I don't know if this is a globally usable solution, but with a fair amount of detective work, we've determined the problem with some users being able to use Pine to read pgp/mime messages (kmail with crypto plugin) and other users not being able to use Pine is a function of the ~/.procmailrc file. It took a while figure out what the difference was between 'working pine' and 'non-working pine' since the answer wasn't directly related to pine, gpg, the pine filters, of the plugin itself. If ~/.procmailrc contains the same lines that Mutt uses for pgp/gpg messages, even with Mutt not installed, Pine with the pgp4pine display filter will process mail generated with Kmail using either the inline, or plugin means of encrypting messages. if ~/.procmailrc has the following, all seems to work fine:
:0 fw * ^Content-Type: multipart/encrypted | formail -i "Content-Type: text/plain; charset=US-ASCII" FWIW Charlie
