The new hubs on appearance editor has an additional new feature called Protected Hubs. This feature allows you to set your hub to be 'Public' or 'Protected'.
When you set the visibility of a hub to Protected, you allow the hub access only to a certain group of participants. The content you upload such as texts, images, videos etc does NOT prevent people from sharing the content with others. For example, participants WILL be able to save documents to their computers and forward them.
Note : It is possible to set the visibility of a hub as Protected, only at the point of creation.
How do I make my Hub 'Protected'?
While creating a new hub page on your site, you have the option to choose the visibility of the hub.
Projects can then be added to the hub either during creation or by going to the settings section of the project page.
Note : There is no option to change the visibility of a project while it is assigned to a Protected Hub.
An alternative here would be to reassign the project to another hub who's visibility is Public. To un-assign a project from a particular hub, go to Project settings and click on the 'x' button as shown below.
The visibility section shows the visibility of the hub along with the option to change the permalink of the Hub page.
Here you can assign participant groups and provide access to the Hub. Users who are part of this group can view and access all projects that are a part of this protected hub.