As my wiki is public and freely accessible worldwide, sometimes there is a need of not publishing some content before a certain event (let's say, a certain date). Let's say, I would like to upload a few files and keep them secret, however, I would like the content to be accessible to some super user groups. If I right, there is an extension Hidden Pages, but, from what I remember, it's more like a hack, and I wouldn't like to hide pages or files, but just restrict the view access. An example scenario I currently thinking of is as follows:

• Create a restricted namespace
• Upload a file into that namespace (as far as I remember, this is not possible in MediaWiki, though)
• Do not link a file from elsewhere but a page that's in a restricted namespace as well, so it couldn't be leaked
• Once a file could be published, just move a file (or a page) to an unrestricted namespace.

Is it possible in MediaWiki somehow?

Thanks.