GnuPG：www.gnupg.org

RFC 2440：www.rfc-editor.org/rfc/rfc2440.txt

Philip Zimmermann：www.philzimmermann.com

Diceware密码短语主页：www.diceware.com

维基百科：密码短语文章：www.wikipedia.org/wiki/Passphrase

GnuPG HOWTOs：www.gnupg.org/documentation/howtos.html