Newspaper article collection

August 25, 2012 · by · in Uncategorized

While Zamantha was digging up Thomas Dougherty’s letters at the San Francisco Public Library, she also made copies of their collection of newspaper article clippings.

The collection contains an assortment of Zodiac-related articles from 1978 to 2009. Zamantha generously sent me a copy of the articles, and now you can view the entire collection online in Google Docs by clicking on this link.

Here is a summary of the articles contained in the collection:

Tip: When you open one of the articles in Google Docs, it will extract the text from the article. This makes the article searchable. Here’s an example:

Many thanks again to Zamantha and Traveller1st!

Thomas Dougherty’s “code theory”

August 23, 2012 · by · in Uncategorized

Thirty-seven years ago, a man named Thomas Dougherty came up with a Zodiac “code theory”, and mailed dozens of bizarre letters from the Hotel Warfield in San Francisco to United States federal judge Oliver Carter.


The letters were recently unearthed again from the San Francisco Public Library by researchers Mark (traveller1st) and Di (Zamantha). Di paid a visit to the library, obtained copies of all the files, and also discovered that they had been previously found by “Goldcatcher / Blaine Blaine”, the person who originally promoted suspicions that Richard Gaikowski was the Zodiac killer (read more here and here). Goldcatcher refers to Dougherty in his report:

Some of the most pathetic Zodiac suspects included ” my Uncle Bubba the Zodiac” – this Zodiac suspect turned out, like most of the others, a joke foisted on an ignorant mass media; and someone living in a tenderloin hotel room with a bottle of wine who got drunk and began believing the son of Howard Hughes was the Zodiac according to his written decoding illusions.

Di generously gave me a copy of the Dougherty files, which I’ve scanned and put online. You can read the letters in their entirety here.

Was Thomas Dougherty on to something with the Zodiac ciphers? Let’s examine his approach. Here’s how he describes his method:
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New FBI files

August 20, 2012 · by · in Uncategorized

Updated Oct 17, 2014: Fixed the Google Drive link to the FBI files.

Diligent researcher morf13‘s persistence recently paid off: He received over 800 pages of never before seen material from FBI files on the Zodiac case. Click here to view all of the new documents (thanks, Mark, for uploading them). The files contain a wide variety of material related to persons of interest investigated for the Zodiac crimes. Inside the files you’ll see handwriting samples, letters, envelopes, crime reports, interview transcripts, emergency call logs, evidence analysis, and even a suspect’s day planner. The files also contain some unconfirmed Zodiac letters, and a lot of material related to Gareth Penn’s oft debunked theories about the killer and his codes.

This cryptanalyst’s conclusions about Gareth Penn’s strange code theories says it all:

 

 

Alas, that conclusion is reached all too often when analyzing the many claims that have emerged over the years.

And speaking of codes, here is one that appears in the files:

 

 

The files don’t seem to mention this code in any way. At first glance, it resembles a book cipher like the Beale ciphers. But Quicktrader on Morf’s forums was quick to point out the code’s resemblance to a Vigenère cipher matrix, due to the way the numbers repeat in an aligned pattern.

The matrix appears with a lot of other material, including handwriting samples, and this crossword puzzle:

 

 

Perhaps someone’s interest in puzzles aroused the suspicions of investigators.

Have a look at the new documents. Can you find anything interesting?

In his own words

August 12, 2012 · by · in Uncategorized

Forum user 4on4off had an interesting idea: Why not run the Gutenberg crib search program again, but against the Zodiac’s own writings instead of the massive collection of books in the Gutenberg collection?

I ran the search, and it found a few matches. Here are the files containing the results:

Results for the 408 cipher
Results for the 340 cipher

In each file, the matches resulting in the highest Zkdecrypto scores are displayed first. Here is a sample line from one of the files:

37, 237, +yBX1*:49CE>VUZ5-+|c.3zBK(Op^.fMqG2Rc, RSEENSIGNEDYOURSTRULEYHEPLUNGEDHIMSEL, 15, 1.8402534E-5, {0 17} {2 23} {20 29} {19 36} , 2952.125, 79.78716

And here’s an explanation of the data format:

  • 37: Length of chunk
  • 237: Position of chunk. Positions start at 0.
  • +yBX1*:49CE>VUZ5-+|c.3zBK(Op^.fMqG2Rc: Transcription of cipher text chunk
  • RSEENSIGNEDYOURSTRULEYHEPLUNGEDHIMSEL: Plain text chunk
  • 15: Number of unique letters in the plain text
  • 1.8402534E-5: Constraint difficulty. Lower values reflect higher difficulty (due to larger numbers of repeated symbols)
  • {0 17} {2 23} {20 29} {19 36}: Positions of repeated symbols, grouped into pairs
  • In the data for the 408, another value appears before the Zkdecrypto score, representing the proportion of characters in the solution that match the real known solution.
  • 2952.125: Zkdecrypto score
  • 79.78716: Zkdecrypto score divided by chunk length

What do you think? See anything interesting?

Harold Kravcik’s 340 solution

August 11, 2012 · by · in Uncategorized

Harold Kravcik created a stir a few years back when he produced a solution to the 340-character cipher. Some people believed it to be the correct solution, so it was submitted to the FBI, and Harold required others to sign non-disclosure agreements to view his solution. This led to a lot of hype that the decades-old mystery of the 340 cipher had finally been solved. But eventually, confidence in his solution was lost. The drama resulting from all this caused Harold, and others who believed in the solution, to receive ridicule and derision from folks in the Zodiac community who are exhausted by the parade of discredited cipher solutions that have emerged since the Zodiac killer committed his awful crimes.

But what’s wrong with Harold’s solution?
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Gutenberg addendum: Small ciphers

August 11, 2012 · by · in Uncategorized

The program I wrote for the Project Gutenberg crib experiments also looked for pieces of text that fit into the entire 13-character cipher.


This cipher has many repeated symbols: One symbol repeats three times, and three other symbols repeat twice. Nevertheless, the program found over 2,700 unique bits of text that still fit “as is” into the the cipher text. Here are some interesting examples:
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Throw the book at him, Part 3

August 9, 2012 · by · in Uncategorized

Back in Part 1 we talked about the idea of using a large collection of books as a source of cribs to plug into cipher texts. Can we use a large collection of books, such as Project Gutenberg, to find pieces of real solutions to the ciphers?

I created an experiment to explore this idea. First, the 408 and 340 ciphers are broken down into chunks. Each chunk of cipher text must have some minimum number of repeated symbols. Chunks that have many repeated symbols are difficult to find solutions for, since the solutions must have repeated letters in the exact same locations. If we pick chunks that have too few repeated symbols, then there are way too many solutions that will fit.

Then, a program processes all of Project Gutenberg’s books. Each book is converted into a stream of uppercase text, with all punctuation and numbers removed. For example, here is what the beginning of A Tale of Two Cities looks like when it is converted:

ITWASTHEBESTOFTIMESITWASTHEWORSTOFTIMESITWASTHEAGEOFWISDOM
ITWASTHEAGEOFFOOLISHNESSITWASTHEEPOCHOFBELIEFITWASTHEEPOCH
OFINCREDULITYITWASTHESEASONOFLIGHTITWASTHESEASONOFDARKNESS

The program then looks through all of the text from the books to find pieces that fit into the chunks we created from the cipher texts. In total, the program examined over eleven billion characters of text.

It is a bit like finding a needle in a haystack, since the chances are low of finding a long piece of text that exactly matches the real solution. Actually, it’s a bit worse than finding a needle in a haystack: It is more like finding a needle in a needle stack, because very many pieces of text can fit into a chunk of cipher text. You have to come up with a way to figure out which needle is the one you’re really looking for.

For example, take a look at this 46-character chunk of cipher text from the 408-character cipher:
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Cipher skin art

August 5, 2012 · by · in Uncategorized

Have you ever wanted to do cryptanalysis on someone’s back?

This is the Zodiac eating

August 2, 2012 · by · in Uncategorized

The latest tip jar doodle by a hot dog vendor in San Francisco shows a familiar figure with a brand new puzzle for you:

Can you solve it before your frank gets cold?

UPDATE: The tip jar doodle artist emerged, and posted the following background info on Morf’s Zodiac forum:
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Zodiac Typewriter

August 1, 2012 · by · in Uncategorized

In our many online discussions of the Zodiac’s ciphers, I’ve often needed to create pictures of symbols or pieces of the cipher text to illustrate a point. This became tedious after a while, so I created the “Zodiac Typewriter” to make this task simpler.

The Zodiac Typewriter gives you a quick way to string together a set of symbols to save as HTML (for blogposts and web pages), or as BBCode (for forum posts). It also generates hyperlinks so you can share your chunks of cipher text. This is so much faster than creating homemade, custom images. For example:

Here’s how to use it:

First, enter some text into the input box:

As you type your text, the generated cipher text image will appear below:

Each of the available cipher symbols is displayed in a table, along with the corresponding letter you can type to use it. The symbols come from the 408, 340, 13, and 32 character ciphers:

To use a symbol, enter its corresponding letter into the input box. Or, while your cursor is in the input box, click on one of the symbols. If you enter an unrecognized letter, a red question mark will appear.

If the table of symbols gets in your way, click the “hide” button.

Click the “lighter” button to make the cipher text gray. You can then click the “darker” button to make it black again. Maybe we’ll make this thing support more colors in the future.

When you’re happy with the cipher text, you can share it in several ways. One option is HTML, which is simply a collection of image tags that link directly to the images for each symbol. Click the “show html” button and you’ll see the HTML source. Copy and paste it to your blog post or web page and you’ll see the cipher text.

Another sharing option is to use BBCode for forum posts. Click the “show bbcode” button and you’ll see the bbcode necessary to reproduce your cipher text in a post. It is a collection of image tags, just like the HTML source. Simply copy and paste the BBCode into your post.

Finally, you can link directly to your cipher by clicking the “show links” button, which will generate hyperlinks for your cipher text. The “Full” link will open your cipher in the full Zodiac Typewriter interface. The “Compact” link opens a page that displays only your cipher.

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