Beale Cipher

What is a Beale Cipher?

A Beale cipher (more precisely a book cipher) uses a shared text as a codebook. Each word in the text is assigned a sequential number starting at 1. To represent a letter, the sender picks any word whose first letter matches and writes down that word's number. Because many words can start with the same letter, the same plaintext letter can produce different cipher numbers each time — making frequency analysis much harder.

Historical note

The historical Beale Papers (1820s) used the Declaration of Independence as their codebook. Here we use Ray Bradbury's short story "A Sound of Thunder" as a tribute to the butterfly-effect theme of the saga.

To encode

1. Type your message in the Encode tab (letters A–Z; spaces are preserved as dashes).
2. Click Encode. For each letter the app picks one word number at random from all words starting with that letter.
3. The output numbers are your cipher text. Share them — plus the key text — with your recipient.

To decode

1. Paste the cipher numbers into the Decode tab.
2. Click Decode. The app looks up each number in the key text and reads the first letter of that word.
3. Numbers out of range or pointing to punctuation-only words show as ?.

Animation

After encoding or decoding, the result letters are loaded into the SWCharacter canvas. Press Start to scatter and spin them, then Assemble to call them home in formation.

Key-Text Index

The right panel shows which word numbers map to each letter. Up to 20 samples are shown per letter; use the full list to hand-craft ambiguous messages.