Members Of An Online Community Solved The 'Zodiac Killer' Cryptogram After 51 Years

Just like any other puzzles, a cryptogram is also a challenge on its own to whoever wants to solve one.

A cryptogram is a type of puzzle that consists of a short piece of encrypted text. Usually, the decipher needed to decrypt a cryptogram is present in the code itself, making most cryptogram solvable by hand. But one particular cryptogram, took 51 years to be solved.

That cryptogram, is the secret message from the 'Zodiac Killer', sent to the San Francisco Chronicle in 1969.

What’s known as the 340 Cipher, the cryptogram is one of the most mysteries of the Zodiac Killer’s murderous saga. And here, it has been decoded by a code-breaking team from three different countries.

From Virginia, U.S., web designer David Oranchak has worked with computer programmer Jarl Van Eycke from Flanders, Belgium, and mathematician Sam Blake from Melbourne, Australia.

As members of Mike Morford’s forum at ZodiacKillerSite.com, the trio codebreakers shared information, examined possible decryption methods, and searched clues which led to the crack the Zodiac’s cipher.

It was Van Eycke who created AZdecrypt, described by Oranchak as “a fast and powerful cipher solver.”

This is the full message from the Zodiac Killer that was hidden in the 340-character cipher for 51 years:

“This is exciting,” said Oranchak, the 46-year-old who said that he has been working on the Zodiac KIller’s codes since 2006.

“We’ve been sitting on the solution since last Saturday. When I first started looking at the Zodiac ciphers all those years ago, I thought, ‘Oh, I can just write a computer program and solve it,’ but it’s been kicking my ass all this time. Until now.”

“I could not have done this without them,” Oranchak said, referring to two of his fellow cryptographers.

“All of us in the crypto community on the Zodiac figured the cipher had another step beyond just figuring out what letters belonged to the symbols, and that’s just what we found here.”

In most cryptograms, the solution to decrypt the code is to figure out which of the letters are represented by certain symbols.

In the 340 Cipher, it turned out that the alignment of the words runs diagonally down the page, and occasionally as they get shifted over a column.

This method is known as the "transposition cipher."

Most ciphers used by computers rely on complex mathematics to scramble messages. Transposition ciphers on the other hand, are largely relics from the past that use rules to rearrange the characters or groups of characters in the message.

A basic scheme for it can be found in at least one U.S. Army code manual from the 1950s.

But still, this method is a complicated bit of code creation, Oranchak said.

The three cryptographers began breaking down the codes using different methods they think they found on the cipher.

Going through more than 650,000 different variations of the cypher text, the three slowly revealed some English words, by running them through the AZdecrypt for "many months".

After splitting the cryptogram and using the "cribs" feature in the software, they found references to “gas chamber” and “the TV show,” which seemed to refer to Jim Dunbar’s “AM San Francisco” show on KGO-TV that aired in October 1969. On that show, Dunbar and attorney Melvin Belli took a call from a person claiming to be the Zodiac, and he said, “I don’t want to go to the gas chamber.”

Revealing them, the cryptographers knew that they were on the right track.

“We knew we had something because of the Dunbar show,” Oranchak said.

“One of the interesting things about this is that it forces the minimum date of the cipher’s construction — maybe he had one and adjusted it, but it couldn’t have been in that form prior to Oct. 22, when the Dunbar show aired, and ... when The Chronicle got the 340 letter.”

The FBI acknowledged that the code had finally been cracked in a tweet:

Cameron Polan, a spokeswoman for the FBI’s San Francisco office, confirmed Oranchak’s claim. In a statement to The Chronicle, she said:

The 'Zodiac Killer' is the pseudonym for the American serial killer, who operated in Northern California from at least the late 1960s to the early 1970s.

The murderer targeted young couples, with two of the men surviving attempted murder. He also murdered a male taxi driver. The Zodiac himself once claimed to have murdered 37 victims, but only 5 victims are known.

The killer originated the name in a series of taunting letters and cards sent to the San Francisco Bay Area news agencies. These letters included four cryptograms, sent to prove the authenticity of the murderer's claims. The letters also included unreleased details and evidence from the crime scenes.

And this 340 Cipher was sent to the San Francisco Chronicle in November 1969. The cryptogram is also known as the Z-340, or simply the 340, because it contained 340 characters in it.

The authorities have sought ways to decrypt the Zodiac Killer's cryptograms to find clues about he killer's identity.