It would be neat if you could quote people and prove that they signed the particular paragraph quoted without supplying the entire text. Is there a way to do this?
Yes. To do it using standard proggies, hash each of your paragraphs and put the results in a PGP-signed message. Quoter provides signature and signed hashes. Reader hashes your quoted paragraph and checks the signed message to see if it was one of the original paragraphs. So simple I can do it. :) [Disclaimer: I think.] A more cool-sounding solution would be to concatenate those hashes and sign them (not a hash of them) as one packet. Since RSA sigs are secret-key decryptions (right?), the reader can re-encrypt it and check any individual hash. Not more secure, though, and it takes a lot of processor time. No idea how to do it with bit-level granularity.
(It seems impossible, but so does mental poker.)
Mental poker? Easy.
A crude approach would be to sign every paragraph or line separately, but that's obviously inelegant.
Allows you a tad too much freedom with their quotes, too...
Monty Cantsin Editor in Chief Smile Magazine http://www.neoism.org/squares/smile_index.html http://www.neoism.org/squares/cantsin_10.htm
--------------------------------------------------------------------------- Randall Farmer rfarmer@hiwaay.net http://hiwaay.net/~rfarmer