Type your text and a keyword, and the tool encrypts it with the reciprocal Beaufort cipher — running it through again with the same keyword decrypts it.
Beaufort computes each ciphertext letter as C = (K − P) mod 26 instead of Vigenère's (P + K). This makes it reciprocal: applying the same keyword again decrypts the message.
Any keyword made of letters. It is repeated across the message; only alphabetic characters are enciphered, and non-letters pass through unchanged.
Not really — because Beaufort is reciprocal, encrypting the ciphertext with the same key restores the plaintext. The mode toggle is provided for clarity.