Magic Signatures

Just wrote up a detailed Internet-Draft for the Salmon signature mechanism; since it's an outgrowth of the "magic security pixie dust" for Salmon I'm calling it Magic Signatures for now. It approximately matches the Magic Sig demo as well. Feedback welcomed!

(Updated: Just changed the text at http://www.salmon-protocol.org/salmon-protocol-summary as well, hopefully it makes a bit more sense now.)