Bifid Cipher

Polybius-based fractionating cipher (5×5 grid).

Keyword (optional) Preset Encrypt Decrypt

Text

Output

Show Polybius key grid (I/J merged)

 A    B    C    D    E 
 F    G    H   I/J   K 
 L    M    N    O    P 
 Q    R    S    T    U 
 V    W    X    Y    Z

About this tool

Each letter's row and column coordinates are interleaved, then re-paired into ciphertext. Keyword optionally seeds the grid (I/J merged).