X-Git-Url: http://git.chise.org/gitweb/?a=blobdiff_plain;f=README;h=9fdf6d79baa5ea1ab9c28e271c4829f29bc2bc0e;hb=93ea9862c87f44d904ed46c383f6f395afcb082d;hp=91cb7cd3c9a8c25195f9e77740c35bab526b3dd5;hpb=dc250f34d9659836694d49f782b57607b35a2276;p=elisp%2Fepg.git

diff --git a/README b/README
index 91cb7cd..9fdf6d7 100644
--- a/README
+++ b/README
@@ -1,75 +1,57 @@
 * 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
+- "The EasyPG Assistant" which provides basic GUI of GnuPG
+- "The EasyPG Library" which enables use of various features of GnuPG
+
+NOTE: EasyPG is neither a fork nor a re-implementation of Gnus/PGG.
 
-** GNU Emacs 21.4 or later, XEmacs 21.4 or later
+* Requirements
 
-** GnuPG 1.4.3 or later
+** GNU Emacs 21.4 or XEmacs 21.4
 
-** Gnus 5.10.8 or later (optional)
+** GnuPG 1.4.3
 
 * Quick start
 
 ** Installation
 
-$ ./configure
-$ sudo make install
-
-** Transparent file encryption utility
-
-EasyPG provides transparent file encryption utility similar to
-crypt++, alpaca.el, hedgehog.  To try this, add the following line to
-your ~/.emacs and C-x C-f ~/test.txt.gpg.
-
-(require 'epf)
-
-** 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
+Then you can browse your keyring by `M-x epa-list-keys'.  In addition,
+you can do some cryptographic operations on dired.
 
-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
-
-See "Security consideration" section.
-
-** GnuPG features are directly accessible from Emacs
-
-Other competitors provide only specific features of GnuPG since they
-still support PGP 2.*, 5.*, 6.*.  As the name indicates, EasyPG is
-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.
+  M-x dired
+  (mark some files)
+  : e (or M-x epg-dired-do-encrypt)
+  (select recipients and click [OK])
 
 * Security consideration
 
-** `call-process-region' writes data in region to a temporary file
+There are security pitfalls around Emacs.
+
+** Passphrase may leak 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
+The EasyPG Library does not use `call-process-region' to communicate with a gpg
 subprocess.
 
-** `(fillarray string 0)' is not enough to clear passphrases
+** Passphrase may be stolen from a core file.
 
-If Emacs crashed and dumps core, passphrase strings in memory are also
+If Emacs crashes and dumps core, Lisp 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.
+strings may be moved elsewhere in memory.  Therefore, passphrase
+caching in elisp is generally a bad idea.
 
+The EasyPG Library dares to disable passphrase caching.  Fortunately,
+there is more secure way to cache passphrases - use gpg-agent.  Elisp
+programs can set `epg-context-passphrase-callback' to cache user's
+passphrases, it is not recommended though.