MYSTERY WIRE — The United States Federal Bureau of Investigation has officially recognized Melbourne mathematician Samuel Blake and two other cryptologists, American David Oranchak and Brussels based software programmer Jarl van Eycke, for solving a 50-year-old encrypted message written by the unnamed serial killer known as “the Zodiac”.

Dr Samuel Blake worked on decrypting the message known as the “340 cipher” with the help of a University of Melbourne supercomputer called Spartan.

This is a file copy of a cryptogram sent to the San Francisco Chronicle in 1969 by the Zodiac Killer. A coded letter mailed to a San Francisco newspaper by the Zodiac serial killer in 1969 has been deciphered by a team of amateur sleuths from the United States, Australia and Belgium, the San Francisco Chronicle reported Friday, Dec. 11, 2020. (San Francisco Chronicle via AP, File/San Francisco Chronicle via AP)

The cipher was sent to the San Francisco Chronicle newspaper on November 8, 1969 by a person who called himself “Zodiac”.

The Zodiac sent letters up until 1974, including proof he was responsible for the deaths of at least five people in the San Francisco Bay Area.

“The chances of solving this after 50 years was next to zero and so being able to play a role in this is fantastic. You know, I hope this decryption may lead to better narrowing down who this person is but I guess we’ll have to wait and see. In regards to the other two ciphers that he sent, we’re looking at those to see if there’s ways in which we can use the work that we’ve done on the ‘340’ cipher to solve those but none of that is clear at this stage.”

Samuel Blake

The cracked cipher does not reveal a name as promised in separate letters by the Zodiac.

“It was such a long shot,” Dr. Samuel Blake said. “We tried several hundred thousand incorrect ways of solving the cipher and just by chance we happened to sort of stumble upon a fragment of how it could be solved and using that fragment we reverse engineered the entire solution and got the entire message out from the Zodiac.”


Blake also said he had been working on finding a solution to the cipher since contacting David Oranchak earlier this year.

“David Oranchak is from the United States and he’s been working on trying to solve this cipher in his spare time for 15 years which is a Herculean effort,” according to Blake. “I saw some of the videos that he’d put online promoting analyses that he’d done of this cipher and I thought they were excellent so I reached out to him I think about March of this year and it was sort of a way of getting through the Melbourne Covid lockdown was to play around with this in my spare time.”

The Melbourne mathematician now hopes to help crack the two remaining unsolved short ciphers: one with 13 symbols and the other with 32.