Steganography

There was a post on slashdot about Steganography. Now I am not much of a slashdot reader, but chaos prevailed, and I was on slashdot. The concept is great. The ability to hide data within other data such as an image. There are a couple of algorithms available out there, but it seems none are mature enough for general usage.

There is a good article here, at least an article that rates high on google.
http://www.guillermito2.net/stegano/ideas.html

The guy makes a very good point that all data out there is not random, seems random, but in fact there is order to chaos. Encryption algorithms tend to go against the grain. Its like dumping a pink elephant in the middle of Time Square and asking what's out of the ordinary. Most encrypted files beckon for decryption. They sit out there in plain site with nothing hiding them but the encryption algorithm.

Encryption if very complicated, Steganography seems even more complicated. I am wondering if its possible to use the actual image as data; versus adding something to the image, or modifying part of the data stream like the header or certain insignificant bits. Given a file and an image, would it be possible to produce a mapping such that the file maps to the image, and given the image and the key its possible to produce the file. The key is obviously very complex and very specific to the file. The key is meaningless by itself, and so is the image. Of course, the weakness is that the key must be protected. The beautify is that there is no encrypted file sitting somewhere. Instead there are trillions of images sitting in the public domain. No algorithm defined, but it should be possible. For example, given a neural net, it is possible to get the correct result. The image is the outcome, the file is the inputs, the net then figures out the weights on the nodes to get the right result. The weights then make up the key, assuming that reverse is true, which I am not so sure.