[PATCH] Encrypt replies to encrypted messages by default.

[Karl Fogel]

I'd like to apply the patch below, which causes replies to encrypted
messages to also be encrypted by default, at least in Gnus.

Reasoning: 

As a failure mode, it's much better to accidentally encrypt than to
accidentally *not* encrypt -- especially with email, where the reply may
quote parts of the original mail (which was sent encrypted, thus raising
the likelihood that quoted excerpts would be of a sensitive nature).

It actually happened to me recently: I accidentally sent a reply in
plaintext, quoting parts of a rather sensitive mail, because I'd
unconsciously expected Emacs to automatically encrypt the reply.  That
incident started me looking for some way to control this behavior.  I
was glad to find `gnus-message-replyencrypt' (I thought I was going to
have to implement it), but surprised it was not set to `t' by default.

Note the same logic does not apply to `gnus-message-replysign', so I
haven't changed that variable's default in this patch.

Does anyone think this is a bad idea?  If we agree it's good, is it
enough to commit it to Emacs, or should I also send it to a separate
Gnus list?

-Karl

  === modified file 'lisp/gnus/gnus-msg.el'
  --- lisp/gnus/gnus-msg.el     2010-12-02 22:21:31 +0000
  +++ lisp/gnus/gnus-msg.el     2011-01-02 21:27:04 +0000
  @@ -244,7 +244,7 @@
     :type 'boolean)
   
   (defcustom gnus-message-replyencrypt
  -  nil
  +  t
     "Automatically encrypt replies to encrypted messages.
   See also the `mml-default-encrypt-method' variable."
     :group 'gnus-message
  
  === modified file 'lisp/gnus/ChangeLog'
  --- lisp/gnus/ChangeLog       2010-12-27 09:46:02 +0000
  +++ lisp/gnus/ChangeLog       2011-01-02 21:27:42 +0000
  @@ -1,3 +1,7 @@
  +2011-01-02  Karl Fogel  <address@hidden>
  +
  +     * gnus-msg.el (gnus-message-replyencrypt): Default to `t'.
  +
   2010-12-27  Daiki Ueno  <address@hidden>
   
        * mml2015.el (mml2015-epg-sign, mml2015-epg-encrypt): Take care the