The Zodiac Killer’s cipher is finally solved after 51 years
In 1969, a serial killer terrorized Northern California with a very public yet covert persona. The Zodiac Killer murdered five people, though some called his methods “boring,” and rumors spin that number into more alarming figures such as 49.
Notably, he even threatened the media that he would keep killing if they didn’t publish his correspondences.
However, one of the most intriguing things about the Zodiac Killer was his ciphers. As per reports, the killer had mailed ciphers or encrypted messages.
The Zodiac Killer had sent the cipher in three parts to three local newspapers with a handwritten letter attached that confirmed his identity.
Donald and Bettye Harden, a puzzle-loving couple, deciphered the first encrypted message within days of its publication on August 1, 1969.
Bettye Harden correctly analyzed him as an attention-hungry individual who murders. His ciphers would begin with “I” and include the word “kill.” Moreover, the Zodiac Killer used a homophonic substitution cipher to encode a plaintext message.
But then, the Zodiac Killer upped the ante with the second cipher that hit the papers on November 12, 1969. “Either he knew codes, or had a good intuition about how to make them,” David Oranchak, a software developer and hobbyist cryptographer, said. “He definitely reacted to the Hardens[’] solution and made it much harder.”
The second cipher, known as Z340, resembled the first: a grid with letters, backward letters, shapes, and other symbols. No one could crack it. Many have tried it over the past 51 years.
But now, David Oranchak, Sam Blake, an applied mathematician, and Jarl Van Eyke, a computer programmer, have finally done it. They have cracked the code.
They thanked an engaged online community, the AZdecrypt software that Van Eycke created, and a little mysterious element called luck.
“By luck,” Blake said, “we discovered that (Zodiac) split it into three pieces and rearranged the message in a predictable diagonal pattern in the first two pieces.” He contained the message in the first two parts. The first cipher followed a logical pattern that read from left to right. But not this time.
The cipher revealed more about the Zodiac Killer’s motivations and personality. He made “an obvious effort,” according to Blake, to thwart deciphering the message by constructing the cipher in this way.
The resulting block of the text may have been intended to encourage the false assumption that the Z340 cipher was constructed with the same methods used to create the killer’s previous cipher.
By rearranging the message into three parts disguised as one block of text, the Zodiac Killer may have believed that most people would never look beyond its appearance to discover the actual method used to hide the real message.
However, the puzzle pieces kept falling into place once David Oranchak, Sam Blake, and Jarl Van Eyke started decoding it together.
Around the time when the Zodiac Killer sent the Z340 cipher, an imposter dialed The Jim Dunbar Show. The imposter claimed he was the killer, and he was scared of the “gas chamber”. That phrase, specifically, provided the key because of the text that had already been decoded at that point.
“When ‘that wasn’t me on the TV show’ popped out during the solve, I jumped out of my chair and said, ‘Holy ****!’,” Oranchak said. “That’s when I knew it was on the right track.”
They figured that a “gas chamber” would appear in this text. And it did.
The cipher highlighted that the “gas chamber” did not scare the Zodiac Killer. It is because the killer believed that the “gas chamber” would send him to “paradice”, where he has already sent some of his “slaves”. In fact, he killed people who would become his slaves in “paradice”.
Notably, another obstacle in the deciphering of the ciphers was misspellings. For instance, the spelling of paradise. It was probably done on purpose. But then, who knows? No one knows who this killer is, still.
Thankfully, the codebreaking software that Jarl Van Eyke built was powerful enough to provide fragments of the complete solution. Oranchak could run over 650,000 cipher variations. Eventually, it could crack open the cipher’s construction specifically.
Eyke, however, attributes their success to a true team effort. “And I am so happy to be a part of it.”
However, the Zodiac Killer remains unidentified, and the FBI is still looking for this serial killer.
Source: Interesting Engineering
The Zodiac Killer’s cipher is finally solved after 51 years