Bifid cipher is a tomographic cipher that uses coordinates of letters and mixes them in order to get new coordinates.
It combines the Polybius square with transposition to encrypt a message in a way that makes if difficult to decode without knowing the secret.
With bifid cipher each letter in the ciphertext message is dependent upon two letters from the plaintext message, thus making frequency analysis difficult. It was invented by a Frenchman, Felix Delastelle in 1901. Felix also invented other ciphers like trifid cipher and four square cipher.
Use the above bifid cipher decoder and translator to encrypt/decrypt simple messages.