-*** There is no way to clear strings safely.
-To prevent passphrases from been stealing from cores, `read-passwd'
-function clears passphrase strings by `(fillarray string 0)'.
-However, it is not enough. Emacs does compaction of small strings in
-GC sweep phase. If GC happens before `fillarray', passphrase strings
-may be copied elsewhere in the memory. 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.