In the Encyclopedia Of Observations the following question was asked:
(Source: http://zodiackillerciphers.com/wiki/index.php?title=Encyclopedia_of_observations#Other_observations_2)
The author of the cipher does not use the forward-facing letter Q as a cipher symbol, but uses a backwards-facing Q instead. Similarly, he does not use the forward-facing letter C as a cipher symbol in the 408-character cipher, but uses a backwards-facing C instead. Why doesn’t he use up all the normal alphabetic symbols before resorting to additional symbols and variations?
Maybe I found a pretty simple explanation. I think he created the keys for z340/z408 before he wrote the plaintext. The key was based on letter frequencies of general english texts and not of the plaintexts he wrote.
In the plaintext of z408 there are three unused letters: J, Q and Z. I think that one of these letters corresponds to the forward-facing letter C, which is missing in the ciphertext. The other two letters may correspond to cipher letters which were never used.
In z340 the forward-facing letter "Q" is missing. I guess that he mapped this letter to a uncommon one in his key too.
What do you think?
Largo
I think that 340 key may have had unused symbols. Maybe because unused symbols mapped to low frequency plaintext, or because ciphertext selection within a set of ciphertext that mapped to any particular plaintext followed some type of scheme that was in some way conditioned upon plaintext position.
The 340 is very cyclic, but not as cyclic as the 408. We still don’t know exactly why. Did he cycle his ciphertext selection in the beginning of the message to ensure diffusion, and then just get lazy and randomize selection toward the end of the message? Did he change the key at points throughout the message. Or was there some other type of scheme?
One fun project would be to examine the ciphertext cycles with the highest count of consecutive alternations, and look to see if the ciphertext are cycled as forward facing letters, reversed letters, and geometric shapes. I don’t know if anyone has done that before.
It is a very interesting subject.
Largo, that explanation makes a lot of sense. I’ve always wondered if, when writing the initial symbol assignments, he began distributing the normal looking symbols by writing down a key word or phrase under the plain text letters A through Z. Then he could assign additional symbols to disguise the symbol frequencies. Could the missing symbols C or Q complete such a word or phrase?
I think you are correct in that Z generated the key code before encoding the cipher.
it is interesting that the key space for Z340 63 (9×7) and Z408 54 (9×6) have factors of 9
I had a look at symbol sets that could align to 6,7 or 9 and found some but was inconclusive.
I can not recall anything else of interest that hasn’t been already documented by Doranchak.
The key space is an area i wish to look at once my current lines of investigation dry up.
Regards
Bart
Just to chime in here for a moment, I would also agree that Z created the key for the 408 based on normal, general, letter frequencies rather than those of the plaintext message itself. As the Harden’s themselves have said, it was the "L’s" that gave it away.
Whether this was by choice, or mistake, or accident, I have no idea.
-glurk
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I don’t believe in monsters.
I’ve always wondered if, when writing the initial symbol assignments, he began distributing the normal looking symbols by writing down a key word or phrase under the plain text letters A through Z. Then he could assign additional symbols to disguise the symbol frequencies. Could the missing symbols C or Q complete such a word or phrase?
I found an interesting link which shows a method to easily create a "keyed" key: http://crypto.interactive-maths.com/homophonic-substitution.html
Is this the kind of key generation you have mentioned?
By the way: If my guess about the missing "C" in z408 is applied to the z408 key, the "all roads leads to E" phenomenon is still working.
Yes, the "keyed" key is what I had in mind. But your hypothesis about him creating the key prior to creating the message seems to be a pretty good explanation for the missing C and Q.
