Hi, folks.  I've been worried for a while about the fact that my notmuch
mua (notmuch-emacs) does not automatically encrypt replies to encrypted
messages.  Recently my fears came true when I accidentally sent in the
clear a reply to an encrypted message that include a full quote of the
original encrypted text.  This is obviously not ok, to the extent that I
would like to now consider this a UI bug in notmuch-emacs.

The question is how do we solve this problem.  The tricky bit is that
notmuch-emacs uses message-mode to compose and send messages, and mml to
handle signing and encrypting, but uses the binary "reply" command to
generate reply bodies.  message-mode therefore does not know if the
original message was encrypted or not.

One proposal would be to add a switch to the reply command that would
insert the mml "signencrypt" header [0] to the top of reply bodies if
the message being replied to was encrypted.  Something like
"--mml-encrypt" or something like that.  It's a fix targeted to a
particular work flow/setup, but it might cover enough use cases to make
it still be worthwhile.

What do people think?  Any other ideas for solving this issue?  I note
that there are other emacs tricks for dealing with encrypting messages
[1], but none that I have found would solve this particular situation.

jamie.

[0] https://www.gnu.org/software/emacs/manual/html_node/mh-e/Sending-PGP.html
[1] http://www.emacswiki.org/emacs/DefaultEncrypt