Well unbreakable is relative to the computer power you have available to
you. If you want to have an extremely secure password use anything that is
20 characters or longer that contains uppercase, lowercase, numeric, and
special characters. A passwords such as " I only have 1 regret today! " is
a password that will not be broken probably at least this decade and it is
easy to remember since it what is called a pass phrase. For enterprises
there already is multi factor authentication such as smart cards. Regardless
of any password data is only safe it is physically secured or properly
encrypted. --- Steve