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Published on Jul 2, 2010
A quick'n'dirty 30-second stop-frame animation from Nick Pelling, attempting to demonstrate how John F. Byrne's 1918 Chaocipher works. (1) The characters on the right (plaintext) rotor and left (ciphertext) rotor appear in matching sequence; (2) The two rotors rotate anticlockwise and clockwise (respectively) until the plaintext rotor's letter 'A' is at the top (which Byrne called 'zenith', marked here with a '+'); (3) The left rotor is 'permuted', which means that the letter just to the left of the zenith is removed, all the letters round to the bottom (the 'nadir') are shunted round, and the letter removed from the top is reinserted at the bottom; (4) The right rotor is also 'permuted', but in a subtly different way (5) Both permuted alphabets are ready for the next letter to be enciphered or deciphered.