AutoKey Cipher

  1. Key in a word or a short phrase in the top box
  2. Enter a KEY LETTER
  3. Press Encipher or Decipher
  4. The results appear in the bottom box

To "Break" a secret message that was enciphered with an AutoKey Cipher, place the message in the top space, enter a Key Letter and click Decipher. If the message does not appear, change the Key Letter and Decipher again, trying all Key Letters in turn until one Key Letter reveals the secret message.

Try this secret message - DUPO KOBXQAU SQNSHB TW EEAG HJ FANWC

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Key Letter


(A JavaScript program written by Jim Hannon for Secret Code Breaker)