-*** 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.
+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.