Cipher methods Symbols
Stray (Walled City 99)
The Walled City 99 alphabet is the script of the post-human world of Stray (BlueTwelve Studio / Annapurna Interactive, 19 July 2022 on PS4/PS5/PC). The narrative adventure game follows an orange cat stranded in an isolated bunker-city, populated only by robot Companions — AI humanoids who took over after humanity disappeared.
Companions communicate in a distinct language, written in this alphabet: you can find it on bar signs (Momo’s, the Stray Lounge), vending machines, wall graffiti, and books the cat can interact with. Decoding the alphabet is part of the central puzzle resolution of the game: multiple achievements reward players who fully transliterate in-game inscriptions.
How does the alphabet work?
The cipher uses a monoalphabetic substitution: every letter of the plaintext is replaced by a glyph drawn from a fixed correspondence table. It is one of the oldest cryptographic techniques on record — already described in antiquity (Caesar cipher, ~50 BC) — and the most directly readable family for a beginner.
The table holds 26 glyphs for the 26 Latin letters (no dedicated digit glyphs). To encrypt, read the text letter by letter and replace each letter with its glyph.
Cryptographic strength: weak. Because every plaintext letter always maps to the same glyph, the cipher falls to a frequency analysis in a few dozen words (in both English and French, E remains the most common letter, an immediate entry point). Monoalphabetic substitutions are therefore used today for their decorative, playful or pedagogical value — not to protect real information.
Historical and modern usage
- Stray (2022) — Walled City signs, graffiti, books, vending machines.
- Stray community — used in fan art, cosplay, tattoos (especially of the robot B-12).
- Pedagogy — example of a cipher integrated into game mechanics (decoding = progress).
Related variants
- Standard Galactic — another video-game pop-culture alphabet (see our entry).
- Aurebesh — another decorative sci-fi alphabet (Star Wars, see our entry).
What are the weaknesses?
- Monoalphabetic substitution — immediate frequency analysis.
- Documented alphabet — public table on Stray Wiki and dCode from year 1 of the game.
- Monochrome glyphs — readable but no case/style variation.
The 26 glyphs
