Zodiac Cipher

The Zodiac Cipher refers to a set of ciphers used by the infamous Zodiac Killer in the late 1960s to send encrypted messages to newspapers and authorities in Northern California. These ciphers combine substitution, symbols, and, in some cases, simple transposition, creating challenging puzzles that drew widespread attention from cryptographers and amateur sleuths alike.

D’Agapeyeff Polybius Cipher

The D’Agapeyeff Polybius Cipher is a classical cipher named after Alexander D’Agapeyeff, who documented it in his 1939 book Codes and Ciphers. It is a type of Polybius (Square) Cipher that uses a 5×5 grid to convert letters into coordinates, typically numbers, which can then be transmitted or further encrypted. This method converts each letter of plaintext into a pair of digits representing its row and column in the grid.

Dorabella Cipher

The Dorabella Cipher is a mysterious and undeciphered cipher created by Edward Elgar, the famous English composer, in 1897. The cipher consists of 87 characters arranged in lines, using 24 unique symbols resembling semicircles rotated at different angles. Each symbol likely represents a letter, digraph, or some phonetic element, but the exact system remains unknown.

Cicada 3301

Cicada 3301 refers to a mysterious organization that gained notoriety for releasing a series of complex internet puzzles and cryptographic challenges starting in 2012. While not a cipher itself, the puzzles prominently feature cryptography, steganography, and classical cipher techniques, including substitution, transposition, and polyalphabetic ciphers. Participants are required to decode hidden messages, uncover metadata, and traverse a series of challenges that often combine digital and real-world clues.