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Any advice for complicated ciphers?

The Empty Vault Forums Bureau of Security and Signals Intelligence Forum Any advice for complicated ciphers?


  • This topic has 1 reply, 2 voices, and was last updated 4 months ago by madness.
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    Hello! This is my first time attempting the cipher challenge and I’d like some advice. What’s the best way to approach more complicated ciphers, such as rail fence and Vigenere. I’ve tried programming decoders with poor results and, especially in the case of the rail fence cipher, I don’t see a logical way to manually decipher text encoded in this way. Are there any tips anyone can share?


    The only hard part is determining how long each line is when you cut the ciphertext up, and
    you can figure that out by dividing the length of the text by k + (k-2) where k is the number of rails,
    and looking at the remainder.
    Then you just bounce from line 1 to 2 to 3 to 4 to 5 to 4 to 3 to 2 to 1 …. (for key=5, for example).

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