If you put the pgp or gpg e-mail encryption in front of Listserv, then Listserv will distribute the encrypted mail, and does not need to know the keys.
andrew
>>> "Kern, Thomas" <[log in to unmask]> 12/2/2010 8:36 AM >>>
I would hope that if Listserv had encryption capabilities, that the trigger for the processing would be the arrival of a message encrypted with Listserv's public key.