DRM for Portable Devices (Windows CE 5.0)
One of the central goals of DRM is to prevent the duplication of protected media content. There are, however, some legitimate usage scenarios that require users to be able to copy their protected digital content. One such scenario is the transfer of protected content, such as music files, from a desktop computer to a portable Windows CE-based device.
OEMs can enable DRM for portable devices when they create an OS design. This allows the transfer of content from a desktop computer to the local store of a Windows CE-based device or to a supported portable media device connected to a Windows CE-based device. Once content has been transferred to a Windows CE-based device, or to a supported connected portable media device, it cannot be transferred to another device. The one exception is the transfer of content from a desktop computer to compact flash storage. Content is protected based on the unique device identifier of either a Windows CE-based device or a compact flash card. Content that has been transferred to compact flash storage becomes associated with the compact flash card and therefore can be physically moved between Windows CE-based devices. Content can be deleted, but it cannot be moved from device memory to compact flash or from compact flash to main memory.
Content protected with DRM can be encoded to allow a preset number of transfers. Each Windows CE-based device to which protected content is transferred maintains its own separate license derived from the original. Windows Media® Player on the desktop manages the process of deriving the new license, repackaging the original content, and transferring the license and content to a portable Windows CE-based device through ActiveSync. DRM licenses can only be transferred to Windows CE-based devices through ActiveSync.
The following illustration shows how protected content originates from Windows Media Player on the desktop, passes through ActiveSync, and is directed into a memory store on a Windows CE-based device.
.gif "ms923104.cxdrmlicensetransfer(en-us,MSDN.10).gif")
The DRM Helper is an internal OS module within the DRM system on Windows CE that has no public interfaces. It controls DRM-protected content is loaded onto a Windows CE-based device and then manages how that content is placed within the device's available data stores.
See Also
Send Feedback on this topic to the authors