Is the 340-character cipher real?

Over forty years of frustration have passed since the Zodiac killer first sent his mysterious 340-character cipher to the San Francisco Chronicle. It only took a week for two teachers to solve his previous cipher. But many thousands of people, over four decades, have tried to crack the mystery of the 340-character cipher, to no avail. You may have seen many would-be solutions in news stories and on the internet. The 408-character cipher was solved with a definitiveness that defies any possible doubt, because it is impossible for the Harden’s key (Part 1, Part 2, Part 3) to produce such an easily understood plain text message purely by chance. No such solution yet exists for the 340, despite numerous claims to the contrary.

So, with so much failure and defeat confronting us, should we just accept the possibility that the killer, frustrated by the swift unlocking of his previous secret message, simply created a fake cipher to keep us all busy all these years?

True crime author Michael Kelleher recently asked me if there was a way to know for sure if the 340 had a real message hidden away under its mysterious symbols. Our conversation evolved into this article:

Cipher Legitimacy

The short answer is: We don’t know if there is a legitimate message in the 340-character cipher. But the cipher text shows us many interesting and peculiar features that continue to draw us into its trap. Why would these features be there if there is no underlying hidden message?

If it was a hoax all along, then it was a really, really damned good one.

4 comments on “Is the 340-character cipher real?

  1. Terence on said:

    Call me a crytography newbee, but in my understanding of ciphers, similar letters/symbols lead to similar letters. Why, even if he liked using the word “I” and “Kill” would someone that wanted the cipher broken not use this predominate format?
    Also, I did not like that, in the movie and/or book, the cipher ended with gibberish. I tried to see any and all patterns in the cipher and had to ask myself if some of the characters were really spaces and not letters. I am sure that this was considered, but I think an address did pop up in this way (but not in the accepted cipher that did not lead to his being caught/arrested anyway).

  2. admin on said:

    There is strong evidence that the killer padded the 3rd section of the 408-character cipher with junk symbols “pulled down” from earlier in the cipher text. For more information on this, read this thread.

  3. Pingback: » Blog Archive » New home for Zodiac cipher material

  4. treehouse on said:

    Finally, a website to begin on a journey to understanding how to begin cracking all the codes! If you take a look at all the potential suspects, Penn makes the most sense (without much knowledge about his actual alibis, whereabouts etc; which I am have not researched yet).

    1) He fits the profile of a man eager for attention, but intelligent enough to hide behind an alias (i.e. the “obsessed” sleuth who has the perfect harmless “strawman” O’Hare
    2) He is able to hide behind the obsessive sleuth persona in order to continue to show the world that he is smarter than all of us
    3) He has to give us “clues” in order to stay in the “game”
    4) His extensive knowledge of codes, rhymes, a true “Renaissance Man”

    Penn- Please help me understand your codes from the beginning, I would love to journey down the code road with your guidance!

Leave a Reply

Your email address will not be published. Required fields are marked *


53,605 Spam Comments Blocked so far by Spam Free Wordpress

You may use these HTML tags and attributes: <a href="" title=""> <abbr title=""> <acronym title=""> <b> <blockquote cite=""> <cite> <code> <del datetime=""> <em> <i> <q cite=""> <s> <strike> <strong>