Steganography is a method of hiding information inside another message or physical object so that the information is not evident to the casual observer. The first use of the term was in 1499 in a paper on cryptography disguised as a book on magic. I wrote about steganography in The Business Espionage Report and have seen messages hidden as code in tufts of grass in a scetch of a mission landscape in California.
   In steganography a secret message appears to be part of some other image or cover text. The secret message does not attract attention. Cryptography protects the contents of a message but attracts attention, steganography conceals the fact that a secret message is being sent.
   Steganography coding may be inserted inside a document file, image file, or other program. Large files are ideal because of their size. A sender might start with an ordinary image file and adjust the color of every hundredth pixel to mean a letter in the alphabet. Someone who is not looking for it won’t notice the change. Steganography was in use in Greece in 440 BC and is still in use today, at least in training. Old methods are often overlooked in a digital setting.