X-Git-Url: http://git.chise.org/gitweb/?a=blobdiff_plain;f=README;h=b438bd3330e83010f5e01ce59e33527d0b1ba665;hb=359180decf50389e8a5313a3fb04c88a6a93f69e;hp=460448360b4d19a5309c12b82cc7454c91c0e672;hpb=ae41538facb2b0d2f1ca1a3ee40d4610734f4683;p=elisp%2Fepg.git

diff --git a/README b/README
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 * 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
+
+NOTE: EasyPG is neither a fork nor a re-implementation of Gnus/PGG.
 
-** GNU Emacs 21.4 or later
+* Requirements
 
-** XEmacs 21.4 or later
+** GNU Emacs 21.4 or XEmacs 21.4
 
-** GnuPG 1.4.3 or later
+** GnuPG 1.4.3
 
 * Quick start
 
-(0) Put (require 'epg-file) in your ~/.emacs.el
+** Installation
+
+  $ ./configure
+  $ sudo make install
 
-(1) Restart emacs
+Add the following line to your ~/.emacs
 
-(2) C-x C-f ~/test.gpg
+  (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, PGG, gpg.el,
-etc.  EasyPG has some advantages over them.
+  M-x dired
+  (mark some files)
+  : e (or M-x epg-dired-do-encrypt)
+  (select recipients and click [OK])
 
-** EasyPG avoides potential security flaws of Emacs.
+* Security consideration
 
-*** `call-process-region' writes data in region to a temporary file.
+** `call-process-region' writes data in region to a temporary file
 
-PGG and gpg.el use `call-process-region' to communicate with a gpg
-subprocess.  Your passphrases may leak to the filesystem.
+`call-process-region' writes data in region to a temporary file.
+EasyPG does *not* use `call-process-region' to communicate with a gpg
+subprocess.
 
-*** There is no way to clear strings safely.
+** `(fillarray string 0)' is not enough to clear passphrases
 
-If Emacs crashed and dumps core, passphrase strings in memory are also
-dumped with the core file.  `read-passwd' function clears passphrase
-strings by `(fillarray string 0)'.  However, it is not perfect.  Emacs
-does compaction of small strings in gc_sweep phase.  If GC happens
-before `fillarray', passphrase strings may be copied elsewhere in
-memory.  So, it is recommended that if you are done with passphrase
-you should clear it manually.  However, PGG and gpg.el enables
-passphrase caching by default.
+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.  Therefore, passphrase
+caching in Elisp is generally a bad idea.  The EasyPG Library dares to
+disable passphrase caching.
 
-** Most GnuPG features are accessible from Emacs
+Fortunately, there is more secure way to cache passphrases - use
+gpg-agent.
 
-As the name indicates, EasyPG is inspired by GPGME (GnuPG Made Easy),
-and the library interface is close to GPGME.
+Elisp programs can set `epg-context-passphrase-callback' to cache
+user's passphrases, it is not recommended though.