Hello there and welcome to the Wowza support forum.
You can serve players from your web site. You can do authentication through a Flash RTMP player or HTTPProvider. If you have already handled authentication in your web site, you can get HTTP cookies from the html container of a Flash RTMP client with Actionscript ExternalInterface API. Either way, you can pass credentials or token in NetConnection and handle server-side in onConnect. For example: