Create Secure Download Portal on Server

GENERAL I have a number of free downloads on my website, but often want to provide secure (password-protected) downloads to clients and event attendees. At the moment, I am using MediaFire to secure those downloads, but it's just not professional enough. I have a Windows cloud server and would like to reconfigure the domain I use to host my downloads to be able to secure selected downloads. SPECIFICS - FRONT END If someone clicks an unsecure (freely available) download link, it will download directly, as it does now. If the download link is for a secured download, they will be brought to a branded page that asks them to enter the password, after which the download will start. For my most secure files (workshop follow up documentation, for instance), they will need to enter their email address and will only be able to download the file once. SPECIFICS - BACK END I would like an interface that allows me to: => Upload files => Specify whether the file is secure or not => Specify whether an email address will be required, and allowed emails => Specify the password => Specify whether the download expires (and the date) => Provide the download link (ensuring I get the syntax right) I also need to be able to see a list of all files available for download, including: => Whether they are secure or not => How many times they have been downloaded => Link to edit details => Mechanism to easily copy the download link => Delete files Obviously, the back end will require a password to access. DESIGN The front end just needs my company logo and one or two fields (password and sometimes email). The back end should be simple and clean. OTHER I would like the domain not to be searchable by search engines. I think it's a [login to view URL] file??? SERVER => Windows IIS => MS SQL => Also set up for PHP => FTP access IMPORTANT Please provide a non-canned response to this brief. I will not consider hiring any providers who do not address the specifics of this brief.