* What's this?
-EasyPG is yet another GnuPG interface for Emacs. It consists of three
-parts: transparent file encryption utility, Gnus/PGG backend, and
-elisp library to interact with GnuPG.
+EasyPG is yet another GnuPG interface for Emacs. It consists of two parts:
-* Requirements
+epa.el - EasyPG Assistant, a basic GUI of GnuPG
+epg.el - the EasyPG library which interacts with GnuPG
-** GNU Emacs 21.4 or later
+NOTE: EasyPG is not a fork or a re-implementation of Gnus/PGG.
-** XEmacs 21.4 or later
+* Requirements
-** GnuPG 1.4.3 or later
+** GNU Emacs 21.4 or later, XEmacs 21.4 or later
-** Gnus 5.10.8 or later (optional)
+** GnuPG 1.4.3 or later
* Quick start
-** Transparent file encryption utility
-
-EasyPG provides transparent file encryption utility similar to
-crypt++, alpaca.el, hedgehog. To try this feature, add the following
-line to your ~/.emacs and C-x C-f ~/test.txt.gpg.
-
-(require 'epg-file)
+** Installation
-** Gnus/PGG backend
+$ ./configure
+$ sudo make install
-EasyPG provides an implementation of the backend interface of
-Gnus/PGG. To use EasyPG instead of pgg-gpg, install pgg-epg.el and
-add the following line to your ~/.gnus.
+Add the following line to your ~/.emacs
-(setq pgg-scheme 'epg)
+(require 'epa-setup)
* Advantages over other competitors
There are many competitors of EasyPG such as Mailcrypt, Gnus/PGG,
gpg.el, etc. EasyPG has some advantages over them.
-** EasyPG avoides potential security flaws of Emacs.
+** EasyPG avoides potential security flaws of Emacs
-*** `call-process-region' writes data in region to temporary files.
-
-`call-process-region' writes data in region to temporary files.
-Gnus/PGG and gpg.el use `call-process-region' to communicate with a
-gpg subprocess. Your passphrases leak to the filesystem!
-
-*** There is no way to clear strings safely.
-
-If Emacs crashed and dumps core, passphrase strings in memory are also
-dumped within the core file. `read-passwd' function clears passphrase
-strings by `(fillarray string 0)'. However, Emacs performs compaction
-in gc_sweep phase. If GC happens before `fillarray', passphrase
-strings may be moved elsewhere in memory. It is recommended that as
-soon as you are done with passphrase you should clear it manually.
-However, Gnus/PGG and gpg.el can keep passphrase strings in cache for
-a while and this behavior is their default!
+See "Security consideration" section.
** GnuPG features are directly accessible from Emacs
inspired by GPGME (GnuPG Made Easy), and the library interface is
close to GPGME. With EasyPG you can benefit from a lot of features of
GnuPG.
+
+* Security consideration
+
+** `call-process-region' writes data in region to a temporary file
+
+`call-process-region' writes data in region to a temporary file.
+EasyPG does *not* use `call-process-region' to communicate with a gpg
+subprocess.
+
+** `(fillarray string 0)' is not enough to clear passphrases
+
+If Emacs crashed and dumps core, passphrase strings in memory are also
+dumped within the core file. `read-passwd' function clears passphrase
+strings by `(fillarray string 0)'. However, Emacs performs compaction
+in gc_sweep phase. If GC happens before `fillarray', passphrase
+strings may be moved elsewhere in memory.
+
+Fortunately, there is gpg-agent to cache passphrases in more secure
+way, so the EasyPG library dares *not* to cache passphrase by itself.
+Elisp programs can set `epg-context-passphrase-callback' to cache
+user's passphrases.