Every letter becomes a five-character sequence of just two symbols, a and b — 2⁵ = 32 combinations for a 24-letter alphabet (I/J and U/V share a form, as in Bacon's own day). Switch modes to encode a message or decode one back.
The hiding mechanism — in the demo above, plain letters represent "a" and bold italic letters represent "b" — this is exactly how Bacon's system worked in print, using two subtly different typefaces set side by side in ordinary-looking text. A reader unaware of the system sees only normal prose.
The Full Baconian Alphabet