Thursday, 21 May 2015

cipher - Crypto-wordsearch-gram: "You Are a Member of the Rebel Alliance, and a Traitor!". A cryptogram hidden within a wordsearch




  • You are a member of the Rebel Alliance.





  • You have been captured by the Empire and imprisoned.




  • In a stroke of sadistic brilliance, your guards have denied you all reading matter except "Uncle Vader's News for Younglings", an Empire propaganda publication which has an intended readership aged 5 to 8 years.




  • But unknown to the Empire, the Rebel Alliance has a secret sympathiser placed within the publication's editorial office.





  • The sympathiser has replaced the weekly wordsearch puzzle with one of the Rebel Alliance's own devising - and they're using it to get a message to you!




  • The puzzle is: find the secret message hidden in the wordsearch!




Wordsearch: Uncle Vader's News for Younglings


Words to find:


ALDERAAN

AMIDALA
ARMY
CHEWBACCA
CLONE
COUNT
CORUSCANT
COUNT
DAGOBAH
DARTH
DEATHSTAR

DROID
EWOKS
FORCE
GALAXY
HAN
JABBA
JEDI
PADME
SITH





  • Hint: The answer contains (but does not consist solely of) the word 'EWOKS'.




  • The introductory text is just for fun and does not contain any enciphered information. All the information you need is in the wordsearch itself and the 'words to find' list.




  • The answer is a series of Roman-alphabet characters. There are no spaces or punctuation. The words are separated by 'X' characters ('THISXISXANXEXAMPLE'). The puzzle is not case-sensitive and there are no roman numerals in it. All the words except for EWOKS are dictionary words.





  • No knowledge of Star Wars is necessary to solve this puzzle.




  • This is my first time doing one of these (possibly the first time anyone's ever done one of these) so please be patient if I've made any errors or typos.




  • This type of puzzle is called a Cryptogram (although this is quite an unusual one in that it is steganogophised into a wordsearch). A known section of plaintext ('EWOKS') is called a crib.




  • The message can be read by the prisoner in the cell without the need for a computer. You can feel free to use a computer to crack the code, but it's a pencil-and-paper cipher.





  • A couple of minor bugs have been found (thanks for bug reports!), neither of them should screw up the puzzle, although the first one might make it slightly harder. If many more bugs emerge then I might redraft. Probably best to consider this a beta release. ;)




    • Yes, you do need to find COUNT twice.




    • The 'HAN' in the top-left quadrant is the one that's there intentionally - that's the one you're intended to find. The 'HAN' in the bottom-right quadrant is there by accident and should be ignored.







  • Chatroom is now open: http://chat.stackexchange.com/rooms/18735/crypto-wordsearch-gram-you-are-a-member-of-the-rebel-alliance-and-a-traitor




The text of the puzzle is below:


HABLXNERCWNCTJQINOCY
MIMVDFJDKJRJOELPXUEX
VNRFENIPCTBSLIVATMNA

BRKDHLUADEMUCYMZYCOL
CRNJAORDMWEUJIEBTOLA
CKRJNVEMMOIRDBRXKUCG
ECROFNDELKVARIDEJNMH
MFAYFEAJTSLXFNHFYTAA
ORTNJDRURANJDUEHCCIB
MBSUFETLNRABBAJVCKMO
QFHJUVHGNAAREDLAMFBG
NJTFVHYTTMJDYNBGEYLA
BIAGRDHNLINDCWJTMMVD

YVEJUHAFYKMGEEHRCUNR
UNDENCIBFKEHLOAVTHSK
USYNSKTDNLCMDYNEFJHT
NJMUDGBJHUDIORDBRGNN
IMRRKLEDNTOUEMLLQDUU
NOUYNCGPKEINIFUTNURO
CMXIUNTDRMLSKYBGELPC



Clues (if you need them):




Big Clue: ignore the 'filler letters' which fill the spaces in between the words that you have to find. They could be any letters at all and it would make no difference to the puzzle.

Another Clue: the word 'Ewoks' in the wordsearch is not specifically related to the word 'Ewoks' in the plaintext. It would be possible to swap 'Ewoks' for a different word in the wordsearch, without changing the plaintext.

Clue 3: the order of the words in the 'list of words to find' is significant. If we jumbled up the order in which they are listed then the puzzle would be broken.

Clue 4: the start position of each word (in the grid) is significant.

Clue 5 (Monday): the orientation of each word (in the grid) is significant.

Totally-giving-it-away-now bonus clue: Those three things (word list order, start position of each word in the grid, orientation of each word in the grid) are all that matters. Between them they carry all the information about the plaintext.

Tuesday clue:
- All the following directions mean the same thing as each other: N, NE, E, SE.
- All the following directions mean the same thing as each other: S, SW, W, NW.

Tuesday massive bonus clue:
Each word-to-find represents one character in the plaintext. It starts with:
ALDERAAN: e
AMIDALA: w
ARMY: o
CHEWBACCA: k
CLONE: s





Answer



The answer is:



EWOKS ATTACK AT DAWN



The explanation is:



As AE said, the only important information is the order, the grid positions and the direction of the words. I call directions S, SW, W, or NW direction 1, and the others direction 2.




From there we just apply the formula:



If (direction 1) then calculate (row number + 20) mod 26. Else (direction 2) just take the column number. Apply the usual number to letter mapping (1=A, 2=B, etc). Interpret Xs (24) as spaces.



So, for example:



ALDERAAN runs in direction 1 and starts in row 11. 11 + 20 = 31. 31 mod 26 is 5. E is the 5th letter of the alphabet. ARMY runs in direction 2 and starts on column 15. Letter 15 is O.





Additional info added by AE:



That's absolutely correct.


For our prisoner to begin deciphering, he just needs to:



Write the alphabet across the top of the wordsearch and then down the left-hand side, as I did when I was creating it: wordsearch solution (note extra row/column at top and left). Then if the word points up/right you take the letter from the top of the grid, if it points down/left then you take the letter from the left of the grid.



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