Protecting Documents Outside The Repository: Documents can be protected outside of the DM repository (e.g. when someone downloads a file to their laptop) when the administrator sets an Information Rights Management (IRM) policy on the library. When the document leaves the library the content is encrypted and a set of rights (e.g. controlling only viewing, printing, or expiring a document for viewing after a certain time period, etc.) and will only be unencrypted once the user is validated and the specific operation requested is approved.
The following article, “7 New Features That Enhance Security in SharePoint”, discusses this functionality in greater detail.