Password protection of a single page with registration

Hi, I wonder if anyone can tip me on how to protect a page with password with a registration for it, can’t use global registration (which I have OFF) as I need to password protect only ONE page and not the WHOLE Blog. And thinking to apply different password for each registration that apply to access the page.
I found a PHP script but I think it would be tricky to use it with WP as WP is not single HTML or CSS pages..

Thanks!