Polygraphic substitution cipher with 5×5 key matrix and digraph pairing rules.
Execution runs 100% locally inside the browser sandbox using HTML5 Canvas, Web Cryptography Subtle API, and Web Workers. Zero egress.
Zero network latency. Operates completely offline with zero dependencies on third-party backend servers or cloud services.
Built according to official RFC specifications, cryptographic test vectors, and enterprise-grade data transformation standards.
Type your secret keyphrase to generate the 5×5 Polybius cipher matrix.
Select Encrypt or Decrypt mode.
View the automatic digraph splitting and copy the transformed ciphertext or plaintext.
The Playfair cipher is the first practical digraph substitution cipher, invented by Charles Wheatstone in 1854 and championed by Lord Playfair for military encryption.
If two identical letters appear in the same digraph pair (e.g. 'LL'), a filler character 'X' is inserted between them (e.g. 'LX LO').
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