Bacon's cipher

The Baconian Cipher or Bacon's Cipher is a method of steganography (a method of hiding a secret message rather than technically a cipher) devised by Francis Bacon depending a person's ability to control how a text is written rather than its content.

The alphabet of the Baconian cipher:
a   AAAAA   g     AABBA   n    ABBAA   t     BAABA
b   AAAAB   h     AABBB   o    ABBAB   u-v   BAABB
c   AAABA   i-j   ABAAA   p    ABBBA   w     BABAA
d   AAABB   k     ABAAB   q    ABBBB   x     BABAB
e   AABAA   l     ABABA   r    BAAAA   y     BABBA
f   AABAB   m     ABABB   s    BAAAB   z     BABBB

To encode a message, a person writes the plain text message and then writes out the message using the five letter code. Over that five letter code, the person writes a false message which is five times as long as the plain text message, and each letter which corresponds to a 'b' is put in italics.

To decode the message, a person puts a 'b' underneath each italic letter and an 'a' under all the rest. Then the message is decoded using the known five letter code.

Any method of writing the message that allows two distinct representations for each character can be used for the Bacon Cipher although the above specifies plain and italic as an example. Because any sufficiently long message can be used to carry the encoding the secret message is effectively hidden in plain sight. The false message can be on any topic and thus distract a person seeking to find the message.

Shakespeare

Some people have suggested that the plays attributed to William Shakespeare were in fact written by Francis Bacon and that he signed his name, so to speak, by include a message in the Bacon Cipher he devised.

Hugh Black was the first person to apply Lord Bacon's cipher to the copy of the inscription. With the changing of one capital letter to lower case and counting two 'stacked' letters as one capital, he got a mixed up message that can be phonetically understood as "Francis Bacon wrote Shakespeare's plays." So far, this has been the most viable method of deciphering the inscription. Others have tried, but their methods were inconsistent.