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Why DLNA?

Broadband is the new speed of choice. Meanwhile, new digital entertainment and mobile devices are introduced every day. Enabling these products to seamlessly interact is good for consumers. And for the industry.

Digital Rights Management / Content Protection

In order for commercial digital content to be made available for use with DLNA devices, content must be protected from unauthorized copying and use. Consumers acquire commercial content from different channels (cable, satellite, Internet, etc.) at different price points; the usage rights associated with content acquired through different channels are also typically different. For example, a movie ordered through pay-per-view on a cable set-top box has different usage rights from a video purchase from an Internet video download service. At the same time, consumers expect to be able to store, transport and use that content at any location and on any device on their wired or wireless home networks. Balancing the providers’ need for protection from unauthorized use and copying, while providing interoperability between all networked devices that might handle the content, is a complex problem. Content protection methods must also be user friendly.

Today, there are several Digital Rights Management (DRM) technologies available to device designers and content providers. One or more of these solutions will typically be provided on DLNA devices to protect, administer and distribute stored content as one component of content protection in the digital home. However, commercial content cannot be shared across devices with different DRM technologies unless there is an interoperability mechanism for content to flow from the source device to the destination device. The interoperability mechanism must provide a technical DRM interoperability solution (ability to transform content protected using the source DRM to content protected using the destination DRM in a secure fashion) while respecting the usage rights and policy associated with the content. DLNA has identified DRM interoperability as the core charter of the content protection guidelines work within DLNA, recognizing that it is a key layer of interoperability that allows commercial content to be shared across all devices that belong to a consumer.

Given the complexity of DRM interoperability, the initial efforts of the content protection subcommittee in DLNA focused on link protection technologies to protect content in transit from a source (DMS, DMC or DMP) to a display device (DMR). The Content Protection Subcommittee completed its link protection guideline work in March 2006, resulting in the publication of the DLNA Networked Device Interoperability Guidelines Expanded, October 2006, which include link protection. The Content Protection Subcommittee is now focused on developing DLNA DRM interoperability guidelines.

When a DLNA device supports DLNA Link Protection, then the DLNA Interoperability Guidelines Expanded, October 2006 mandates that the device must support DTCP-IP and may support WMDRM-ND. If an UPnP AV Media Server supports DLNA Link Protection, it must be capable of exposing and transferring at least one of the DLNA media format profiles with DTCP-IP link protection.

Other components of DRM that support additional user scenarios are being considered for development in standard organization and elsewhere in the industry.

How DRM Differs from Link Protection

The primary use case for link protection is that commercial content, which is stored on the DMS and protected by a DRM technology, is decrypted and re-encrypted using a link protection technology by the DMC (for example, mobile device) or DMP (for example, digital media player/ DVR) before being sent to the DMR (such as a television). The DMR decrypts the content stream and then displays/outputs it.

DLNA thus provides a useful venue for those who share the vision of device interoperability. Collaboratively, manufacturers can understand and document the range of technical and business requirements for achieving the required balance between protection, availability and usability. This work will aid device designers and content providers in implementing DRM methods today and in the future, to foster an integrated, user-friendly, and backward compatible system that meets the rights, needs and expectations of all stakeholders.