Math

I'd like to describe a very simple scheme to publish messages in a such a way that you can deny you're publishing them. I call it "deniable plaintext", by reference to "deniable encryption", because no encryption or authentication is involved. Despite some search, I haven't found this scheme described in this specific of file sharing.

Scenario

In short, Alice takes the file F she wants to publish and a decoy ("chaff") file D, she's ready to admit publishing.