X-Git-Url: http://git.chise.org/gitweb/?a=blobdiff_plain;f=README;h=9fdf6d79baa5ea1ab9c28e271c4829f29bc2bc0e;hb=93ea9862c87f44d904ed46c383f6f395afcb082d;hp=b414c85e42a46c6c28b9b32148a80c87d096e32b;hpb=053e827352f5d8f7c356c695353e478cc112e088;p=elisp%2Fepg.git

diff --git a/README b/README
index b414c85..9fdf6d7 100644
--- a/README
+++ b/README
@@ -24,7 +24,8 @@ Add the following line to your ~/.emacs
 
   (require 'epa-setup)
 
-Then you can do some cryptographic operations on dired.
+Then you can browse your keyring by `M-x epa-list-keys'.  In addition,
+you can do some cryptographic operations on dired.
 
   M-x dired
   (mark some files)
@@ -33,21 +34,24 @@ Then you can do some cryptographic operations on dired.
 
 * 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 crashes 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.
+strings may be moved elsewhere in memory.  Therefore, passphrase
+caching in elisp is generally a bad idea.
 
-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.
+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.