X-Git-Url: http://git.chise.org/gitweb/?a=blobdiff_plain;f=README;h=a8fda71e91521b5572f53464a92440dc5492e1bf;hb=c165609a9c48703317640231336ce8fa9e2ee4e9;hp=dc36f88ff708e6fc12c560b6f1baba5b93b50dc2;hpb=454594f45d0e44017c676f55d5ec6e248547e346;p=elisp%2Fepg.git

diff --git a/README b/README
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--- a/README
+++ b/README
@@ -1,63 +1,55 @@
 * What's this?
 
-EasyPG is yet another GnuPG interface for Emacs.  It consists of two
-parts: transparent file encryption utility and easy-to-use 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
 
-** GNU Emacs 21.4 or later
+NOTE: EasyPG is neither a fork nor a re-implementation of Gnus/PGG.
 
-** 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
 
-** Transparent file encryption
+** Installation
 
-EasyPG provides transparent file encryption similar to crypt++,
-alpaca.el, hedgehog.  To try this feature, put (require 'epg-file)
-in your ~/.emacs.el and C-x C-f ~/test.txt.gpg.
+  $ ./configure
+  $ sudo make install
 
-** Using with Gnus/PGG
+Add the following line to your ~/.emacs
 
-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
+  (require 'epa-setup)
 
-(setq pgg-scheme 'epg)
+Then you can browse your keyring by `M-x epa-list-keys'.  In addition,
+you can do some cryptographic operations on dired.
 
-* Advantages over other competitors
+  M-x dired
+  (mark some files)
+  : e (or M-x epg-dired-do-encrypt)
+  (select recipients and click [OK])
 
-There are many competitors of EasyPG such as Mailcrypt, PGG, gpg.el,
-etc.  EasyPG has some advantages over them.
+* Security consideration
 
-** EasyPG avoides potential security flaws of Emacs.
+** Passphrase may leak to a temporary file.
 
-*** `call-process-region' writes data in region to temporary files.
+`call-process-region' writes data in region to a temporary file.
+The EasyPG Library does not use `call-process-region' to communicate with a gpg
+subprocess.
 
-`call-process-region' writes data in region to temporary files.  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 passphrase safely.
 
-*** There is no way to clear strings safely.
-
-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.  It is recommended that as
-soon as you are done with passphrase you should clear it manually.
-However, PGG and gpg.el can keep passphrase strings in cache for a
-while and this behavior is their default!
-
-** 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.
+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.