It is true that Robert Graysmith believes he has cracked the cipher. What the movie misses is that he revisited this solution at least once, and he’s not the only person who has tried to solve this particular cipher. The one in question, known as cipher 340, was submitted to the San Francisco Chronicle on November 8, 1969. Its name comes from the number of characters in the cipher, although the note also contained the phrase “Des July Aug Sept Oct = 7”, which presumably refers to the months of the Zodiac’s crimes.
Graysmith’s modified cipher solution as documented ZodiacKillerFacts.com, was included in his first book, The Zodiac. The original version is what brought him fame, as shown in the film. Both decisions make the cipher look like a poem about Chronicle columnist Herb Kahn, but Graysmith’s findings were not accepted by the FBI.
The last attempt to solve the cipher was made in 2020. Washington Postwhen a group of codebreakers from around the world used a computer program to break the code. The decision was attributed to David Oranczak, Jarl Van Eyck and Sam Blake, which was verified by the FBI. The newspaper “New York Times. Oranczak, site manager ZodiacKillerCiphers.comworked on solving the code for 14 years.