Rotor Machines

• Each rotor maps 26 characters on the front face to 26 on the back face
• Simple substitution cipher
• After each encoding rotation changes the mapping
  • Introduces polyalphabetic element with period 26
• The output of one rotor feeds the next
  • Introduces function composition
• The key is the rotor wiring, placement, and initial position
• Used by the Germans during the WW2
• Cryptanalyzed by the British using electromechanical computers

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 Last change: Friday, June 11, 2004 5:38 pm
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