John Rose from Australia has uncovered some interesting features within the Zodiac Killer's unsolved 340 Cipher, mailed to the San Francisco Chronicle on November 8th 1969. This does not tackle the entirety of the cipher, as the extremities of the code still remain unbroken. What it does do however is show an extremely promising correlation between the 340 Cipher and Halloween Card, using predominantly 81 characters in a 9 X 9 grid formation at the center of the cipher. It has been achieved using nothing more than Dave Oranchak's Web Toy, implementing zkdecrypto cipher-cracking software. The tool can be found on the Zodiac Killer Ciphers website here. If you place the following letters into the Web Toy, you can recreate the results shown in the grid below. For further correspondence on this matter email: [email protected]
