| Viewing Single Post From: Announcement: Official Vigenère Tutorial | |
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| insecure | Oct 11 2005, 03:31 PM |
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Elite member
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Donald was talking about cracking a Vigenere, not using one. To use a Vigenere is easy enough. Pick a codeword. Example: NOTASTRONGKEY Remove all duplicate letters: NOTASRGKEY Using a Vigenere square... oh. To construct a Vigenere square, take a square 27 cells by 27 cells in size. Top row, starting at column 2, write the alphabet. Left column, starting at row 2, write the alphabet. Rows 2-27: starting in column 2, continue the alphabet started in column 1, re-starting from A when necessary. Top bit of table looks like this:
and so on. Locate your plaintext letter on the top row. Locate your key letter on the leftmost column. Where that row and column cross, is your ciphertext letter. Move on to next plaintext letter and next key letter (starting at the beginning of the key if you reach the end), and go round again until you run out of plaintext. |
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| Announcement: Official Vigenère Tutorial · News | |
8:31 PM Nov 24
