In 1499, Johannes Trithemius, a German scholar and advisor to Emperor Maximilian, sent a letter to his friend Arnold Bostius regarding Steganographia, a new book he was working on. The letter described the work as involving methods to communicate across great distances and ways of expressing one’s thoughts without using words or signs of any sorts. By the time the letter arrived, Bostius had died, and his colleagues, alarmed by the letter’s contents, made it public, calling Trithemius an occultist and employer of demons.
On the surface, the book indeed appears to be a work on magic. It lists demonological names, invocations and ways to use spirits to send secret messages. However, as was later learned upon closer examination, it also contains hidden sophisticated ciphers—a vast display of cryptographic techniques…
