slides/keyword-encipher.html

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  47
  48 # Keyword ciphers
  49
  50 a | b | c | d | e | f | g | h | i | j | k | l | m | n | o | p | q | r | s | t | u | v | w | x | y | z
  51 --|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|--
  52 k | e | y | w | o | r | d | a | b | c | f | g | h | i | j | l | m | n | p | q | s | t | u | v | x | z
  53
  54 * Taking a more Pythonic approach
  55
  56 ---
  57
  58 # The cipher
  59
  60 * Still character-by-character substitution, still monosubstitution.
  61
  62 Ciphertext alphabet: start with a keyword, write out the rest of the alphabet, removing duplicates.
  63
  64 ## Three variants
  65
  66 Write out the rest of the alphabet...
  67
  68 1. ...starting from 'a' (keywordabcf...)
  69 2. ...starting from the last unique letter of the keyword (keywordfgh...)
  70 3. ...starting from the largest letter of the keyword (keywordzabc...)
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