Can you crack the famous unsolved Zodiac 340-character cipher? The SF Chronicle published this cipher that was mailed to them by the Zodiac killer back in 1969. The first cipher he sent was solved by a high school teacher and his wife. The 340-character cipher below remains unsolved. Can you solve it? Try it! Click one of the cipher characters below and type the letter you want to substitute. I will look for some common words as you go and display them to the right. You can start with a randomized set of letters by clicking Randomize below. Or, click on one of the interesting decoders at the bottom of the page to see some interesting decodings of the cipher. Email me at doranchak at gmail dot com if you find anything interesting or have any comments/suggestions! (go back to (go back to new version of webtoy)

Please wait... Loading images... This should not take long...
Randomize | Reset
Interesting decoders: 1 (killing) | 2 (screaming) | 3 (robberies) | 4 (killedher) | 5 (zodiac) | 6 (murderer) | 7 (me murder banjo only) | 8 (got followed) | 9 (out in enjoy those thing as last inches) | 10 (zodiac shure me and is another vallejo about) | 11 (cipher are cages of the north about lies to insane) | 12 (toss blind all she eat bean because viv shall, killing, death, school, because, need, alive, slave, evils) | 13 (shall, cause, slaves, death, killing, because) | 14 (killing, slave, itis, because, school, death, shall, zodiac, paradice, collect) | 15 (halloween, killing, this, next, you, fun, die, zodiac, i am, i will) |

Technical caveat: I am assuming this is a simple monoalphabetic homophonic substitution cipher, and not something much harder like a transposition cipher or a polyalphabetic substitution cipher. The only reason I am assuming this is because the first 3-part cipher Zodiac sent to the newspaper was solved using homophonic substitution with a single alphabet.

(go back to