Pretty Good Printing?
I've set up one of my clients with PGP, using the plug-in for Microsoft Outlook. This is working well. I have progarams which generate and encrypt message, drop them into a mail, and send them off. The human who receives them double-clicks on the mail, enters their passphrase, and there's the text.

All was working well, until today the human in question attempted to print the message. "Printing of a PGP decrypted or verified message is not supported". Oh dear.

I agree that sending the message off to the printer may not be good to start with, network printing protocols are almost invariably sent in-the-clear. However there is a real and genuine business need to have these documents printed.

Of course, it doesn't help that I use mutt and GPG for my mail. For me, it all "just works".