[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: gpg support

At Wed, 18 Dec 2013 23:55:12 +0100,
Neal H. Walfield wrote:
> 
> Hi,
> 
> What is the recommended way to use gpg under wl these days?

Hi,

I did some research a month ago or so on this topic, so I allow myself
to chime in here...

It was  not quite  easy to  get the  bits together  for me,  though in
general, many  things seem to  work well.  I  found three ways  to use
OpenPGP encryption from within wanderlust  using the GNU privacy guard
gpg in  the background (I  did not  research S/MIME, though)  and will
give a summary below.

For way 1) and 2) I was using  wl as in git commit
a8c38a3a68d9bf69381f4f4179d86a3ca1b07e92 of  Sun Sep 23  11:00:03 2012
+0200 on emacs-24.3, apel-10.7 flim-1.14.9, semi-1.14.6.

1) The wanderlust built-in way based  on stock semi-1.14.6

   WL has  C-c C-x v  (mime-edit-set-sign) for  signing and C-c  C-x h
   (mime-edit-set-encrypt)  for  encrypting.   It  generates  PGP/MIME
   messages  (which is  good). For  verification/decryption go  to the
   MIME header of the encrypted/signed part and press 'v'.
  
   This is based on pgg, the "glue for the various PGP implementations".
   As Eric Hetzner posted in 

   http://comments.gmane.org/gmane.mail.wanderlust.general/2811,

   a pgg  implementation comes  along with SEMI,  which is  faulty. He
   advises to use the built-in pgg  which comes along with emacs, just
   by erasing all things pgg* in the SEMI installation. I did this and
   I put

     (require 'pgg)
     (setq pgg-passphrase-cache-expiry 300)
     (setq pgg-decrypt-automatically t)
     (setq mime-setup-enable-pgp t) ; it is the default
     (setq pgg-default-scheme 'gpg) ; for composing
     (setq pgg-scheme 'gpg) ; for verify/decrypt
     (setq pgg-cache-passphrase t) ;
       
    into my .wl, and things started to work.
   Unfortunately (in emacs 24) pgg is in lisp/obsolete.

2) EasyPG/epa-mail, the EasyPG assistant
   
   EasyPG provides  epa-mail which creates PGP/INLINE  messages (which
   is not so good) and signatures. I  did not figure out how to get it
   to create PGP/MIME.

   You have the M-x commands
      epa-mail-encrypt
      epa-mail-decrypt
      epa-mail-sign
      epa-mail-verify
   and an epa-mail-mode with corresponding key bindings. You just convert
   your current buffer before sending the message.

   It seems to be completely independent of any email client, you just
   can take  a buffer containing  an RFC822 compliant mail  header and
   encrypt it etc.  There are  some reports referring to problems with
   MIME, though.

   For setting this up, I put 
   
      (require 'epa)
      (epa-file-enable)
      (setq epa-file-cache-passphrase-for-symmetric-encryption t)

   into my .emacs.
   In particular, this can coexist without any problems with 1).

3) The  wanderlust built-in way  based on SEMI-EPG by  Ito-san.  After
   reading his reaction to this thread,  before posting this, I gave a
   try to SEMI-EPG which  I took from github as of today  (and I did an
   update of  wanderlust as well...).   Moreover, I commented  out all
   things pgg I used to have for 1).

   This seems to be  a nice blend of 1) and 2): it  has the same UI as
   the stock  SEMI implementation, and  it creates PGP/MIME  (which is
   good). At  the same time  it uses the  EasyPG/epa backend as  in 2)
   which seems to survive in emacs.
   
   I wasn't able to test this in productive usage, though.

Summary so far:
   - OpenPGP encryption seems to be useable, once you have the information.
   - Stock SEMI creates PGP/MIME and uses pgg  which is obsolete in emacs 24
   - EasyPG alone which shall replace pgg creates only PGP/INLINE
   - SEMI-EPG by Kazuhiro Ito seems to be the right blend of both.

Questions:
   - What did I miss ?
   - Is there any plan to replace SEMI by SEMI-EPG ?
   - Is it reasonable to recommend 3) to everyone who is asking ?

Best regards
Jürgen

--
Jürgen Fuhrmann         Numerical Mathematics and Scientific Computing
            Weierstrass Institute for Applied Analysis and Stochastics
Mohrenstr.39 10117 Berlin   phone:+49 30 20372560  fax:+49 30 20372317
http://www.wias-berlin.de/~fuhrmann    juergen.fuhrmann@wias-berlin.de