In the 1960s, Northern California was terrorized by a serial killer, who dubbed themselves the Zodiac Killer. Over the span of a year, they sent a total of four coded letters to the San Francisco Chronicle, and up until Dec. 2020, only one of them had been cracked. One of the  letters, known as the 340 Cipher, was sent to the San Francisco Chronicle over fifty years ago in 1969 and was finally solved on Dec. 5, 2020. David Oranchak, a graduate of Virginia Tech, worked on the cipher for months alongside Sam Blake from Melbourne, Australia and Jarl Van Eycke from Belgium. Oranchak, who currently runs a YouTube channel and website dedicated to the Zodiac Killer has been working on the code for fourteen years, but was never able to crack it. 

    For over a year the Zodiac Killer tormented the communities of Northern California, killing a total of five people. The killer sent numerous messages to The San Francisco Chronicle; however, this message is only the second to be cracked. The first, called the 408 Cipher, was cracked in 1969 and provided little information other than, “I like killing because it is so much fun.” The 408 consisted mainly of figuring out which symbols represented which letters; however, the 340 was more complicated. The code has a diagonal alignment down the page, with the letter occasionally being shifted over a column which caused the cipher to go unsolved for 51 years. 

    In the letter, the killer references a TV show where the supposed killer called in. The killer writes, “That wasnt (sic) me on TV.” The Zodiac goes on to say, “I am not afraid of the gas chamber” and that the killer now has “enough slaves to work for [him] where everyone else has nothing when they reach paradice (sic).” 

    Oranchak, Blake, and Van Eycke worked for over eight months and ran over 650,000 different readings of the cipher before cracking it. Blake is quoted in the San Francisco Chronicle saying, “we now understand why it resisted attacks for so long. The reading direction through the cipher is so obscure that the only way it can be found was with a massive search through many candidates using sophisticated software which can efficiently solve homophonic substitution ciphers.” 

    Blake, Oranchack, and Van Eycke told the San Francisco Chronicle that they would like to dedicate their work to the victims, families, and their descendants saying, “We hope this is a stepping stone towards finding justice for these people.” 

Fagan, Kevin. “Zodiac ‘340 Cipher’ Cracked by Code Experts 51 Years after It Was Sent to the S.F. Chronicle.” , 12 Dec. 2020, https://www.sfchronicle.com/crime/article/Zodiac-340-cypher-cracked-by-code-expert-51-years-15794943.php. Accessed Mar. 1, 2021. 

Levenson, Michael. “51 Years Later, Coded Message Attributed to Zodiac Killer Has Been Solved, F.B.I. Says.” , 12 Dec. 2020. , https://www.nytimes.com/2020/12/11/us/zodiac-killer-code-broken.html   . Accessed Mar. 1, 2021.