IFrame Windows Authentication to On-Premises

Hi

I am migrating an on-promises 2007 environment to SharePoint 2013 Online.

The 2007 farm has many applications that use windows authentication, in SharePoint webparts, iFrames and  Reporting Services webparts.

We would like to leave the legacy applications on-premises, but still host the applications in SharePoint.

We will rewrite the  SharePoint webparts, but is it possible for the IFrame application to get windows authentication passed to them?  The legacy applications use windows authentication to authorise and filter data.

What technology/technique would one use?   Will users get a windows prompt for the applications?

Thanks

Jason