Need a freelancer for making a website view-able from only authorized computers

Requirements: A web site must only work when being viewed from specific machines.

Limitations:
It is not enough to limit the webserver to specific IP addresses as the machines may be behind a NAT or otherwise obfuscated. A software may be installed on the machine to authenticate against the web server.

Prefered language usage on web server side is .NET / WebAPI. On client machine, there is no strong preference.

A complete system will provide a Asp.NET/WebAPI server application, a client application, and a simple website demonstrating successful usage.