The Zodiac Cipher is a symbolic substitution cipher that encodes plaintext letters into a set of distinct Zodiac-themed symbols. Unlike historical cryptograms associated with the Zodiac Killer, this version is purely thematic, using visual symbols inspired by astrological signs to represent letters of the alphabet. The cipher is typically monoalphabetic, meaning each plaintext letter maps to a single symbol, but it can be adapted with a keyword to shuffle the symbol order for added security.
To encrypt a message, each letter is replaced by its corresponding Zodiac symbol. For example, the word HELLO could map as H → ♆, E → ♃, L → ♊, L → ♊, O → ♍, producing the ciphertext ♆ ♃ ♊ ♊ ♍. Decryption requires the same symbol-to-letter mapping. This cipher is primarily used for puzzles, decorative encryption, or novelty encoding, combining visual appeal with classical substitution principles.