Well I guess it comes down to how important you think the metadata is. In reponse to your edit, if you are storing everything client side than POP works and is considerably simpler. Heck you could even just do local delivery.
The idea for IMAP with encrypted mail parts would be to allow multiple clients to access a remote mail store where the remote mail store could not read any of the stored email or its metadata even if it wanted to.
You'd also want your MTA to reject mail not sent over TLS. No matter what you do though if the remote server is compromised -- technically or legally -- your future emails are subject to capture.
> You'd also want your MTA to reject mail not sent over TLS. No matter what you do though if the remote server is compromised -- technically or legally -- your future emails are subject to capture.
agree & agree. Overall, the email protocol is fucked either way. :) As of now, I'm looking into, e.g. Pond [1]. Of course convincing people to just go ahead and move to something else is kind of quixotic / sisyphean; though it might be possible for a small circle of acquaintances where encryption is actually critical.
The idea for IMAP with encrypted mail parts would be to allow multiple clients to access a remote mail store where the remote mail store could not read any of the stored email or its metadata even if it wanted to.
You'd also want your MTA to reject mail not sent over TLS. No matter what you do though if the remote server is compromised -- technically or legally -- your future emails are subject to capture.