Zend certified PHP/Magento developer

Using AD for authentication on my app?

We have a piece of software that runs as a Desktop Application, but requires login that goes through a web server.

For some users, the software is installed on a computer on a private network using Active Directory to manage OS users.

For users authenticated by AD, is there a way to bypass login in the Desktop Application through the webserver? Either by getting some tokens from AD to pass to the server, or having the server communicate with AD in some way. How would such a setup work? How should the server talk to AD to verify users? Can this also be done for web applications?