Four-Square Cipher

A polygraphic substitution cipher (Delastelle) that encrypts letter pairs using two keyed 5x5 grids alongside two standard alphabet grids.

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Plaintext / Input Message

Cryptographic Key / Shift

Auto Compute

Workspace Presets

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Preset nameSave key with preset — disabled by default. Stored keys remain readable to anyone with access to this browser profile.

Saved presets for this cipher

Output Result

No output

Imported traces are validated and replayed locally. They never run a cipher operation automatically.