Monday, November 25, 2013

Code 64 : Pollux Cipher

Pollux Cipher


The Pollux cipher is based on the Morse alphabet which itself is composed of dots and bars. The Pollux cipher encodes this dots and bars but needs an additional separating sign to clarify that a new character begins.
Fig. 1: Morse alphabet

A translation table has to be created which could look like this:
 Cipher with numbersCipher with characters
Dot0,7,4A, H, O, V, C, J, Q, X
Dash1,8,5E, L, S, Z, G, N, U, B
Seperator2,9,6,3I, P, W, D, K, R, Y, F, M, T

Should the message "GEHEIMNIS" for example be encoded with numbers based on the Pollux cipher, it has to be translated into Morse code first. After that, each Morse code character has to be substituted according to the translation table.

The completely encoded message would be: "8149037704276002186597764743". It is obvious that the encoded message is much longer than the plaintext.


The characters in the ciphertext are evenly distributed because they are chosen randomly out of the translation table. A substitution by different characters or by different characters and numbers should be chosen to provide many alternatives, which makes a frequency analysis much harder.


The characters in the Morse alphabet occur with specific frequencies. The translation table however, leads to evenly distributed frequencies of characters in the ciphertext. This is also a variant of a homophonic substitution.



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