring
itself while scoping out the cut patterns of the keys.
On the other hand, I have more keys that no longer go to anything than
keys that go to something.... you've have to memorize a lot of keys.
Maybe, but how many 5 digit numbers can you memorize long enough to
write them down? With certain simple memory techniques, you could
memorize as many as a hundred fairly quickly. Kevin Trudeau memorized
all the phone numbers and names of the audience members by simply
hearing each one once at the beginning of the program. Without writing
any of them down, he remembered them all until after the program was
over. I've used the techniques, and I can attest that they are for real.
I just never practiced them enough to become proficient.
--
The way to get a maximum rate of ‘economic growth’ – assuming this to be
our aim – is to give maximum encouragement to production, employment,
saving, and investment. And the way to do this is to maintain a free
market and a sound currency. It is to encourage profits, which must in
turn encourage both investment and employment. It is to refrain from
oppressive taxation that siphons away the funds that would otherwise be
available for investment. It is to allow free wage rates that permit and
encourage full employment. It is to allow free interest rates, which
would tend to maximize saving and investment.
--Henry Hazlitt
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