STEGANOGRAPHY
The art of creating and transmitting hidden messages.
The dictionaries — those few that include it, for it’s an extremely uncommon word — say this has to do with cryptography. But those in the spy business make a careful distinction between the techniques of cryptography and steganography, although both are aspects of the art of secret communication. Cryptography is the technique of scrambling a message in a systematic way so that (hopefully) it can be read only by its intended recipient. Steganography, on the other hand, keeps the message secret by hiding the fact that it exists at all. So the microdot of the Cold War spy novels — in which a document is photographically reduced to the size of a pinhead and stuck to an otherwise innocuous typescript — is an example of steganography. Invisible ink is another example. You can, of course, combine the two techniques if you believe in the braces-and-belt approach to life. Steganography derives from the Greek steganos, hidden or covered, plus graphein, to write. Someone who uses this technique is a steganographer.
