Is it possible to restrict access to an asset to logged in users? i.e. is there a type of loginRequired functionality for assets? 

Or even better - can I restrict access to a single group, or a require a certain permission? 

In the "permissions" tab for users/groups I can only give access to uploading/deleting assets.
There is two similar plugins that look's like it might do the job (I have tested neither).


Internal Assets
MemberAssets