Amateur Codebreakers Finally Cracked The Zodiac Killer's Notorious Cipher

It has been 51 years since the Zodiac killer sent ciphers. The killer (believed to be male) has never been caught and some of his ciphers remain unsolved even today. However, the list of unsolved ciphers just got shorter. Over the weekend, the second cipher, Z-340, was solved. A combination of sophisticated technology and brute force hacking finally revealed the message.

In total, four ciphers were sent.

YouTube | David Oranchak

The first was relatively easy. It was dubbed Z-408 and was solved in 20 hours by a couple in San Francisco. Z-340 was the second cipher. It is shorter (340 characters vs. 408 characters) and used much more sophisticated encryption. The third is only 13 characters and remains unsolved. It supposedly reveals the Zodiac killer's identity. And the last cipher included a map, which pointed to the location of two of the murders.

David Oranchack, one of the three-person team that cracked the code, posted the solution on Youtube.

YouTube | David Oranchak

The fact that the cipher had not been solved was actually a clue. It implied that the characters must be scrambled as well as changed to symbols. Sam Blake recombined the symbols in a variety of ways to see if any different orders got them any closer to the message. Eventually, they got a message with some words. This break-through gave them clues about how the message was coded.

One clue that they were on the right track was a reference to a TV show.

YouTube | David Oranchak

Around the time the cipher was made, an imposter called into a TV show. The person claimed that they were the Zodiac Killer and that they were sick and should be put to death in the gas chamber. So, when the team decoded "gas chamber" in one of the recombinations, it gave them hope that they were on the right track.

The 340 character puzzle can be broken into three sections.

YouTube | David Oranchak

Each section is scrambled. The characters are rearranged into a diagonal pattern. To make things more difficult, the Zodiac killer also spelled some words backward and shifted the message in some sections by including some of the words from the end of the message at the beginning. It was a combination of problem-solving and trial and error that finally solved the puzzle.

When they finally solved the cipher, the team was in disbelief.

YouTube | David Oranchak

Oranchak told CNN:

"It was incredible. It was a big shock, I never really thought we'd find anything because I had grown so used to failure [...] When I first started, I used to get excited when I would see some words come through -- they were like false positives, phantoms. I had grown used to that. It was a long shot -- we didn't even really know if there was a message."

As excited as the team was to solve the mystery, they were disappointed that it did not contain any identifying information. Maybe someday we will crack Z-13 and see if it really contains the Zodiac Killer's identity.

h/t: Ars Technica h/t: YouTube