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  #1  
Old 09-10-2003, 10:41 PM
Blown & Injected Blown & Injected is offline
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Code Busters: Guess my PIN

The ATM card that I had (note Mods I no longer have this account so there is no risk here) on my business account was not used much so I wrote the PIN on the card in an encryption.

I'll add that it is a four digit number.

The number I wrote on the card is:

49236913293574598

I know that a PIN is not to be written on the card, but I did not really write the number on the card and do not believe that anybody could figure it out. Since the group here has more KSA's than the average thug, I thought it would be interesting to put my code to the test.

There is a factual answer to this and I will post it after the TMs have had a crack at it.
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  #2  
Old 09-10-2003, 10:51 PM
Cabbage Cabbage is offline
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What the hell:

0168?
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...ebius sig. This is a moebius sig. This is a mo...
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  #3  
Old 09-10-2003, 10:51 PM
Nobody's Fool Nobody's Fool is offline
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2138
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  #4  
Old 09-10-2003, 10:59 PM
Taran Taran is offline
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There is no solution that's better than random guessing. The problem is, your algorithm is private, so giving us your number doesn't really give us any information.

For example, let's say that I tell you that I've encrypted my 4-digit PIN, and the result is 2222. This number could be the product of any number of algorithms:

PIN#+1
PIN#-1
PIN#*2
(PIN#*13 mod 11)^4

...well ok, not that last one. But do you see why we don't have enough info to solve the problem?

All that said, if you put a gun to my head I'd choose 4627
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  #5  
Old 09-10-2003, 11:05 PM
Q.E.D. Q.E.D. is offline
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  #6  
Old 09-10-2003, 11:32 PM
DrMatrix DrMatrix is offline
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Is it 0000? No?
0001? No?
0002? No?
How about 0003? No?
How many tries do I get? Am I close?
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  #7  
Old 09-10-2003, 11:35 PM
Peregrine Peregrine is offline
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I'll take 6178.
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  #8  
Old 09-10-2003, 11:47 PM
Joe Random Joe Random is offline
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My guesses are 2138 and 4625
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  #9  
Old 09-10-2003, 11:48 PM
Joe Random Joe Random is offline
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Quote:
Originally posted by Joe Random
My guesses are 2138 and 4625
After posting, I see that Nobody's Fool went with 2138, so I'll go with 4625.
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  #10  
Old 09-10-2003, 11:54 PM
commasense commasense is offline
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1234?
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  #11  
Old 09-11-2003, 12:13 AM
Deathstatic Deathstatic is offline
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I see Nobody's Fool's reasoning that each number comes after each 9... so my guess opposite of his would be 4625.

Then again, that is boring... if you take each number and multiply it by the next number all of them beautifully go into 3 except for 5745, which is all together.

I have come up with all sorts of crazy schemes on figuring this one out. SO in answer to your question... I have no idea and I hate you. I wish I never would have found this thread because I have actually fallen down stairs marvelling at Fibonacci numbers. It was an excellent number theory class....

maybe 2140? MAKE IT GO AWAY!! TELL ME THE ANSWER!
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  #12  
Old 09-11-2003, 12:17 AM
Askance Askance is offline
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This is just a kudos for all posters so far for not saying "PIN number". Thank you.
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  #13  
Old 09-11-2003, 12:21 AM
Deathstatic Deathstatic is offline
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rather... are divisible by 3. 5745!!
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  #14  
Old 09-11-2003, 12:23 AM
Beryl_Mooncalf Beryl_Mooncalf is offline
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  #15  
Old 09-11-2003, 12:32 AM
Deathstatic Deathstatic is offline
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No, no... 1954

muahahahaahah.... help me
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  #16  
Old 09-11-2003, 12:48 AM
Nanoda Nanoda is offline
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Since your algorithm is not immediately obvious, finding a random set of numbers generated from a random set of other numbers is rather impossible.

OTOH, my friend and I had nothing better to do for 10 minutes, so:

After each 9: 2138
Before each 9: 4625
Using first 4 digits as index: 3292
Using first 4 digits as index into next 13: 3791
Use current digit as look-ahead value for next digit: 4634

And that's all the time I'm wasting on this.
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  #17  
Old 09-11-2003, 12:50 AM
hajario hajario is offline
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6752, I think.

This really should go in IMHO because it is more of a puzzle and you know the answer.

Haj
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  #18  
Old 09-11-2003, 01:02 AM
trabi trabi is offline
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6178 (The only numbers that aren't repeated.)
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  #19  
Old 09-11-2003, 01:02 AM
Joe Random Joe Random is offline
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Here's another guess (if multiple guesses are allowed). Since my last one was based on a simple algorithm, I decided to try something more complex.

The sequence 49236913293574598 is 17 digits long, and 17 is a prime number.

The number sequence can also be broken into four blocks, each of which also contains a prime number of digits (representing the first four primes, by the way).

49 236 91329 3574598

Notice that there are four groups: One for each digit of the PIN. Anyone with a basic understanding of prime numbers could reach this point with with no need for fancy calculations. So my next part will be just as simple. I'm going to add the digits in each block, and keep adding until I get a single digit. So:

4 + 9 = 13
1 + 3 = 4

2 + 3 + 6 = 11
1 + 1 = 2

9 + 1 + 3 + 2 + 9 = 24
24 = 6

3 + 5 + 7 + 4 + 5 + 9 + 8 = 41
4 + 1 = 5

So you end up with a PIN of 4265.
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  #20  
Old 09-11-2003, 01:07 AM
trabi trabi is offline
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Oops, Peregrine already thought of that.
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  #21  
Old 09-11-2003, 02:48 AM
DrMatrix DrMatrix is offline
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0004? No?
0005? No?
0006? No?
I'm sure my algorithm will get it eventually.
Quote:
Originally posted by hajario
6752, I think.

This really should go in IMHO because it is more of a puzzle and you know the answer.

Haj
Or MPSIMS.

Off to MPSIMS.

DrMatrix - GQ Moderator
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  #22  
Old 09-11-2003, 02:54 AM
green_bladder green_bladder is offline
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  #23  
Old 09-11-2003, 03:04 AM
SoulSearching SoulSearching is offline
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  #24  
Old 09-11-2003, 03:08 AM
Bryan Ekers Bryan Ekers is offline
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This is all a red herring.

His PIN is obviously "bosco".
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  #25  
Old 09-11-2003, 04:55 AM
j_sum1 j_sum1 is offline
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8954. It's obvious really. You just start reading it backwards.

What do I win?
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  #26  
Old 09-11-2003, 05:04 AM
Fern Forest Fern Forest is offline
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  #27  
Old 09-11-2003, 05:13 AM
indecisive1 indecisive1 is offline
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or 9854. the 4 at beging being sort of a key, 4 sets of 4 numbers that mean nothing at all.
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  #28  
Old 09-11-2003, 05:20 AM
indecisive1 indecisive1 is offline
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rats! I mean 4589 or course.
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  #29  
Old 09-11-2003, 06:06 AM
green_bladder green_bladder is offline
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I bet it'll turn out to be the most obvious combo: 4923 - the first four digits.
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  #30  
Old 09-11-2003, 07:20 AM
merge merge is offline
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4634
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  #31  
Old 09-11-2003, 07:38 AM
Bongmaster Bongmaster is offline
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redrum?
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  #32  
Old 09-11-2003, 08:17 AM
micco micco is offline
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I'm not going to bother a guess, but I'll take the opportunity to point to a recent interview with Bruce Schneier. Schneier is a crypto guru who has written several books on the subject and designed a couple of world-class algorithms. He points out that he keeps his computer passwords written on a slip of paper in his wallet. This is not because computer security is bad or he doesn't trust encryption, but because his wallet is full of other valuable things already and he has a lot of experience and instinct keeping it safe. Encryption is cool, but people are the weak link.

If I want your PIN, I'll beat it out of you.
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  #33  
Old 09-11-2003, 08:35 AM
Qazzz Qazzz is offline
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Who we really need is Marilyn vos Savant, who puts her record-breaking IQ to work solving important puzzles just like this one!
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  #34  
Old 09-11-2003, 10:20 AM
Blown & Injected Blown & Injected is offline
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Deathstatic, LOL, please don't hate me too much here is some help

I do not know much about this type of thing but I have always been amazed at the ability of hackers to crack into systems that seem to require a password.

What I did was to insert numbers that are to be disregarded - 9, and disregard the first and last numbers. The sum of two adjoining numbers equals one of the numbers in the PIN, these numbers are separated by a random number to be disregarded.

Thanks for playing and giving me some idea on how this type of thing works.
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  #35  
Old 09-11-2003, 01:36 PM
isthatsowrong? isthatsowrong? is offline
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So the answer is 42, then?
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  #36  
Old 09-11-2003, 01:53 PM
isthatsowrong? isthatsowrong? is offline
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Eleventeen? Thirty-twelve?

It seems that your scheme might be harder to remember than the PIN itself.
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  #37  
Old 09-11-2003, 05:18 PM
Nobody's Fool Nobody's Fool is offline
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Quote:
Originally posted by Deathstatic
I see Nobody's Fool's reasoning that each number comes after each 9... so my guess opposite of his would be 4625.

Her's
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  #38  
Old 09-11-2003, 07:53 PM
terd_ferguson terd_ferguson is offline
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9589
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  #39  
Old 09-11-2003, 08:20 PM
wakimika wakimika is offline
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9459
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