QT

We do know that the 340 cipher shows up with

26^64 = 9.106685769537214956799814036095e+33 possibilites to configure all homophones. Needle in a - very large - haystack.

The initial set-up of

IoFBc
dNp
kdW

as well as the symbols

L, l, C, z

might be a possibility to 'attack' the cipher (technical issue: Oranchak's great z typewriter links get removed automatically?).

Thus, by preselecting some most frequent n-grams, there now is a total of 65 quintgrams and 2x300 trigrams running in the program (besides the other symbols mentioned before).

In other words, the program simulates a total of 12 letters or

26^12 = 9.5428956661682176e+16

variations - all to be checked against a pretty large dictionary (~4,500). As we have to admit, this still is almost nothing compared to the full strength of the cipher.

Another thing which has been added/improved: From now on, the level of (basic) set-up is called ZEROH and from there on ALPHA, BETA etc. for each 'success' (=words found at specific locations in the cipher). Also, for each of those levels, the amount as well as the length of the words to be found can be defined accurately.

Interestingly the program is getting better in producing 'readable' phrases. Please still keep in mind that both, the program and also the method did not exist before. Of course it is still a long way to go - if possible at all - but here you go with another screenshot of what the program is actually capable of, so far.

QT

I think you and I agree that there's more to z340 (and maybe other ciphers) than has been discovered so far but I think we have different ideas about how z340 was made and how best to approach it. From my perspective, we have a very credible solution to the z340 already so any additional information I might find will have to incorporate the existing solution somehow.

"It's a matter of logic: The Z340, as a homophone substitution, is way more complicated than the Z408. First of all, no need to use transposition/anagramming etc."

Although a simpler cipher, the z408 can be cracked by automated solvers in a matter of seconds these days. It would be interesting to generate a large number of random homophonic substitution ciphers with the same characteristics as z340 and checking if they could also be cracked automatically (I suspect they could).

"Imagine: Transposition, Anagramming, Line shifting, Homophones - in the end you can write into the cipher whatever you like to, as long as you keep on shifting/explaining."

I definitely agree that transposition is often abused by people who're driven by wishful thinking, sensationalism or even book sales. However, I also think transposition can be a completely valid technique. To distinguish "good transposition" from "bad transposition", I typically look for a simple and consistent pattern or algorithm. For example, I don't think anagramming is very convincing whereas columnar or periodic transposition can be. It's hard to put into words but I know it when I see it :)

In this example I defined for the first strings to find at least one word, for all the other strings one word each. The results were THOSE TOTAL STEEL TOOLS TOWNS. Other results may come up, of course.

The video shows the first result being found. Letting run the program for a while, dozens of such show up. Also you can see the first letter is defined for the + symbol, followed by others. The longer string with the double letter is from line 17/18 of the cipher.

The current 'setting' covers 181 symbols or 53% of the total cipher.

Regarding your question:

Yes I stick with the cipher to be a homophone substitution, like the Z408 (without transposition etc.). I do not comment on other 'solutions' or trials to find such as long as I can't come up with a complete cleartext. Normally, I'd expect about 8-10 spelling errors in a homophone cipher of such length. Not many other encryption methods known/credible to cope with such a type of cipher, if at all. It's a matter of logic: The Z340, as a homophone substitution, is way more complicated than the Z408. First of all, no need to use transposition/anagramming etc. Also, the type of cipher - more than 26 homophones - complies with such type of encryption (so did prove the 408). Also, transposition usually uses alphabetical letters. Imagine: Transposition, Anagramming, Line shifting, Homophones - in the end you can write into the cipher whatever you like to, as long as you keep on shifting/explaining. I had warned about such method as someone can indeed start writing words into the z340 cipher structure, then start to use transposition/line shifting/anagramming to complete the rest - mostly with short words. That's what has been done and found (but lacks of longer words and logical text combinations such as 'car light', 'blood drop' etc.). Whatsoever, not my business.

QT

@jay Yes, Python :D. Regarding the 340 one may or may not describe it like this: Whilst searching for the highest mountain of the world, this one found might be the K, it might be the 'Annapurna'. Not as close to it as the K2 but not a flat find, either. 

Yes, python indeed - nice language! :) Anyway, what you're describing sounds like an analogy for a hill-climbing algorithm that gets stuck in a local maximum. Is that what you mean? As I understand it, that particular problem can be mitigated somewhat with techniques such as simulated annealing (wasn't that what Oranchak et al. used as well?)

Posted by: @quicktrader

Average word length, shifting, asthetics etc. - I leave that discussion up to others.

Since you mention that you don't use shifting (a form of transposition), are you treating z340 like a pure substitution cipher with no transposition? I.e. do you think the encryption scheme is identical to that of z408 but just uses a different key? I'd be amazed if you managed to produce a consistent and meaningful plaintext in this way considering that one has already been found using substitution and transposition!

Posted by: @quicktrader

For ya entatainment have uploaded a video (each figure counting covers a total of 361,431,457,920,000 words being checked on various positions of the cipher parts).

Sounds interesting... Where would I find this video?

Average word length, shifting, asthetics etc. - I leave that discussion up to others. Hopefully my prog sooner or later would produce all of those solutions (it does spit out plenty on parts of the cipher - but not the correct/complete one, yet).

For ya entatainment have uploaded a video (each figure counting covers a total of 361,431,457,920,000 words being checked on various positions of the cipher parts).

QT 

Considering that we now have a solution to z340, are you still working on this? I'm asking because I do accept the correctness of the published solution to z340 - more or less anyway - but I still have a sneaking suspicion that there's more to these ciphers that we haven't found yet.

It's entirely possible that I'm simply overestimating the abilities of the "cipher letter writer" but there are just so many loose ends that are often brushed aside or used to support the argument that the author must have been an amateur. I, however, would not be surprised if some of the typos and transposition errors in the ciphers are actually clues or remnants of additional cipher elements that we haven't found yet.

For instance, it's weird to me that z340 is split into 3 sections of 9+9+2 lines, that we see "LIFEIS" somewhere in the middle, that there are so many typos, that a character on line 15 needs to be moved to the left for the period 19 transposition to work, that the words on the last two lines are written forwards and backwards, etc. Perhaps it's all an attempt to complicate our lives but it's just not very aesthetically pleasing...

In z408 we also have a bunch of typos and what appears to be a missing word; often assumed to be "people". And then, of course, there are the last 18 characters which no one has been able to explain properly yet. They might just be filler but who knows.

I keep wondering if we're almost there with z408 and z340 but are still overlooking something. Maybe it's possible to produce slightly different plaintexts by inserting lines from one cipher into another, maybe some lines are inherently ambiguous and should be read in a mirror, maybe z13 or z32 are involved somehow?

Anyway, I wonder what you and other web sleuths think about these ideas?

P.S. since you seem to know python, I thought you might be interested in a script I wrote the other day to test if other Zodiac letters use the z340 enciphering scheme (none seem to so far)

My point is, that the solution I received from the man who claimed to be Zodiac,  works out to be correct and fits perfectly.  I agree it can be made to say something very different, but if this was actually from the horses mouth so to speak , it shouldn't be ignored. I believe Zodiac told the truth when he said his name was in the cipher, except it was not his full name, he wouldn't be stupid enough to do that! The name Robert was a common first name, and it also works with the first initial of the RH at Riverside.

I believe that his signing off on the desk poem with RH,  was the best clue to his real name and was his largest mistake! Let us not forget Darlene's own words: He was an "ole hippie". She told her babysitter his first name was either Bill or Bob. These were factual words spoken by the victim about the man she was followed by and who she was fearful of!  I gave the name Paul in Darlene's police report, because of a man who had acted suspiciously back in 1970. He had a solid alibi and was cleared.

EEBEORIETEMETHHPITI - Those letters could be fillers to complete the line of the cipher or indeed mean something. 'Robert the Hipie' is not the approach I would follow. Not knowing what you have or have not received and by whom (and in which year). However, there is some potential for clues in those letters: 

For example, one might extract the word 'mother' from those letters.

MOTHER  EEBEIETEHPITI

or, alternatively, the words 'meet' or 'met the other'

I MET THE OTHER - EEEBPII

which still is no solution. Same with   

MEET THE EERIE TO - BHPII

Many possibilities to play with those 18 letters..even found a 'complete' one:

I HIT THE PEER - MEET OBIE

Regarding multiple solutions for homophone ciphers: Yes, they could exist but is the 340/408 long enough to rather work with few if not only one, I guess (we may already have seen one of such for the 340 btw).

Finally, the first name of Z: He may have (had) two  first namea..my guess is his first is pretty sure 'PAUL'. Following his clues, I'd say the odds for this to be correct is 99.9%. He (often) gave clues in his communication and it took decades to figure out what he was actually referring to (bottom lid of a scotch tape / St. Paul, Minnesota). Well, who knows. 

"Maybe you play chess with me" - maybe his name was PAUL KING or PAUL BISHOP. The clue with the scuba gear is still foggy to me.

QT

I was given the solution by someone who claimed to be Zodiac himself! The last 18 was:" it me the hipie Robeet". It was put into my mailbox on a green card that was an ad for a flooring company named St Patrick's in Pleasant Hill Ca. St Patrick's day was Darlene Ferrin's birthday!

For whatever reason, he thought she and I were friends? The name Robert is the first name of one of my suspects. It is also a name that the FBI has for Zodiac's first name! R of course matches part of the desk at Riverside: RH. The FBI has 12 letters for the full name of Zodiac from one of his letters, Bob is short for Robert, my suspect fits the 12 letters if I use Bob instead of Robert. His last name is 9 letters long starting with H, which equals 12 letters!

The Hardens were very close to solving the last 18 they had: Robert Emmet the hippie. "Two" too many letters. The other clue given to me with the 18 letter solution was: 5 E's the 5th letter and three I's the 9th letter. ( There are 5 E's and three I's in the last 18! Harden's had the correct 18 letters, they just had them in the wrong order.  

QT, I would like your feedback on this, please?