+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.