Cryptography is the art of hiding information; before the modern era this was synonymous with encryption, the rendering of information from a legible state to an unreadable one.
With the recent exposing of a secret Russian spy ring in the U.S. (still using, it seems, Rocky & Bullwinkle techniques) there has been a fresh round of popular interest in steganography as well. You might recall the unconfirmed speculations that embedded within Ebay images were secret messages to Al-Qaeda operatives.
Deleuze & Guattari, in A Thousand Plateaus, state that overcoding is the expression of capitalism par excellence. It is the parsing of code and overlaying of more coding that gives capital it’s quasi-magical powers to makes all objects commensurable with all other objects. I like how Paul D. Miller (aka DJ Spooky that Subliminal Kid) approached the term (from the webtake of his book Rhythm Science):
“Encoding. What comes to mind when you say the word? Whether its written or spoken, several meanings come to mind and in turn lead you down other paths of meaning — no fixed points come into perspective, no key opens the cryptographic realms of the word to penetration. One simply uses the word to refer to a process.”