I think the proposed scheme is a little top-heavy. What's wrong with clear text? When the Shah still governed Iran, the followers of Khomeini would smuggle his speeches into the country (in clear-text) on cassette tapes of Western popular music. I guess you could call this steganography --- so many ``legitimate'' copies of the tapes were pouring into the country, that the ``subversive'' ones were hard to find among them. I think the tapes actually held a few minutes' worth of the original music, to discourage those zealous customs agents who would actually listen to part of the tape to make sure it is authentic. Similar things existed in the Soviet Union, where they were known as ``Magnetizdat''. And, well, if the police have already gone to the length of confiscating your tapes and listening to them all to find the ones which contain Khomeini's speeches, they've also probably already got you on the train for the Gulag, no matter what they find.