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| $100 reward - The American ADFGVX Cipher (updated 7/10); aiming to forgo columnar transposition | |
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| Tweet Topic Started: Jun 22 2014, 01:58 AM (3,232 Views) | |
| a649b9e0 | Sep 15 2014, 12:42 PM Post #16 |
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Just registered
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I found the challenge set a little limiting, so I ran my own. Your worries about the key character showing are well founded. Let's for a moment assume that the headers are a known. Here are test runs encrypting each line of Alice in Wonderland and War and Peace:
These are a frequency analysis of the first digraph of the cipher texts. If we know the headers, we know AA is the 0, 0 position. Any guesses as to what the first letter of my key is? Also, we can start assembling a guess at the initial state of the alphabet in relation to the 0, 0 position. If we have plain text to the right handful of messages, it starts falling away like dominoes. Now, let's take the opposite assumption, that which the headers are unknown. We still can make a 1 to 1 association between this state's digraphs and the letters it encrypts. Also, our set of possible key letter digraphs only goes up to 6 (AA, DD, FF, GG, VV, XX) as we know that the x and y axes of the state array share the same quantity at the key letter. Edited by a649b9e0, Sep 15 2014, 12:56 PM.
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| Elijah Cross | Mar 16 2016, 04:59 PM Post #17 |
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Advanced Member
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What was limiting about the challenge set so far? Granted, it's a been a long time since I added any text - I've had to put this on the back burner for a while, but I'm about to work with a developer on this. Basically, I'm asking how much ciphertext would you like me to produce? Also, I'm bumping up the reward to $100. |
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| Elijah Cross | Dec 8 2017, 07:15 PM Post #18 |
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Advanced Member
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This challenge is still open, though enough time has passed that I've forgotten the keys. Also, I think a way around the issue of a digraph possibly giving away that the plaintext/key letters are the same is to have a key that is exclusively digits; encrypt any digits in plaintext as words ("1" becomes "one", etc.) or have the letters A through J represent 0 through 9. Doing so would prevent a certain digraph from appearing in the ciphertext, and therefore, gives away which of the ADFGVX letters equals 0, and when a plain/key pair are in the same row/column, but as of right now I'm not sure that helps unravel things. Finally, if anyone can tell me how/where to use the code provided in post #15, I'd appreciate it. Forgive me for being a complete programming noob. Edited by Elijah Cross, Dec 14 2017, 12:52 AM.
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1:02 AM Jul 11