Bacon's cipher

Bacon's cipher, also called the Baconian cipher, is a method of steganographic message encoding devised by Francis Bacon in 1605. Steganography conceals a message in the presentation of a text rather than in its content, so a reader who does not know to look for a hidden message sees only ordinary writing. Baconian ciphers are categorized as both a substitution cipher, when the code is written in plain form, and a concealment cipher, when the code is carried by the use of two different typefaces. This dual classification shows how one scheme can be read either as a code that replaces letters with symbols or as a way of hiding that any code is present at all, which places the method between classical cryptography and steganography.