Mr. Oranchak is a friend of mine, and as I have explained before, he and two other gentlemen solved the Z340 last year. The other Zodiac cipher, the Z408 was solved in 1969.
He will be giving presentations to both the FBI and NSA later this year on how the Z340 was solved. I’ll post it here when I can.
I thought this article was interesting, where the author mused that possibly Zodiac got his idea about how to make the Z340 more complicated than the first cipher, from newspaper article at the time.
i.e
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Login"But what inspired the added complexity and the diagonal shift employed by the Zodiac Killer in his encryption technique on November 8th 1969. The trigger may have been his 408 cipher and the detailed attempt to break it in the Vallejo News Chronicle on August 4th 1969, at a time when the Zodiac Killer would undoubtedly have been scrutinizing the newspapers for progress on his 408 cipher."
The cryptogram fan from San Francisco, a graduate student, made some observations regarding the 408 cipher (shown on the left). While his analysis wasn't wholly accurate, it is this newspaper article that may have bearings on the technique employed by the Zodiac Killer when designing his 340 cipher. On page two of this newspaper article it continued "The pattern beginning to take shape apparently will end up a three-tiered diagonal structure composed of sections, of each of the three ciphers."
The Zodiac Killer's 340 cipher, that followed the October 13th 1969 letter, was three-tiered just like the 408 cipher, but crucially it was structured diagonally for the majority of the coding, as postulated in the newspaper. The title of the newspaper article was Text Of Letter May Offer Clues, but did it offer the inspiration for the Zodiac Killer to create a diagonal shift in his 340 cipher just three months later?
The idea of why the Zodiac did his Z340 that way, is vastly interesting. Even the fact that he had an apparent error in transcription.
Non-linear thinking (either through error or intent) can be so great at confounding.