In 1969, the Zodiac Killer sent an encoded note to the San Francisco Chronicle. In 2020, someone finally cracked the code. And that someone was three people, with zero cryptography experience, who had met in an online true-crime forum. Kathryn Miles tells you how, and the result is a must for any puzzle fan.

Most experts, including the FBI’s crypto unit, agree that Oranchak and his team cracked the 340. Like the first cipher, it reveals a beguiling combination of high and low diction, spelling mistakes, and vague imaginings of immortality. Also like the first cipher, it lacks a hard clue as to the Zodiac’s identity.
But James Fitzgerald says that even the 340’s variations and mistakes hold valuable information for forensic linguists, including possible hints at the writer’s race, ethnicity, age, and gender.