How can I make my blog private? [closed]

I finally found something (I think): Network Privacy is currently in version 0.1.4 but looks just about right.

When installed, there’s a new Privacy setting screen where I can choose, e.g.

I would like my site to be visible only to Site contributors.

Given that new users automatically get the permission level Subscribers when they sign up, this setting allows me to select among the registered users and promote them to the Contributor level.

When I visit the site without being logged in, or logged in as a Subscriber (lowest level of registered users) then I am redirected to the login screen that also includes the message:

[My site] can be viewed only by contributors and above.
Subscribers and logged-out users are not able to view this site.