Charlemagne, one of the great rulers of the Middle Ages, was instrumental in the reestablishment of formal education in the West.
This font was inspired by the notion that he felt the need to protect his communications from people with the ability to read; a rare skill then. Did he really command such a script to exist? He did instigate the development Carolingian minuscule script. Here are two different systems that are both attributed to him.
Does it provide any real security? No, but it is fun to think about how such a system might have been used.