How many keys for Kryptonite?

Quoted message said:

I have a Kryptonite Kryptolok (new, with the flat key - not the old
bic-breakable type). This is a really nerdy question, but does anyone
know how many keys there are for these? It would appear very easy for
someone to have the same key as me, give that there are (on mine) only
3 notches on the key, each with only 3 or 4 possible shapes. The flip
side of the key is always identical, so that side provides no extra
permutations. This would make for only 27 or 64 keys *total*. Not
very secure!

Just curious..

The keys on many commercial products are more for show than for
protection. I haven't looked at the Kryptonite U locks, but I did
inspect their combination lock cables, which were easily opened with a
screwdriver.

--
Bob Wheeler --- http://www.bobwheeler.com/
ECHIP, Inc. ---
Randomness comes in bunches.

Quoted message said:

It would appear very easy for
someone to have the same key as me, give that there are (on mine) only
3 notches on the key, each with only 3 or 4 possible shapes. The flip
side of the key is always identical, so that side provides no extra
permutations. This would make for only 27 or 64 keys *total*. Not
very secure!

People who steal bikes don't carry around a bunch of keys.

Rich said:

People who steal bikes don't carry around a bunch of keys.

True, true.. I'm not at all concerned - I'm just a little surprised
that there would be so few keys for ALL of the Krypto locks in the
world. 27. With that few, you stand a *good* chance of having the
keys to your neighbor's bike lock.

Quoted message said:

True, true.. I'm not at all concerned - I'm just a little surprised
that there would be so few keys for ALL of the Krypto locks in the
world. 27. With that few, you stand a *good* chance of having the
keys to your neighbor's bike lock.

I'd say most people don't have bike locks, as most people don't have a
bike they actually use. And since there are a variety of different
types of locks, even if your neighbor DOES have a lock, he or she
probably doens't have a Krypto lock. And in the unlikey event your
neighbor has a bike, and a bike lock, and it's a Krypto lock, the odds
are still only 1 in 27. Not very good odds.

So, I'm willing to bet you do not have the keys to your neighbor's bike.

Rich

Rich said:

Quoted message said:

True, true.. I'm not at all concerned - I'm just a little surprised
that there would be so few keys for ALL of the Krypto locks in the
world. 27. With that few, you stand a *good* chance of having the
keys to your neighbor's bike lock.

I'd say most people don't have bike locks, as most people don't have a
bike they actually use. And since there are a variety of different
types of locks, even if your neighbor DOES have a lock, he or she
probably doens't have a Krypto lock. And in the unlikey event your
neighbor has a bike, and a bike lock, and it's a Krypto lock, the odds
are still only 1 in 27. Not very good odds.

So, I'm willing to bet you do not have the keys to your neighbor's bike.

Rich

Well I don't know about the keys to the neighbour's bike but when I was
young my family's car keys fit the neighours (Many years ago).

Quoted message said:

I have a Kryptonite Kryptolok (new, with the flat key - not the old
bic-breakable type). This is a really nerdy question, but does anyone
know how many keys there are for these? It would appear very easy for
someone to have the same key as me, give that there are (on mine) only
3 notches on the key, each with only 3 or 4 possible shapes. The flip
side of the key is always identical, so that side provides no extra
permutations. This would make for only 27 or 64 keys *total*. Not
very secure!

Just curious..

Between my two Kyptonites I'm counting five slots and up to five angles
per slot (looks like every 15 degrees angle, and they omit 90 degrees
because it might not turn well in the lock).

That gives me 5 ^ 5 = 3125 combinations instead 3 ^ 3 = 27. If they
don't omit 90 degrees then I'm in even better shape: 6 ^ 5 = 7776.

Possibly your key just has a bland looking shape and the other two slots
are actually valid combinations?

-Collin

"Collin O'Neill" wrote: Between my two Kyptonites I'm counting five slots
and up to five angles per slot (looks like every 15 degrees angle, and they
omit 90 degrees because it might not turn well in the lock). (clip)
^^^^^^^^^^^^^^^
I have done minor locksmithing, but I can't figure oput what you mean. The
OP specifically said he was talking about the new flat-key Kryptonite locks.
What are the "angles" you are talking about? If you are talking about the
cylindrical keyed locks, then what are the "slots" you refer to?

Collin O'Neill said:

Between my two Kyptonites I'm counting five slots and up to five angles
per slot

Yeah, you are correct actually. I checked out someone else's key for
the same model lock, and there are 5 slots. My key just looked like
only 3 because adjacent slots have the same angle making it look rather
simple.

Never mind!

Quoted message said:

I have a Kryptonite Kryptolok (new, with the flat key - not the old
bic-breakable type). This is a really nerdy question, but does anyone
know how many keys there are for these? It would appear very easy for
someone to have the same key as me, give that there are (on mine) only
3 notches on the key, each with only 3 or 4 possible shapes. The flip
side of the key is always identical, so that side provides no extra
permutations. This would make for only 27 or 64 keys *total*. Not
very secure!

There are probably more positions then you realise, notches are
typically in a V position, a pin and tumbler based lock could have a pin
anywhere in one of those V shaped spots, and not just the bottom. Have
a look at http://home.howstuffworks.com/lock.htm and run the little
animation, to see how it all works.

Often keys have numbers stamped on them, so you can order new keys, how
many digits are the number? Most car keys are 4 digits, which means
that for every 10,000 cars made, 1 car has that same key number, so if
that manufactuer makes 1,000,000 cars in a year (like GM does), 100 of
those have that same key number...... Therefore there is 1:10000 chance
that your key can open another car.

W

Leo Lichtman said:

"Collin O'Neill" wrote: Between my two Kyptonites I'm counting five slots
and up to five angles per slot (looks like every 15 degrees angle, and they
omit 90 degrees because it might not turn well in the lock). (clip)
^^^^^^^^^^^^^^^
I have done minor locksmithing, but I can't figure oput what you mean. The
OP specifically said he was talking about the new flat-key Kryptonite locks.
What are the "angles" you are talking about? If you are talking about the
cylindrical keyed locks, then what are the "slots" you refer to?

Please excuse the childish illustration. Hopefully the picture will make
it clearer.

http://mailman.elitechicago.com/~collin/kryptonitekey.png

-Collin

"Collin O'Neill" wrote: Please excuse the childish illustration. Hopefully
the picture will make it clearer.
^^^^^^^^^^^^^^^
The illustration is clear enough to serve the purpose, so there is nothing
to apologize for. However, I think you are misenterpreting what you see
when you look at the key (unless Krypronite has come up withan entirely new
system.) You are correct that the key has a number of positions, equally
spaced, where the notches are located. Most locks have five positions.
Some cheap locks have four. The coding is done by filing V shaped notches
along the key blank to various DEPTHS--not angles. Since the notches are
closely spaced, they usually overlap at the top, so you end up seeing a wavy
key edge. This may look to you like various angles. The point is, each
notch is matched to a pin tumbler whose length matches the depth of the
notch. When the correct key is inserted, each tumbler falls to a depth
which lines it up with the surface of the cylinder, and the key will turn.

It is difficult to look at an individual key, and, by eye, determine how
many discrete depths are used in the coding system. It doesn't take much to
block the rotation of a key, so it is possible that the lock is more secure
than it looks to the naked eye.

Leo Lichtman said:

"Collin O'Neill" wrote: Please excuse the childish illustration.
Hopefully the picture will make it clearer. ^^^^^^^^^^^^^^^ The
illustration is clear enough to serve the purpose, so there is
nothing to apologize for. However, I think you are misenterpreting
what you see when you look at the key (unless Krypronite has come up
withan entirely new system.) You are correct that the key has a
number of positions, equally spaced, where the notches are located.
Most locks have five positions. Some cheap locks have four. The
coding is done by filing V shaped notches along the key blank to
various DEPTHS--not angles. Since the notches are closely spaced,
they usually overlap at the top, so you end up seeing a wavy key
edge.

I see what you mean, but I really think Kryptonite's got a slight twist
on your description above. It wouldn't be difficult to
machine either way. In your description, the grinder is pressed
vertically into the blank. In the keys I'm looking at right now the same
grinder would simply be rotated into the blank.

Quoted message said:

This may look to you like various angles. The point is, each
notch is matched to a pin tumbler whose length matches the depth of
the notch. When the correct key is inserted, each tumbler falls to a
depth which lines it up with the surface of the cylinder, and the key
will turn.

It is difficult to look at an individual key, and, by eye, determine
how many discrete depths are used in the coding system. It doesn't
take much to block the rotation of a key, so it is possible that the
lock is more secure than it looks to the naked eye.

Yes, it certainly looks like you could fit more. By comparison of the
two keys in my hand I would have a minimum of 3125 combinations, but of
course I could have more.

Quoted message said:

Well, I don't mean to be pedantic on what is aleady an esoteric (but
interesting topic). At least we've determined they keys have a lot of
combinations.

"Collin O'Neill" wrote: (clip) It wouldn't be difficult to machine either
way. In your description, the grinder is pressed vertically into the blank.
In the keys I'm looking at right now the same grinder would simply be
rotated into the blank.
^^^^^^^^^^^^^^
At least now we have isolated our difference. The problem I have with your
"rotation" idea is that, while it WILL make a key, I know of no
corresponding way to set up the lock cylinder to work with such a key. In
the classic system, locksmiths and lock manufacturers have bins full of pins
of various lengths. If the proper pins are dropped into the holes, the lock
can be matched to the key. Under the system you are describing, a pin
length would have to be determined by trigonometry, or some kind of CAD
program.
^^^^^^^^^^^^^
At least we've determined they keys have a lot of combinations.
^^^^^^^^^^^^^^
Agreed.

Rich said:

I'd say most people don't have bike locks, as most people don't have a
bike they actually use. And since there are a variety of different
types of locks, even if your neighbor DOES have a lock, he or she
probably doens't have a Krypto lock. And in the unlikey event your
neighbor has a bike, and a bike lock, and it's a Krypto lock, the odds
are still only 1 in 27. Not very good odds.

So, I'm willing to bet you do not have the keys to your neighbor's bike.

By comparison, around here about 50% of the population will have at least
one bike that is primarily secured with an Axa SL or Axa SL7/9 ring lock
(the other 50% or so being secured with other locks). The amount of
combinations on those is reasonably high, for obvious reasons.

Jasper