A certain Corey Starliper of Tewksbury, Mass claimed last month (July 2011) to have finally solved the famous-but-uncracked “340” (i.e. 340-glyph long) message sent in 1969 to the San Francisco Chronicle by the Zodiac Killer. Bless ‘im, but his so-called solution boils down to opportunistically choosing between multiple Caesar shifts, while modifying words and adding in extra ones where it all goes a bit Pete Tong.

Hence it should be no great surprise to most Cipher Mysteries readers that, however sincerely Mr Starliper believes his solution to be correct, I’m sure it’s basically a crock. However, the best thing about it is that it inspired Dave Oranchuk to post up a nice page demolishing it (though I personally wouldn’t call it a “hoax”, but rather a fairly typical example of the kind of self-convincing non-cryptology we’ve all seen countless times).

I don’t normally post on the Zodiac Killer ciphers (I’m more of a Renaissance guy myself), but plenty of people do find it interesting: to me, it has a home-grown 2d transposition feel to it, a bit like a lo-tech d’Agapeyeff cipher. Incidentally, I rather like Dave Oranchuk’s Zodiac webtoy, which lets you try out all kinds of crypto toolbox stuff on it (and indeed on various other ciphers). Enjoy! 🙂

3 thoughts on “Zodiac Killer 340 cipher cracked (…errrm, no, not really, sorry!)

  1. Ernest Lillie on August 22, 2011 at 10:08 pm said:

    Hello Nick.

    The story of Corey Starliper reads the same as many of the Voynich “cracks” that have appeared over the years — still interesting, though.

    Investigators of the crimes/ciphers can get their fill at:


    A dedicated forum is located at:


    I think I’ll stick with the Voynich for now — less chance of the author showing up to correct my decipherment errors!

  2. I may have been too eager at the beginning of all this to call his solution a hoax. But the longer he continues to hold back the “key” he used to come up with his plaintext letter assignments, the more it seems to move out of “over-estimating my own skill” territory into “purposeful deception”. He says he’s submitted the key to Quantico and the SFPD and will reveal the key once he’s had a response.

    By the way, I’d love to hear more about your thoughts about the Zodiac cipher. Do you have any more details about why you think it’s a home-grown 2d transposition?

    Many of the people surrounding the zkdecrypto project (a great software tool that successfully decodes many test ciphers encoded with homophone substitution) believe the 340 would have been cracked by now by software if the cipher was a “normal” homophonic substitution cipher. So, people have been trying all sorts of weird ideas: Quadrant-based layouts, columnar transpositions, Vigenere, spiral paths, etc.

    I’m curious if there’s anything specific about the cipher that makes it seem “odd” to you.

  3. 340newbie on August 1, 2012 at 11:29 pm said:

    http://www.340cipher.com is interesting.

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