What the Zodiac Killer Cipher Said in the Recently Decrypted 340 Cipher
The Zodiac Killer cipher that drew the most attention in recent years was the 340-character cipher, a substitution code used by the Zodiac in a letter postmarked November 8, 1969, and sent to the San Francisco Chronicle. In December 2020, a team of amateur codebreakers led by David Oranchak, Sam Blake, and Jarl Van Eycke announced they had fully broken the 340 cipher using custom software and crowd-sourced computing power. The decrypted message reads, "I like killing people because it is so much fun it is more fun than killing wild game in the forrest because man is the most dangerouest anamal of all to kill something gives me the most thrills it is even better than getting your rocks off with a girl the best part of it is thae when I die I will be reborn in paradice and all the I have killed will become my slaves I will not give you my name because you will try to slow down or atop my collectiion of slaves for my afterlife ebeorietemethhpiti". The FBI confirmed the decryption and released the original scanned letters, noting that the message did not reveal the killer's identity or location.
The 340 cipher had remained unsolved for 51 years before the breakthrough, making it one of the most famous unsolved codes in criminal history. The Zodiac claimed credit for 37 murders in Northern California between 1968 and 1969, though law enforcement confirmed only 5 deaths directly linked to the killer. The cipher used a homophonic substitution system, meaning multiple symbols represented the same letter to foil frequency analysis. The decoded text shows the Zodiac's typical grandiose, boastful tone, mixing references to killing, slavery, and an afterlife with misspellings and garbled grammar. The decryption effort was widely covered by major outlets including Forbes, which detailed the technical methods used by the codebreaking team.
What Other Zodiac Ciphers Said and Their Current Status
The Zodiac Killer sent at least four other coded messages to newspapers and police during the 1960s and 1970s. The first cipher, known as Z408, was a 408-character substitution code that was solved by a team of codebreakers at the FBI within two weeks of the letter's arrival in July 1969. The decrypted Z408 message taunted police by saying, "I like killing people because it is so much fun it is more fun than killing wild game in the forrest because man is the most dangerouest anamal of all to kill something gives me the most thrills it is even better than getting your rocks off with a girl". The second cipher, Z340, was the one broken in 2020. The third cipher, Z13, consisted of only 13 characters and has never been solved. The fourth, Z32, contained 32 characters and also remains unsolved.
The FBI's Cryptanalysis and Racketeering Records Section has maintained that the remaining unsolved ciphers may contain clues to the Zodiac's identity but have not yielded any actionable leads. In 2021, the FBI released a new batch of Zodiac documents, including original letters and cipher pages, as part of a routine records review. The San Francisco Police Department and the Vallejo Police Department continue to list the Zodiac case as open, though no new arrests have been made. The case has inspired countless books, documentaries, and amateur investigations, with many researchers using modern computational tools to re-examine the unsolved ciphers. The Zodiac's ciphers remain a benchmark in the field of cryptography and criminal investigation, often cited in discussions of unsolved codes and cold cases.