Traditional steganography hides information in noisy spaces in data, such as the low bits of a sound sample. Permutation steganography hides information in the ordering of elements of a set. For examples, the orders of entries in a database, in which pre-arranged messages are sent, of the headers of a mail message, of books on a shelf, of cards in a deck, of people posing in a picture, of cars parked in a parking lot, or anything else. The technique is related to permutation numbering which is derived from work by Georg Cantor, D.N. Lehmer, and D.H. Lehmer.
This Python module provides the tools needed to implement steganography using permutations. Peter Wayner has a related Java applet. There's also Lisp code. And there's documentation from the code.
The code is under development, but close to an alpha release. EntropyBuffer.py might be useful for selecting numbers from unusual ranges.
The current release is pstego-0.2.tar.gz.