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While you're still puzzling over the algorithm to ,&do=embed' frameborder='0' data-embedContent> here's a bit of fun that occurred to me while doing the same. Rather than the mean unsolvable algorithm I was threatening, this should be a piece of fluff which will no doubt be solved rather quickly. But it contains a couple of ideas which I thought were quite cute, so I couldn't resist doing it.

One player plays the Evil Mastermind (that's me) who nukes the states of the USA 3 at a time, the other players play Hackers who seek to stop the Evil Mastermind. The Evil Mastermind plays by posting commands which activate missile strikes. Each command has a unique password, which is derived from the command by a hashing algorithm. The Evil Mastermind devises a different algorithm at the start of each game, and posts the passwords along with the commands. The Hackers will see the commands and passwords and from this they should try to deduce the hashing algorithm. The Hacker who does this first, and correctly figures out the password to the command "ABORT", stops the Evil Mastermind and wins the game. Anyone can join in at any time as a Hacker.

Now hashing algorithms can be exceedingly difficult to crack, but there are restrictions placed on the kind of algorithm that the Evil Mastermind can use:

1) What it is

The Evil Mastermind must be able to derive an alphanumeric password of fixed length from any word (password length 8 characters or less, you choose). It doesn't have to be a cipher in the sense that it can be decrypted to the original word, indeed the fixed length makes that impossible.

2) Simplicity

You must be able to do it in your head, with no external aids, in 40 seconds or less. You may look at the word you are hashing but you should not have to look at the previous letters of the password, since real-life passwords are generally shown as ***** as you type (although you may use previous letters as far as your memory can handle it). It's up to you to ensure that you can do all this. A really classy algorithm is one which fulfils this condition better (quick and easy to perform, in other words).

3) No memory feats

Although it is quite possible to hold an alphabetic substitution table in your head, and apply it quickly, I'll rule this out because in conjunction with other techniques it's too difficult to crack. Any technique that requires a large amount of information to be memorised in advance is not allowed. Caesar ciphers with a large shift may fall into that category.

4) Consistency

This is a matter of good sportsmanship. For example, since "ABORT" is the target word, you can't have a rule that comes into play only when the sequence "BOR" occurs. All rules should be general enough that they come into play in either one third of the clues posted at any given time, or 10 clues posted. The algorithm should not be geared toward the specific commands used in this game, but should work on any word.

Commands

There are 51 commands, these being the names of US states (used by the Evil Mastermind to nuke another state), plus the word "ABORT" (used by hackers to stop the Evil Mastermind).

Commands and passwords are all uppercase.

ABORT

ALABAMA

ALASKA

ARIZONA

ARKANSAS

CALIFORNIA

COLORADO

CONNECTICUT

DELAWARE

FLORIDA

GEORGIA

HAWAII

IDAHO

ILLINOIS

INDIANA

IOWA

KANSAS

KENTUCKY

LOUISIANA

MAINE

MARYLAND

MASSACHUSETTS

MICHIGAN

MINNESOTA

MISSISSIPPI

MISSOURI

MONTANA

NEBRASKA

NEVADA

NEWHAMPSHIRE

NEWJERSEY

NEWMEXICO

NEWYORK

NORTHCAROLINA

NORTHDAKOTA

OHIO

OKLAHOMA

OREGON

PENNSYLVANIA

RHODEISLAND

SOUTHCAROLINA

SOUTHDAKOTA

TENNESSEE

TEXAS

UTAH

VERMONT

VIRGINIA

WASHINGTON

WESTVIRGINIA

WISCONSIN

WYOMING

Game Play

The Evil Mastermind posts 3 commands at a time, with their passwords. The interval for doing this is undefined, no point in imposing restrictions. The Evil Mastermind chooses the commands, but should generally do requests as soon as possible.

Each Hacker may make one guess at the password for "ABORT" each time the Evil Mastermind posts commands. If someone makes multiple guesses in between clues, only the first one counts, but if they make a mistake and correct it, the Evil Mastermind can accept the correction.

There is no need for spoilers when guessing the password, although please use spoilers if you reveal the algorithm.

The first one to get the password for "ABORT" wins.

P.S. Alternatively if you've cracked the algorithm you can just use it to blow up more states if you're that way inclined (**per original Evil Mastermind's rules!)

- Host: octopuppy - Winner: fabpig

- Host: octopuppy - Winner: araver

- Host: araver - Winner: octopuppy

- Host: dawh - Winner: octopuppy

- Host: octopuppy - Winner: Vineetrika / araver,

- Host: Vineetrika - Winner: octopuppy

- Host araver - Winner: octopuppy

Update

49 states down, only 1 to go! Last chance to stop me going the distance...

Here are the clues so far:

ALABAMA

EOEDBQCB

ALASKA

EOEWMBDM

ARKANSAS

DVMBQVEW

CALIFORNIA

FEOLJSTO

COLORADO

DPNQSDEP

CONNECTICUT

EQOQGEXM

DELAWARE

GGPCZETH

FLORIDA

JORVMGEH

GEORGIA

KFPUKMCH

HAWAII

KEXDLLLC

IDAHO

JFBKRLED

ILLINOIS

JNPMPQKU

INDIANA

LRGLEPBJ

IOWA

LRYBJPAC

KANSAS

NEPUBTNE

KENTUCKY

OFQUVDNC

LOUISIANA

MPVJTJDR

MAINE

NDLRFQCK

MARYLAND

PETZNBQE

MASSACHUSETTS

QCUUBDKX

MICHIGAN

OKEIJJEP

MINNESOTA

OKOQGUQX

MISSISSIPPI

QMWWMWWM

MISSOURI

QMWWSYTK

MONTANA

OQOVBQEN

NEBRASKA

RFEVCULD

NEVADA

RFXBFBQG

NEWHAMPSHIRE

PHYIDOTW

NEWJERSEY

RFANFUVG

NEWMEXICO

QGZOHYJD

NEWYORK

RFAAQSNR

NORTHCAROLINA

RSTXJEBU

NORTHDAKOTA

RSTXJHCL

OHIO

PKLRRLMS

OKLAHOMA

ROOEJQPE

OREGON

RVFJRRST

PENNSYLVANIA

QIPOTBMX

RHODEISLAND

SKREIMWO

SOUTHCAROLINA

VRXUKFET

SOUTHDAKOTA

VRXUKEDO

TENNESSEE

WGOQGUUH

TEXAS

VHYDVUIA

UTAH

XUDLYWEJ

VERMONT

ZFUOQOVZ

VIRGINIA

WJUKMPKB

WASHINGTON

YBTKLRIX

WESTVIRGINIA

YHVUXKSJ

WISCONSIN

YKUEQOTJ

WYOMING

YZPQMPHA

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Posted · Report post

Coming clean with what I have so far ... some thoughts of cryptanalysis.

Can be read independently of the last code you're referring too (no spoiler for that in here).

My current hypothesis is that the first character is shifted +f1(command) than the first character in the command. where f1(command)=1,2,3 or 4.

Searching for a function that predicts function f1 has yielded so far the following thoughts:

- (Sure) first three characters in command are not enough to determine a first character in password (counter-examples: NEWMEXICO,NEWYORK, NEWHAMPSHIRE)

- (Sure) last character in command does seem to play a role (e.g. NEVADA, NEBRASKA start the same)

- (Sure 99%- Occam's Razor) second character in command does not seem to play a role (e.g. NEVADA, NEBRASKA, NORTH* start the same, despite the change in second character)

So, I'm pretty sure (for a while now) that f1 depends on first and last character. However, I did not find a simple f1 such that:

f1(A,A)=4

f1(A,F)=4

f1(A,G)=4

f1(A,N)=4

f1(A,I)=3

f1(A,M)=2

and so forth

It also seems commutative (f1(O,N)=f1(N,O)=3).

On the other side(s):

- normal crib finding and matching did not succeed (as they usually do if the same type of function is used for each letter in password).

- predicting f1(T,A) is not trivial without a strong notion of what f1 is so there's no simple brute-force even for the first character.

- no shift (start point choosing) appears to be in play, neither visible in how the password looks (sure of that), neither in how the password is computed (almost sure)

- all the differences are 1,2,3,4 which suggest either modulo 4 or bitwise operations modulo 2 (none satisfactory so far).

- either order does play a role OR the rounds of the function accumulate e.g. crib KANSAS in ARKANSAS yields different outcomes, yet the first-order delta sequence between the outcomes is -1 2 0 1 0 in KANSAS and 1 -2 0 -1 0 in ARKANSAS which suggest a sign-change

And that's about all I have ATM.

Nice to see the wheels turning. I bet you'll get it soon, or someone else will now you've posted that. :D
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Posted · Report post

Spinning it out now, 2 at a time. Only 6 left! Can I be stopped?

COLORADO

DPNQSDEP

NEWJERSEY

RFANFUVG

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Posted · Report post

SOUTHDAKOTA

VRXUKEDO

WYOMING

YZPQMPHA

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Posted · Report post

This is it folks, last chance!

IDAHO

JFBKRLED

TEXAS

VHYDVUIA

I can almost taste the victory...

post-4017-097337900 1291154665.gif

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Posted · Report post

wait, wait. see you there with your finger on the trigger and know you're supposed to be evil and all (as further evidenced by your masterminding this twisted plot) but if you have to blow us all up, maybe you could see it in your heart to give a little time before further smiting us with your algorithm...

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wait, wait. see you there with your finger on the trigger and know you're supposed to be evil and all (as further evidenced by your masterminding this twisted plot) but if you have to blow us all up, maybe you could see it in your heart to give a little time before further smiting us with your algorithm...
3 days and 48 states into this and now you want some time?

Well, all right then.

I'll just blow up half of what's left.

OKLAHOMA

ROOEJQPE

You've still got Arizona, but not for long :D

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Posted · Report post

is it EDQSVBER ?

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Posted · Report post

Now that I understand the logic for first letter, the code for ABORT is

BERVWEDQ

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Posted · Report post

Now that I understand the logic for first letter, the code for ABORT is

BERVWEDQ

Password accepted, system shutting down

Curses, foiled again! I'll get you next time, Arizona!

Well played, Vineetrika.

But what really surprises me is:

is it EDQSVBER ?
...which has everything right but the first letter. And I thought the first letter would be the first thing that anyone would figure out. :D
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I started off with analyzing the logic for the first letter but I got nowhere. Then I used Araver's clue (first and last letter combination has the same starting letter) to verify this for 2 letters in the middle of the word. That is when I saw a pattern. Once I got the pattern for the remaining letters, I started analyzing the logic for the first letter and it came to me quite easily.

This puzzle is very good and I enjoyed solving every bit of it.

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Posted · Report post

I started off with analyzing the logic for the first letter but I got nowhere. Then I used Araver's clue (first and last letter combination has the same starting letter) to verify this for 2 letters in the middle of the word. That is when I saw a pattern. Once I got the pattern for the remaining letters, I started analyzing the logic for the first letter and it came to me quite easily.

This puzzle is very good and I enjoyed solving every bit of it.

Congratulations :thumbsup:

I think you can discover the previous algorithm as well.

On an unrelated note, I guess you like octopuppy's rule of not disclosing the algorithm? :P

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On an unrelated note, I guess you like octopuppy's rule of not disclosing the algorithm? :P
It's not a rule, I just think it's nicer that way. There's only one truly satisfying way to find these things out, which is to solve it yourself.:D
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Posted · Report post

OK, so any hosts for CtC 9?

Octopuppy, do you wish to play the mean-algorithm now?

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Posted · Report post

OK, so any hosts for CtC 9?

Octopuppy, do you wish to play the mean-algorithm now?

I've been taking a few days off. Next time!
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