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On Fri, 20 Jun 2008 11:31:23 +0100, Invisible wrote:
>>> And apparently my key is a "master
>>> key" that opens several other doors as well. (Doesn't that mean all
>>> the locks are identical??)
>>
>> No. Why would you think that?
>
> Because any given key only opens locks of the exact same shape?
Go and find a copy of the MIT Guide to Lock Picking. Seriously. It
explains this and you learn a lot about the mechanics of mechanical locks
from reading it.
Jim
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On Fri, 20 Jun 2008 12:00:33 +0100, Invisible wrote:
> It's difficult to see how you'd make two
> unrelated shapes both have this property.
Two shearing points in the pins.
Jim
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Darren New wrote:
> Warp wrote:
>> I have difficult time bending my mind into resolving how exactly it is
>> done, but I can perfectly imagine there's a simple way. Ingenuous, but
>> simple.
>
> Math professor writes an equation on the board, and says "The proof is
> trivial. Wait, is it?" He wanders back to his office, returns in 20
> minutes to the classroom, and says "Yes, indeed, the proof is trivial."
>
Old but still gold :-)
John
--
I will be brief but not nearly so brief as Salvador Dali, who gave the
world's shortest speech. He said, "I will be so brief I am already
finished," then he sat down.
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On Tue, 24 Jun 2008 08:12:00 +0100, Doctor John <doc### [at] gmail com>
wrote:
>Darren New wrote:
>> Warp wrote:
>>> I have difficult time bending my mind into resolving how exactly it is
>>> done, but I can perfectly imagine there's a simple way. Ingenuous, but
>>> simple.
>>
>> Math professor writes an equation on the board, and says "The proof is
>> trivial. Wait, is it?" He wanders back to his office, returns in 20
>> minutes to the classroom, and says "Yes, indeed, the proof is trivial."
>>
>Old but still gold :-)
>
That happened in one of my high school maths classes (true). Now I
think the teacher just went for a fag. (Cigarette)
--
Regards
Stephen
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> For that matter, there are cool things you can do with cryptography and
> math that let you have similar relationships with passwords. Stuff like
> "this file can be decrypted by any three of the seven officers of the
> company, or by unanimous application of the keys of the department heads
> of the company. Oh, and we can invalidate any key without invalidating
> the others."
Sounds like BluRay encryption to me :-)
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> I suppose it's simply a question of cleverly allocating combinations
> of pin assignments to locks and keys. I can imagine at least one simple
> way of achieving a hierarchy of master keys with pin locks:
Our office keys have the normal jagged key cut for the pins in the lock, but
then they also have another "key" feature engraved on the side, like a
series of recesses drilled at certain points. Maybe some locks only work on
one set of features, or some on both, I don't know.
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Darren New wrote:
> I once spent 2 or 3 hours looking for my keys, because they were in the
> wrong pocket of the trousers hanging on the hook. I checked my pocket!
> They're not there!
Yeah, I've done this.
Also, if my pockets are too small to hold all my items, and I know I
don't need one of them, I leave it behind. I then spend the whole day
thinking I've lost something because my pockets are not the correct
weight. o_O
--
http://blog.orphi.me.uk/
http://www.zazzle.com/MathematicalOrchid*
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Phil Cook a écrit :
> And lo on Mon, 23 Jun 2008 13:19:07 +0100, Vincent Le Chevalier
> <gal### [at] libertyALLsurfSPAMfr> did spake, saying:
>
>> Invisible a écrit :
>>> Yeah, well, devise an unpickable lock and somebody will just rip the
>>> door off its hinges, or break in through a window or something. ;-)
>>> Weakest point and all that... All you really need is for the lock not
>>> to be the weakest part of the system.
>>>
>>
>> And do not lose your keys :-)
>>
>> It's all nice and well to have an unbreakable door and lock until you
>> have to destroy your own wall to go into your own house because the
>> keys were lost somehow...
>
> I think I'd try a window first ;-)
>
I was assuming that the windows were armoured in the same unbreakable
fashion as the door, of course :-p
--
Vincent
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Jim Henderson wrote:
>
> Go and find a copy of the MIT Guide to Lock Picking. Seriously. It
> explains this and you learn a lot about the mechanics of mechanical locks
> from reading it.
>
> Jim
Or just simply take one lock apart and check what it has eaten :).
Preferably a one that has master-key -functionality, then you'll
understand that also ;).
--
Eero "Aero" Ahonen
http://www.zbxt.net
aer### [at] removethiszbxtnetinvalid
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And lo on Tue, 24 Jun 2008 10:15:12 +0100, Invisible <voi### [at] devnull> did
spake, saying:
> Darren New wrote:
>
>> I once spent 2 or 3 hours looking for my keys, because they were in the
>> wrong pocket of the trousers hanging on the hook. I checked my pocket!
>> They're not there!
>
> Yeah, I've done this.
>
> Also, if my pockets are too small to hold all my items, and I know I
> don't need one of them, I leave it behind. I then spend the whole day
> thinking I've lost something because my pockets are not the correct
> weight. o_O
Heh had this yesterday, parked my car on the drive and got out to open the
garage door and fell into conversation with my neighbour. Put my hands in
my pockets and thought "Where are my car keys?". I've been doing the same
with my camera case it feels weird to go out without it now.
--
Phil Cook
--
I once tried to be apathetic, but I just couldn't be bothered
http://flipc.blogspot.com
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