The problem is, unless you're very careful about distributions and such, you can easily clog the net with zillions of public-key-encryptions to alt.security.pgp.messages <grin>. But then again, I suppose it's not any more traffic than alt.sex.pictures.erotica.* generates. :)
It would be trivial to write a script to be put in your .login to automatically skim that newsgroup for anything encrypted with your public key. Hmmm...
Yes, Ed is right. Easy to spot messages intended for you. And the volumes involved in this "crypto classfieds" are not unreasonable.
4. How does the target of a message know where to look? Must he scan through all messages?
PGP will fail if signed with a key that it doesn't know about - that makes it easy... So, one doesn't need to decrypt all the messages (or try to), nor does one have to agree on a subject header or anything else. -- Ed Carp, N7EKG erc@apple.com 510/659-9560 anon-2133@twwells.com If you want magic, let go of your armor. Magic is so much stronger than steel! -- Richard Bach, "The Bridge Across Forever"