neas the Tactician is one of the more-famous Greeks, thanks in large part to his book, On the Defense of Fortified Places, which was the first instruction manual of its time for communications security. neas developed a steganography system whereby holes representing letters of the Greek alphabet were bored into a wooden disk. Yarn was then threaded through the holes in an order that would spell out the message. The decoder would simply reverse the process, writing the letters down backwards, to reconstruct the message.
Another method neas suggested was pinning tiny holes above or below specific letters in a document, thus spelling out the message. This steganographic system, called the newspaper code, was still used into the twentieth century.