1.3.2 Information Rights Management Data Space

The Information Rights Management Data Space (IRMDS) structure is used to enforce a rights management policy applied to a document. The structure defines a transform that is used to encrypt document content, and it defines a second transform that can be used for certain document types to compress document content.

The original document content is transformed through encryption and placed in a storage not normally accessed by the application. When needed, the application uses the transforms defined in the document to decrypt the protected content.

This structure is an implementation of the data spaces structure. Therefore, implementing the structure implies storing document content in an OLE compound file.

Applications that implement this structure will typically store a second document in the OLE compound file called the placeholder document. The placeholder document is place into the streams (1) or storages normally identified by the application as containing document content, such that an application that does not detect the IRMDS structure will instead open the placeholder document.

Applications that implement this structure will typically try to follow the licensing limitations placed on a document. Typical licensing limitations include the right to view, print, edit, forward, or view rights data, as described in [MS-RMPR].

The following figure shows the specific storages, streams (1), structures, and relationships among them that are created when the IRMDS structure is used in an ECMA-376 document [ECMA-376].

Figure 2: An ECMA-376 word processing document with the IRMDS structure applied