I’m not sure if it has been compiled previously. Either way v.nice. Thanks for taking the time to consider & compile it.

In the 408 cipher, Z had used 7 symbols for the letter ‘E’ and 5 symbols for the letter ‘N’. All other alphabetical letters were represented by 4 or less homophones.

The amount of homophones had not been chosen according to the cleartext’s letter frequency.

However, a frequency-like distribution of homophones (e.g. ‘E’ the most frequent) is present and thus leads to the conclusion that Z had chosen the amount of homophones according to a separate frequency table. Such frequency tables imo were rare around 1970 and most likely available in cryptology books. As it is quite unusual to choose the letter ‘N’ as the second most frequent letter, the frequency table Z might had referred to must have consisted of a smaller, imprecise sample.

I would not be astonished if one of those books contained such an imprecise frequency table plus explaining the method of homophone substitution.

QT

HS: Thank you for doing the research and posting this information. I will look at some of these books. It would be nice to own all of them. Smokie

HS: Thank you for doing the research and posting this information. I will look at some of these books. It would be nice to own all of them. Smokie

Great..I’d do that, too, but most of them are not available in our German libraries

QT

David Kahn’s "The Code Breakers" is useless for Zodiac research. It’s interesting and all, I read the whole thing, but it’s more of a history book than anything else. I got it through intra-library loan, and was disappointed. Almost nothing in it at all of how to make codes, etc.

-glurk

I read Laffin’s "Codes and Ciphers: Secret Writings through the Ages" book with the zodiac ciphers in mind. There was nothing in there that jumped out at me or suggested that zodiac referenced this book.

I’m guessing the book "Secret and Urgent: The Story of Codes and Ciphers" by Fletcher Pratt (1942) would be a good one to look into as it reference homophonic substitution.

David Kahn’s "The Code Breakers" is useless for Zodiac research. It’s interesting and all, I read the whole thing, but it’s more of a history book than anything else. I got it through intra-library loan, and was disappointed. Almost nothing in it at all of how to make codes, etc.

-glurk

You deserve a medal.

I have it. I had no idea how lengthy it was until it arrived in the mail. It now sits in my closet. I do have a couple of the others, which I did read. Good list Squid!

HS: I suggest that you add those other two books to the first post, and then add members’ notes about the books under them.

Also, some of the books may be online. It is a good research project.

My personal interest is in different examples of how to shuffle plaintext before encoding.

I’m not sure if a list of cipher, cryptogram, and secret writing books published prior to 1970 have been listed yet.

I heard this tid-bit about ciphers on the National Geographic documentary "Code Breakers" featuring the zodiac 340 cipher. A computer scientist by the name of Ryan Garlick from the University of North Texas said, “he (zodiac) may have used some books that were available at the time. So, if chapter 1 of that book is homophonic substitution ciphers, and we know that that’s how the first solved cipher was encoded, then we definitely want to look at chapter 2 in that book to see how this one (the 340 cipher) might be decoded."

Here’s a list of books I could find published prior to 1970, yet still within range for someone to own the book or check it out from the public library:
a) Codes and Secret Writing by Herbert Spencer Zim 1966
b) Codes and Ciphers: Secret Writings through the Ages by John Laffin 1967
c) The Code Breakers: The story of secret writing by David Kahn 1967
d) Cryptography: The Science of Secret Writing by Laurence D. Smith 1955
e) Secret Writing: An introduction to ciphers, cryptograms, and codes by Henry Lysing 1936
f) Secret Writing: An introduction to ciphers, cryptograms, and codes by John L Nonovic 1936
g) Cloak and Cipher: A History of Secret Writing by Dan Tyler and Martha Moore 1962
h) Secret and Urgent: The Story of Codes and Ciphers by Fletcher Pratt 1942
i) The First Book of Codes and Ciphers by Sam Epstein and Beryl Williams Epstein 1956
j) Secret Codes and Ciphers by Bernice Kohn Hunt 1968
k) Fun with Cryptograms by Joseph Verner Reed 1968
l) Secret Code Book by Francis W. Keene 1955
m) An Invitation to Cryptograms by Eugenia Williams 1959
n) Cryptanalysis: A Study of Ciphers and their solution by Helen Fouchel Gaines 1956
o) Secrets with Ciphers and Codes by Joel Rothman and Ruthven Tremain 1969
p) How to Write Codes and Send Secret Messages by John Lawrence Peterson 1966
q) A Guide to Codes and Signals by Gordon A J Petersen 1942

Very good list and great idea. It would also be a good group project to build a matrix of what types of cyphers can be learned from each book. From that, we might have a list of encoding methods he could have used for the 340. Then, eliminate the ones already heavily tested and we might just find his method.

The Cowboy Code ..Secret Code Book for boys and girls by Francis W. Keene first page up I think..

one would expect the scumbag to use a book of more significance.. but ya never know

I had noticed the Laffin book in an earlier post in another thread. Riverside CC has it, but from the call # you can tell it is a second copy. Makes you wonder where the first may have gone.

-m

The Cowboy Code ..Secret Code Book for boys and girls by Francis W. Keene first page up I think..

So how many unique symbols z used appear here

Looks like only 7. And this looks like very basic simple substitution. I doubt Zodiac ever even saw this book.

Circles, squares, triangles, letters and plus signs are very common things, after all.

-glurk