Dear SQ

I clipped this from the Internet. Maybe it's a start.

Bacon was known to have invented and used a "bilateral cipher" which
used two different typefaces in each message. Each set of five letters
in the printed text represented one letter in the coded message. Using
capital and lowercase letters, for example, "Aaaa" might stand for
"a," "aAaaa" might be "b," and "aaAaa" might be "c" ... on through
"aAaAA" as "x," "aaAAA" as "y," and "AAAAa" as "z."


In actual use, the cipher could be relatively subtle. The first line
of "Macbeth" - "When shall we three meet again?" - could be printed in
a combination of regular and italic letters to spell any five-letter
encoded name, such as "Elvis."