bug#20621: Encrypted files auto-saved in plain text during remote edit

[Nick Helm]

When using Tramp and EPA to edit an encrypted file on a remote machine, Emacs
auto-saves the file in unencrypted plain text.

>From Emacs -Q do:

C-x C-f 

Enter: /ssh:<user>@<host>:/path/to/encrypted/file.gpg

Enter: <user_password>

Enter: <symmetric_encryption_pass_phrase>

Edit file.gpg sufficiently to initiate auto-save

New file /path/to/encrypted/#_assh_buser@host_b_apath_ato_aencrypted_afile.gpg#
is saved in plain text on the remote machine (or default auto-save location).





In GNU Emacs 24.5.1 (x86_64-apple-darwin13.4.0, NS apple-appkit-1265.21)
 of 2015-04-11 on builder10-9.porkrind.org
Windowing system distributor `Apple', version 10.3.1347
Configured using:
 `configure --with-ns '--enable-locallisppath=/Library/Application
 Support/Emacs/${version}/site-lisp:/Library/Application
 Support/Emacs/site-lisp''

Important settings:
  value of $LANG: en_NZ.UTF-8
  locale-coding-system: utf-8-unix

Major mode: Lisp Interaction

Minor modes in effect:
  tooltip-mode: t
  electric-indent-mode: t
  mouse-wheel-mode: t
  tool-bar-mode: t
  menu-bar-mode: t
  file-name-shadow-mode: t
  global-font-lock-mode: t
  font-lock-mode: t
  blink-cursor-mode: t
  auto-composition-mode: t
  auto-encryption-mode: t
  auto-compression-mode: t
  line-number-mode: t
  transient-mark-mode: t

Recent messages:
For information about GNU Emacs and the GNU system, type C-h C-a.

Load-path shadows:
None found.

Features:
(shadow sort gnus-util mail-extr emacsbug message format-spec rfc822 mml
easymenu mml-sec mm-decode mm-bodies mm-encode mail-parse rfc2231
mailabbrev gmm-utils mailheader sendmail rfc2047 rfc2045 ietf-drums
mm-util help-fns mail-prsvr mail-utils time-date tooltip electric
uniquify ediff-hook vc-hooks lisp-float-type mwheel ns-win tool-bar dnd
fontset image regexp-opt fringe tabulated-list newcomment lisp-mode
prog-mode register page menu-bar rfn-eshadow timer select scroll-bar
mouse jit-lock font-lock syntax facemenu font-core frame cham georgian
utf-8-lang misc-lang vietnamese tibetan thai tai-viet lao korean
japanese hebrew greek romanian slovak czech european ethiopic indian
cyrillic chinese case-table epa-hook jka-cmpr-hook help simple abbrev
minibuffer nadvice loaddefs button faces cus-face macroexp files
text-properties overlay sha1 md5 base64 format env code-pages mule
custom widget hashtable-print-readable backquote make-network-process
cocoa ns multi-tty emacs)

Memory information:
((conses 16 71745 9990)
 (symbols 48 17206 0)
 (miscs 40 36 119)
 (strings 32 9772 4178)
 (string-bytes 1 257096)
 (vectors 16 8944)
 (vector-slots 8 372336 19181)
 (floats 8 53 218)
 (intervals 56 172 0)
 (buffers 960 11))