Jump to content
BrainDen.com - Brain Teasers
  • 0


araver
 Share

Question

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) 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) 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) 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 pretty much 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 at least half of the clues. 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

Edited by araver
Link to comment
Share on other sites

Recommended Posts

  • 0

I was pretty sure I'd get a lot of attempts / brute force tries this time. Maybe there are fewer Hackers since it's Thanksgiving week, idk. Only dawh and octopuppy have expressed interest in it.

Anyway, my independent Hacker thoughts on this (which I had before posting the challenge):

IDEA 1) If I can't figure out an exact pattern but it seems that the algorithm chooses a starting letter first then I can start brute-forcing for a specific command by trying my-current-algorithm-best-shot on the command shifted by one position, two positions, etc. The number of possibilities is small.

IDEA 2) If I cannot accurately predict a letter in password that corresponds to a letter in command (i.e. there is no global function/ transformation that can be seen), then one of the following may be true:

EITHER there is a global rule/idea that changes the function depending on all the command itself (e.g. no of vowels in command / no of distinct vowels etc.) - e.g. Game 3, Game 6.

OR there is a more local rule that changes the outcome/transformation of a letter depending on the context in which this letter (e.g. left/right neighbors) - e.g. Game 5.

I used IDEA 1 in Game 5 and it would have taken me 5 tries without Vineetrika's correct hint for the starting position.

Also used IDEA 2 successfully in Game 5 - I used partial reasoning to predict the transformations for a particular command (ABORT) without actually having the whole rule or grasping its underlying logic.

I would have expected (from IDEA1) that someone might take a shot/more shots with an IDEA2-algorithm. Even without understanding its logic fully.

Just sayin' :)

I think the reason nobody has taken a shot is that nobody has any kind of working guess about the shift pattern. Given 3 possible start positions and 3 possible shifts for each letter, that's still 3^6 possible codes for a 5 letter word, and I for one can still find no way to narrow it further than that. But my guess is it comes down to local context...

Link to comment
Share on other sites

  • 0

Ah, north and south. I reckon you've been holding these back for a reason. I request South Dakota and North Carolina!

Edit: whoops, just noticed you already gave us one of those :blush:

No particular reason. But I make a point in avoiding north/south pairs since they might contain a weakness I did not see.

Here's the last of the pairs:

NORTHCAROLINA

TICBSQNK

EDIT: I only got 6 states left. And I am indeed protecting one of them :D

Edited by araver
Link to comment
Share on other sites

  • 0

I'm onto you now

:ph34r:

By all means :D

Anyway, a late response to one of your thoughts before. As the rules state, the Evil Mastermind accepts max 1 guess / player between 2 consecutive rounds of firing. So a big enough coalition of players can practically brute-force in between rounds B)) (Assuming the Evil Mastermind is not trigger-happy, which I am not at the moment.)

Link to comment
Share on other sites

  • 0

Password accepted. System shutting down.

Awww, maaaan ... I knew those meddling kids will stop me from reaching a perfect score.

:thumbsup:

Did I save enough of the USA for it to be worth saving? :lol:

BTW, which clue did you think would be a dead giveaway? For me it was the north and south ones that did it.

Link to comment
Share on other sites

  • 0

Did I save enough of the USA for it to be worth saving? :lol:

BTW, which clue did you think would be a dead giveaway? For me it was the north and south ones that did it.

Well TEXAS, IOWA, HAWAII, ARIZONA, ARKANSAS are grateful :lol:. Just figured that I was counting ABORT so actually only 5 remaining :wacko:

Idk really. I thought ARKANSAS after KANSAS would be a give-away so I refrained from that. But I was counting on the North/South pairs to help in some way but as no one was requesting them, I played them earlier than the end. Guess I wanted to be stopped :lol:

So, care to explain this time? :D

Link to comment
Share on other sites

  • 0
I thought ARKANSAS after KANSAS would be a give-away so I refrained from that.
Of course! :duh: I really should think to request those things.

It's funny, once you realise what the algorithm is you always start kicking yourself for not seeing it earlier.

Like I was looking at stuff like Mississippi and Missouri, Tennessee and Pennsylvania, seeing half a pattern but not seeing enough of one that it works and doesn't get broken elsewhere. But the clues were there. When you can say letter n is a function of x, y and z, then working out the function isn't too difficult. It's knowing what x,y and z are that's the trick, that's what made this one quite a challenge.

So, care to explain this time? :D
Hell no! Keep 'em guessing :P
Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Answer this question...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

Loading...
 Share

  • Recently Browsing   0 members

    • No registered users viewing this page.
×
×
  • Create New...