> > As Tatsuya wrote, epg--start function calls gpg2 program with setting
> > :coding property to raw-text, thus each argument should be encoded in
> > proper coding system by a caller.  The problem would occur on any OS
> > whose file name coding system was not utf-8.
> > 
> > For example, in case of epg-decrypt-file, following change is required
> > if we need to set :coding property to raw-text for ENCODING.
> > 
> > diff --git a/lisp/epg.el b/lisp/epg.el
> > index 7bec91f616d..59870761565 100644
> > --- a/lisp/epg.el
> > +++ b/lisp/epg.el
> > @@ -1468,7 +1468,10 @@ epg-decrypt-file
> >        (progn
> >  	(setf (epg-context-output-file context)
> >                (or plain (make-temp-file "epg-output")))
> > -	(epg-start-decrypt context (epg-make-data-from-file cipher))
> > +	(epg-start-decrypt context
> > +                           (epg-make-data-from-file
> > +                            (encode-coding-string
> > +                             cipher file-name-coding-system)))
> >  	(epg-wait-for-completion context)
> >  	(epg--check-error-for-decrypt context)
> >  	(unless plain
> 
> Thanks, but this doesn't look right to me.  The problem is likely in
> the fact that epg--start sets the encoding/decoding for the epg
> process to raw-text in a way that is too broad: it affects not only
> how we encode and decode text sent to and received from GnuPG, but
> also how its command-line arguments are encoded.  And that's not what
> we want.
> 
> So I think the right fix is in epg--start: instead of setting :coding
> as part of the make-process call, it should call
> set-process-coding-system _after_ the make-process call, so that
> raw-text will affect only the text we send and receive from gpg.
> 
> Can you try such a change and see if it fixes the problem?

I tested attached patch and confirmed the issue was resolved.  I'm not
sure that :coding setting for decoding in make-process can be removed.
I mean, I don't know whether Emacs can receive output from process
between make-process and set-process-coding-system.

-- 
Kazuhiro Ito