Data storing software (mediawiki, ..)


I need a simple data storing software, which would basically have the same functionality as mediawiki - will allow users to publish, edit content and it would only allow registered users to access the content.

Does mediawiki allows that - couldn’t find info anywhere about that?
If not, do you know of any similar software (preferably php) or service?

Thanks for help

Are you talking about large amounts of content (ex. several megabytes), or just the ability for content like articles to require a login?