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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:
Spoiler for Hashing algorithm rules
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 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).
Spoiler for List of commands
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 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" for 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!)
