+* Security
+
+There are security pitfalls around Emacs.
+
+** Passphrase may leak to a temporary file.
+
+The function call-process-region writes data in region to a temporary
+file. If your PGP library used this function, your passphrases would
+leak to the filesystem.
+
+The EasyPG Library does not use call-process-region to communicate
+with a gpg subprocess.
+
+** Passphrase may be stolen from a core file.
+
+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) to avoid this risk. 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. Fortunately,
+there is more secure way to cache passphrases - use gpg-agent.
+
+* MUA Integration
+
+The EasyPG Library can be used in combination with MUA (Mail User
+Agents).
+
+** SEMI based MUA