Looking for a login plugin that does this…

Hi. I have looked around the internet the past two days and can’t seem to find a plugin that does the following:

1. Allows you to make a page that has to be logged in to to access.
2. Has site users log in to access that page with their own username and password (that they currently have as they are users of the site)
3. Allows me to know who logged in to the page.

Would help a great deal if this plugin was free.

Does anyone know of a plugin like this?

I appreciate you reading.