For your eyes only...
Vanilla comes with built-in password protection for all public pages. You simply add a password (under 'Status & Visibility') when editing the page and visitors will be prompted for a password.
Passwords are remembered for subsequent visits within the same browsing session so visitors don't have to keep typing them in. Te remove the password protection, simply delete the password.
Click here to visit a password-protected page (the password is password).