The Zodiac Killer Cipher
Posted by Jonas Elfström Fri, 25 May 2007 16:31:00 GMT
The Zodiac Killer was a serial killer in the late sixties and maybe early seventies. He sent a number of letters to the press, including four ciphers or cryptograms and only one of them has been solved. The killer's identity remains unknown.
Chris McCarthy has a nice page about the cipher and he also has an ASCII version of the cipher.
Here's a small Ruby hack that calculates the character frequency using the ASCII version of the cipher. Feel free to use it if you like to have a go at cracking it!
EDIT: At this page you can have a go at cracking it real-time. I am not convinced it's really a homophonic substition cipher since the frequency analysis shows that the 340 does not have a flat frequency distribution.
It would be nice to know what cryptographic literature was available for the public in northern California in the late sixties.
UPDATE 2020-12-12: It's been cracked! Here's a video on how.
Mono-, Bi and Trigram Frequency for English
Hello,
It would be nice to know what cryptographic literature was available for the public in northern California in the late sixties.
I don’t want to seem like a smarta**, but it would have had to be something printed before or during the late 60s. The 408 was a simple substitution cipher. The 340 is most likely a substitution+transposition cipher. The number of permutations to test for this is enormous. I suggest testing in that area.
NewGuy
I’m the guy who took 3 days off of work in an attempt to crack the Zodiac serial killer’s last remaining undeciphered message. - A quite confused and confusing try.
Nice to see John Graham-Cumming having a go at it:
http://blog.jgc.org/2011/06/how-zodiac-enciphered-zodiac-408-cipher.html
http://blog.jgc.org/2011/06/identification-of-homophone-sequences.html
Corey Starliper claims to have solved the 340-character Zodiac Killer but it seems to be a hoax. http://oranchak.com/zodiac/corey/hoax.html