Ok….so I was researching some Z coincidences with some Lewis Carroll writings and publishers and came across Lewis Carroll’s Alphabet Cipher and how it is able to be cracked using Kasiski’s method. Some of his works were published by a company called Chatto and Windus, which were referred to as a company called Zodiac Books. They were published in the 1950’s I believe so I figured that Z would have access and may have researched more of Carroll’s writings.

Here is Carroll’s Alphabet cipher..

http://en.wikipedia.org/wiki/The_Alphabet_Cipher

And here is the Kasiski method:

In cryptanalysis, Kasiski examination (also referred to as Kasiski’s Test or Kasiski’s Method) is a method of attacking polyalphabetic substitution ciphers, such as the Vigenère cipher. It was first published by Friedrich Kasiski in 1863,[1] but seems to have been independently discovered by Charles Babbage as early as 1846.[2]

The Kasiski examination allows a cryptanalyst to deduce the length of the keyword used in the polyalphabetic substitution cipher. Once the length of the keyword is discovered, the cryptanalyst lines up the ciphertext in n columns, where n is the length of the keyword. Then, each column can be treated as the ciphertext of a monoalphabetic substitution cipher. As such, each column can be attacked with frequency analysis.

The Kasiski examination involves looking for strings of characters that are repeated in the ciphertext. The strings should be three characters long or more for the examination to be successful. Then, the distances between consecutive occurrences of the strings are likely to be multiples of the length of the keyword. Thus finding more repeated strings narrows down the possible lengths of the keyword, since we can take the greatest common divisor of all the distances.

The reason this test works is that if a repeated string occurs in the plaintext, and the distance between corresponding characters is a multiple of the keyword length, the keyword letters will line up in the same way with both occurrences of the string.

http://en.wikipedia.org/wiki/Kasiski_examination

So, has this method been tried to see if there is a repeating 3 symbols every so often in the code or something similar? Or has this method been used before at all to try?