A few days ago, I had a nice email from two Swedish engineers called Henrik (Henke) Sundberg and David Thelin: surprisingly, they claimed that they had worked out the details of the Zodiac Killer’s 32-character “map cipher” (also known as “Z32”).
The first thing I did was to put up a new page describing the Z32 cipher, something I’ve been meaning to do for a few years: as normal, I tried to cover the raw factuality and basic observations rather than out-and-out theories and speculation.
The short version is that the letter-shapes in the Z32 cipher look nearly exactly the same as the (famously solved) Z408 cipher, which makes it seem very much as though it too is a homophonic cipher, though with different letter assignments (deciphering it using the Z408 key doesn’t seem to yield anything sensible). Unfortunately, 32 characters (made up of 29 different shapes, i.e. only three appear more than once) wouldn’t normally be anywhere near large enough for a homophonic cryptogram to be cracked, unless you had some significant additional information to work with. (Hint: a cipher key would be a good start. 🙂 )
However, in this case there was some other extra information: a roadmap of the San Francisco Bay Area with a “Zodiac Killer” shape centred on Mount Diablo, and a note saying “The Map coupled with this code will tell you where the bomb is set. You have untill next Fall to dig it up“. A second “little list” letter (posted a month later) give a further clue: “PS. The Mt. Diablo code concerns Radians 4#inches along the radians“.
Sundberg and Thelin’s theory (described in this PDF file) is that it’s in fact a very scientific cipher, as much a stegotext as a cryptogram.
From this, they extract the phrases “C3H3”, “Octane”, and “North of West”, while “HCEL(Zodiac)PW(triangle)” reminds them of how the molecule HClO3 looks, centred around the Zodiac symbol. From which they deduce that they need to look 1 inch (i.e. 6.4 miles) along a vector due West from magnetic North.
Guys, guys… I’m really sorry, but I think you’ve got it wrong. Nobody in their right (or indeed wrong) mind would concoct a chain of reasoning based around a vague resemblance to a particular molecule in order to encode a unit vector. Even dear old Jessica Lee wouldn’t do that, much as she likes chemistry and ciphers.
Look: the Zodiac Killer wasn’t some evil scientific genius, he was a sick, unhappy man with a grudge against the SFPD (probably a surrogate for his sick unhappy relationship with his abusive, distant father) on a gun-powered external power trip, a (literally) vain attempt to right the perceived wrongs in his personal life. I don’t even think he knew properly what a “radian” is, because he doesn’t use the term correctly in his note.