caching of passphrases for symmetrically encrypted files

caching of passphrases for symmetrically encrypted files

[Jim Gomi]

Since I upgraded to emacs 25.1.1 under Fedora 24, the caching of
passphrases for symmetrically encrypted files  has stopped working.

According to the documentation, 
https://www.gnu.org/software/emacs/manual/html_mono/epa.html#Caching-Pa
ssphrases
I can either use GnuPG 1.4, or configure gpg-agent. But I cannot get
either of these to work.

1) Using GnuPG 2.1.13
I tried adding this to ~/.gnupg/gpg-agent.conf:

allow-emacs-pinentry

but I am still asked to retype the passphrase twice when saving the
file.
Is there something else I should do?


2) Using GnuPG 1.4 
I tried adding this to my .emacs file:

(setq epg-gpg-program "/usr/bin/gpg")
(setenv "GPG_AGENT_INFO" nil)
(setq epa-file-cache-passphrase-for-symmetric-encryption t)

but it had no effect.
/usr/bin/gpg is the GnuPG 1.4 executable.

Re: caching of passphrases for symmetrically encrypted files

[Eli Zaretskii]

> From: Jim Gomi <gomi@mailup.net>
> Date: Sun, 16 Oct 2016 17:48:45 -0500
> 
> 
> Since I upgraded to emacs 25.1.1 under Fedora 24, the caching of
> passphrases for symmetrically encrypted files  has stopped working.
> 
> According to the documentation, 
> https://www.gnu.org/software/emacs/manual/html_mono/epa.html#Caching-Pa
> ssphrases
> I can either use GnuPG 1.4, or configure gpg-agent. But I cannot get
> either of these to work.
> 
> 1) Using GnuPG 2.1.13
> I tried adding this to ~/.gnupg/gpg-agent.conf:
> 
> allow-emacs-pinentry
> 
> but I am still asked to retype the passphrase twice when saving the
> file.
> Is there something else I should do?

See

  https://lists.gnu.org/archive/html/emacs-devel/2014-11/msg00421.html

for how to do this with GnuPG 2.x.

> 2) Using GnuPG 1.4 
> I tried adding this to my .emacs file:
> 
> (setq epg-gpg-program "/usr/bin/gpg")
> (setenv "GPG_AGENT_INFO" nil)
> (setq epa-file-cache-passphrase-for-symmetric-encryption t)
> 
> but it had no effect.
> /usr/bin/gpg is the GnuPG 1.4 executable.

AFAIU, you are customizing epg-gpg-program incorrectly.  See
bug#24229:

  https://debbugs.gnu.org/cgi/bugreport.cgi?bug=24229

Re: caching of passphrases for symmetrically encrypted files

[Jim Gomi]

On Mon, 2016-10-17 at 09:02 +0300, Eli Zaretskii wrote:
> See
>   https://lists.gnu.org/archive/html/emacs-devel/2014-11/msg00421.html
> 
> for how to do this with GnuPG 2.x.

Thank you for this information.
Following those instructions I added this to the 
(custom-set-variables   ... ) section in .emacs :

'(epg-gpg-program "gpg2")
'(epa-pinentry-mode (quote loopback))

There is no need to alter ~/.gnupg/gpg-agent.conf
because allow-loopback-pinentry is the default.

But still I am prompted twice for the passphrase when I save a
symmetrically encrypted file.


> AFAIU, you are customizing epg-gpg-program incorrectly.  See
> bug#24229:
>   https://debbugs.gnu.org/cgi/bugreport.cgi?bug=24229

Thank you for this useful reference.
To make this work I had to add this to the (custom-set-variables   ... ) 
section in .emacs :
 '(epg-gpg-program "gpg")
 '(epa-file-cache-passphrase-for-symmetric-encryption t)

This worked, but I would never have realized that from reading the
current documentation.

Where do I go to make suggestions about improving the documentation?

Re: caching of passphrases for symmetrically encrypted files

[Eli Zaretskii]

> From: Jim Gomi <gomi@mailup.net>
> Date: Tue, 18 Oct 2016 08:13:27 -0500
> 
> Where do I go to make suggestions about improving the documentation?

Please file a bug report using report-emacs-bug.

Thanks.