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Known Plaintext / Crib Solver

Use expected words or coordinates to infer likely cipher keys, offsets, and solver tools.

A crib is a word or phrase you expect the plaintext to contain, like FINAL, CACHE, or the start of a coordinate such as N 40. Paste the ciphertext and one or more cribs, and the solver slides each crib across the text to work out which cipher family fits, the likely key, shift, or offset, decodes a preview, and ranks the results. This is a detective layer above the ciphers, so every result links straight to the matching tool, Multi Decoder, and the Cipher Identifier.

Separate multiple cribs with commas or new lines. Each one is tried independently.

Cipher families to try

Each crib is also tried against four cleanup variants of the ciphertext: original, spaces removed, letters only, and reversed. Harder ciphers like substitution and Playfair can be handed to a cloud solver from the matching result card.