We occasionally get questions from customers about creating custom IRM protectors. Protectors are components that are used to apply AD RMS protection to files when they are added to document libraries like those in Windows SharePoint Services 3.0. Specifically, protectors “convert custom files types to rights-management formats when the user downloads them, and then convert those files back to nonencrypted file formats when the user uploads them for storage in the document library.”
The AD RMS team recently released an IRM protector implementation that protects files in Microsoft Office formats, such as .docx, .xlsx, and so on. Included with these is some documentation that can help you implement these protectors provided by the AD RMS team or with your own custom protector implementation.
Documentation_OfficeFileFormatProtectors – This document contains reference documentation for the protector interface and other required interfaces.
Developer’s Walkthrough Microsoft Office 2007 File Format Protectors for AD RMS – This document discusses setting up a pre-production development environment and implementing the I_IrmCyrpt interface, which is used to enable document encryption and decryption, and I_IrmPolicyInfoRMS, which holds licenses and other information used by a protector.