Quoth Thomas Shaddack <shaddack@ns.arachne.cz>

Obvious lesson: Steganography tool authors, your programs should use the worm/HIV trick of changing their signatures with every invocation. Much harder for the forensic fedz to recognize your tools. (As suspicious, of course).

It should be enough to do that at the installation time. The adversary in this model gets to analyze the file only once, and we want to make sure that nobody tampered with the file as a protection against other, more "active" threat models. What we want is to have a file and its hash, so we can make sure the file content is unchanged, but the hash has to be as globally-unique as possible.

The NIST CDROM also doesn't seem to include source code amongst its sigs, so if you compile yourself, you may avoid their easy glance.

A cool thing for this purpose could be a patch for gcc to produce unique code every time, perhaps using some of the polymorphic methods used by viruses. Just adding a chunk of data to make the hash unique will work against the current generation of the described tools. But we should plan to the future, what moves the adversary can do to counter this step. -------- Dear TS: you have very good ideas.