How do I manage read write protection individually for each content item

Hi,

I am considering to use drupal for a small community portal. I want to have content items which are visible to everybody, and I want to have content Items which should only be visible to members and are thus private.

Is there a way to add a public/private checkbox to every content item or something similar?

I don't even need a complex user-group system, only a flag to toggle private/public

Drupal is amazing, but useless to me, if there is no option to achieve this or something similar. :(

regards,