Arthur Pemberton wrote:
>
> A follow up question which I haven't yet understood from Googling,  what
> happens when my GPG signed email gets sent to my prof. who used Outlook?

He'll see a message, either with an inline PGP signature, or an
attachment (depending on your client configuration), but won't have any
indication that the signature is valid.  It's just some extra data in
the message.  He'd have to install a PGP plugin for Outlook, and get
your key's fingerprint from you in order to validate signed messages.

This is why I advocate SMIME: more people already have the software to
validate your messages.