The 51-year unsolved Zodiac cipher- a lens on the cryptography of it all
Through his horrifically violent killing spree, the Zodiac killer created 4 ciphers. One of them was solved pretty much during the mass frenzy and panic of his reign of terror, and two remain unsolved to this day. One of them was just cracked. It took 51 years to decipher it.
The first cipher, later named Z408 for the 408 astronomical symbols it made use of, was very quickly solved by two schoolteachers (shoutout Donald and Bettye Harden).
Turns out it was simply a homophonic substitution cipher- a type of cipher that, simply speaking, involves replacing plaintext letters with a variety of homophones (ciphertext symbols). The other one, however- the Z340 cipher- took 51 years to crack. When they finally deciphered it, they found it to be a combination of homophonic substitution and a transposition cipher. It took over half a century and the prowess of modern day computers to find patterns and sequences that helped unravel it. (huger shoutout David Oranchak, Sam Blake, and Jowan Bergstrom). The two remaining ciphers- Z13 and Z32- remain notoriously unsolved because of how little content we have to go off of for both of them. There simply isnt enough material from the creator- a notorious, horrifically violent serial killer- to find out patterns. It's like how you can't find a pattern that's fourteen characters long if the material itself is like thirteen characters long. Sadly, we just don't have enough material to decipher it.
