Password Protecting a Custom Template Page

I have been searching all over the place for an answer to this question and cannot find it so I have resorted to making my own post in hopes that someone can just give me a direct answer.

I am trying to password protect a page with a custom page template that is pulling in posts from “category 5”.

Nothing I have done seems to be working!

I have resorted to using a silly Javascript password protector for now, but would really prefer using the built-in “Visibility” function.

Thanks in advance.