I’ve examined the encyclopedia of observations (http://zodiackillerciphers.com/wiki/index.php?title=Encyclopedia_of_observations) once again and tried to find connections between the observations. Of course this had been done before lots of times but I wanted to do this on my own. Thereby I made an observation that may have not beed discussed yet. If someone had the same idea we can delete my thread of course. Since I don’t want to post things that are already known I post only a summary and my conclusion. If you are interested I can post my sheets and detailed results later.
I’ve examined the following observations by enciphering Jarlves plaintext library and compared the results:
- Repeated symbols by columns and rows
Odd/Even bigram bias
Upper/Lower bigram bias
P15/19 bigram peak[/list:u:1ofasy96]
To put it in a nutshell:
I think (like most others do) that repeated symbols in columns and rows is an good evidence that z340 was substituted horizontally. A vertical substitution or pure gibberish is very unlikely (unless the plaintext was gibberish).
P15/P19 bigram peak is "higgs boson" significant like david posted before. The odd/even and upper/lower bigram bias is probably just a coincidence.
Now I had the following question:
Where is the connection between P15/P19 and the repeated symbols in columns and rows? If you untranspose z340 by P15/P19 you get very high bigram repeats but the difference between row and column symbol repeats vanishes. Either one of the two observations can be true at the same time.
To sort things out I made another experiment: I transposed a plaintext by P19 and substituted it afterwards. In the final cipher text you can still see a bigram peak at period 19 and you still have the high difference in column/row symbol repeats.
Conclusion
If my experiments are correct then I should have found an evidence that if z340 contains a transpositioning step this definitely had been done before the substitution. Otherwise P19 and row/colum symbol repeats would not behave like they do.
Personally I don’t think that Zodiac transposed an already enciphered text since this would mean that he had to draw all those symbols twice. I don’t know…but I think this guy was lazy (that’s only an assumption). The crossed out „k“ in z340 confirms that he was not willing to write the whole cipher again after he made a mistake (I would have started again since I am pedantic). Maybe he decided to make sure the symbols are not as cyclic as in z408 because z408 was broken because of the cycled symbols (repeating bigrams like double L).
I agree and was also thinking the same thing. Encoding before transposition = more work. But, he only had the opportunity to do it once, and may not have thought that at first. I have always preferred transposition before encoding, but have never been able to reconcile the strange cycle score left right top bottom.
The cycle score should not be affected very much when substituting an already transposed plaintext.
What do you think?
By the way:
Since z340 and Jarlves plaintexts have 17 columns and 20 rows it is not very accurate to compare the symbol repeats directly. So I’ve counted the repeats in the rows and then transposed the ciphers into 20*17 before counting the symbol repeats in the columns.
Hey Largo,
Your conclusion is basicly what I have been saying for years now and I am glad you found out on your own. So yeah, we can probably rule out any unsubtle transposition after or during encoding in a transposition + substitution hypothesis. Subtle transposition is possible and would be more local or act over shorter distances, it could also be a thing like a few swapped columns, rows or other small units that would nevertheless cause huge decryption issues.
A period 15/19 transposition does act over longer distances and therefore could be thought of as having a more randomizing effect on the encoding over for instance a period 2 transposition. Though, a period 15/19 transposition can be made more local by for example transposing 5 individual parts of 17 by 4 and joining them together (but preferably use irregular parts as otherwise it would show up in periodic encoding analysis).
Nice analysis, Largo – it makes a lot of sense.
Jarlve, what other signs do you think point to transposition being done prior to encipherment, besides what Largo has already pointed out?
Jarlve, what other signs do you think point to transposition being done prior to encipherment, besides what Largo has already pointed out?
As Largo pointed out, it is more likely within such a hypothesis.
I have been taking a break. But wondering if the 340 may be a hoax. It has certain properties, but I wonder if those properties could be explained with some system of cycling through a table of symbols to make the 340 look like a message. The cycles intentional. The period 15 / 19 repeats, maybe evidence of the dimensions of the table, and completely unintentional. I think that we should debate this, maybe see if someone can come up with a hoax system to simulate some of the 340’s properties. I don’t need a message for a solution necessarily, just a solution to the puzzle. Any thoughts?
But wondering if the 340 may be a hoax.
It’s something that has lingered on my mind for a while now, more or less just treating it as another hypothesis. We could have some say about it if we happen to assume the correct construction method because ngrams could be trained to it.
Fashion yourself in the late sixties, you have no computer and want to make a fake/hoax cipher for the masses that can take a beating. How would you go about it?
Sometimes I also considered that z340 is probably just a hoax. But to be honest: I don’t like that idea since I want to read "the secret message that explains it all" and so I put the hoax option aside in the past. That is one of the reasons why I never give it a try to find a construction method for a hoax that behaves like z340.
But hey…why not? Maybe it is a good idea to view z340 in a different light. I have some ideas how to make a hoax that has cycles and repeated ngrams. I’ll give it a try.
I think that we should debate this
We should start a new thread when someone has an idea.
Sometimes I also considered that z340 is probably just a hoax. But to be honest: I don’t like that idea since I want to read "the secret message that explains it all" and so I put the hoax option aside in the past. That is one of the reasons why I never give it a try to find a construction method for a hoax that behaves like z340.
But hey…why not? Maybe it is a good idea to view z340 in a different light. I have some ideas how to make a hoax that has cycles and repeated ngrams. I’ll give it a try.I think that we should debate this
We should start a new thread when someone has an idea.
Largo, I would be very interested in hearing your ideas about a system that can create cycles and repeated ngrams.
