By Matt Rosoff [bio]
Posted: Apr. 18, 2005

• Sidebar: Microsoft's DRM Technologies
• Illustration: One Piece of the DRM Puzzle
• Sidebar: Rights Management Service Pack Planned

The following is the full text of an article published by Directions on Microsoft, an independent research firm focused exclusively on Microsoft strategy & technology. Each month we make one or more key articles available to non-subscribers.

The Business Case for DRM Interoperability

Microsoft and its partners have two distinct reasons to want an effective DRM platform on Windows.

Entertainment. Microsoft's home entertainment strategy envisions the Windows PC as the center of home entertainment, with partners distributing content and selling devices such as players and specialized entertainment PCs. However, this strategy requires content, and publishers won't provide it if Windows does not have DRM to prevent unauthorized copying and sharing.

Enterprise. Microsoft sees enterprise document management—coordinating the creation, distribution, and archiving of documents and e-mail—as key to the continued growth of its Office suite and related products such as SharePoint Portal Server, which also generate systems integration and other add-on business for partners. But some enterprises or business units (such as legal departments) want document management systems with DRM to finely control who can view, print, copy, or forward documents and messages. Adobe and other vendors that provide enterprise DRM have emerged as competitors to Microsoft's document management line.

Microsoft has two distinct DRM technologies for these two tasks. For entertainment, Windows Media DRM allows content owners, such as record companies and movie studios, and distributors, such as online music stores, to define what end users can do with digital media content. For the enterprise, Windows Rights Management Services (RMS) allows end users within large organizations to define how material that they create, such as documents and e-mails, can be used. (See the sidebar "Microsoft's DRM Technologies".)

Why Interoperability Matters

Lack of interoperability threatens demand for DRM in both entertainment and enterprise spaces.

Entertainment. Windows Media DRM faces competition from Apple's FairPlay (used in its iPod and iTunes Music Store), RealNetworks' Helix, and Sony's MagicGate, among others. Today, these DRM systems are incompatible: a piece of content protected by one scheme can only be played by client software and devices that support that scheme.

This fragmentation creates extra hassle for consumers, making them more likely to stick with unprotected content, including illegally copied material that is readily available on file-trading networks such as Kazaa and Grokster (bad for content owners), or to avoid the PC as a digital media tool altogether (bad for Microsoft). It also creates extra work and expense for content owners and distributors, who must use multiple DRM technologies to reach the widest number of consumers.

Enterprise. In the case of enterprise DRM, customers want to be able to exchange protected material with customers and partners. This market is still quite young, and interoperability has not yet become a major issue here as it has with digital media. Nonetheless, lack of interoperability could eventually stall growth, as customers grow reluctant to install a DRM system that is incompatible with those used by its contacts.

Standard Rights Language a Starting Point

Microsoft believes that establishing a universal rights expression language (REL) is the first step toward enabling DRM interoperability.

An REL is used to express policies defining what end users are allowed to do with a particular file, such as, "This item may be opened for 30 days from when it was created, but not after that," or "This item may only be copied to three PCs and five portable devices." This ability to define uses in turn enables applications to perform authorization: enforcing rights by allowing or preventing particular operations, such as copying, forwarding, or printing.

If all DRM systems understood the same REL, then they could all perform authorization consistently and grant users the correct rights to content. But just understanding the same REL is not sufficient for interoperability: DRM systems would also require common methods for carrying out other tasks, such as authentication—that is, identifying applications, devices, and users accessing content. A common REL would be an important starting point though. (For more details on the challenges of DRM interoperability, see the illustration "One Piece of the DRM Puzzle".)

Microsoft appears to be throwing its support behind XrML, an XML-based language developed by ContentGuard, as the basis for this universal REL. In 2001, Microsoft licensed XrML for use in RMS, which was released in 2003. Then, in Mar. 2005, Microsoft joined with Time Warner (a major owner and distributor of digital content) and Thomson (a major consumer electronics device manufacturer) to acquire ContentGuard. XrML has also been used by the Moving Pictures Experts Group (MPEG), an influential body that sets standards for digital media, as the basis for MPEG-REL.

No Convergence Planned for Windows Media, RMS

Given this lineup of supporters, future versions of Windows Media DRM will almost certainly use XrML. This would lead to both of Microsoft's DRM products using XrML.

However, that does not mean that the two products will converge on a single technology—rather, Microsoft says their development will continue on separate paths for the foreseeable future. Rationalizing the product lines could have benefits—for example, it might make it easier to build searchable archives containing both DRM-protected text and digital media—but this is a lower priority for the product teams than improving each product individually.

Interoperability Barriers

Despite the endorsement of XrML by Microsoft and several other important parties, DRM interoperability still faces major challenges.

Competing RELs. Although XrML itself is not patented, some specific uses of it are. As a result, some organizations have rallied around different RELs or created their own. In digital media, the main competitor to XrML is the Open Digital Rights Language (ODRL), which is favored by the Open Mobile Alliance (OMA), a coalition consisting of mobile device manufacturers and wireless carriers. In the enterprise space, most RMS competitors (such as Adobe) use their own RELs.

Different approaches. Some companies agree with Microsoft that DRM interoperability is important, particularly for digital media, but differ on what's necessary to achieve it.

For instance, the Coral Consortium, whose members include consumer electronics companies (Matsushita, Philips, Samsung, Sony), content owners (NBC, Twentieth Century Fox, Universal Music), and Hewlett-Packard, is building DRM specifications based on a framework developed by ContentGuard rival Intertrust. (Philips and Sony acquired Intertrust in 2002.) This framework, the Networked Environment for Media Orchestration (NEMO), addresses problems such as how participants in a DRM system can discover one another and how they can establish trust relationships, but does not envision a single universal REL. In particular, Coral believes that XrML is too complicated for simple digital media transactions in which a consumer electronics device needs to know simply whether a user may or may not play a particular file.

Another group, the Content Management Licensing Administrator (CMLA, formerly "Project Hudson"), which includes Intel, Nokia, Panasonic (Matsushita), RealNetworks, and Warner Brothers Studios, is working on defining a trust model for telephone handsets that use the OMA DRM system.

Incumbency. One of the most important players in digital media DRM—Apple—has little interest in fostering interoperability. Apple currently dominates the markets for portable music players and online music downloads, and its proprietary FairPlay DRM system has helped to create user lock-in. A similar situation could arise in enterprise DRM if Microsoft or another company achieves a dominant position.

Other DRM Problems More Pressing

Both of Microsoft's DRM products face a number of other pressing problems, which Microsoft is currently giving higher priority.

Windows Media. Microsoft's main priority for Windows Media DRM is adding new features that will help make the overall Windows Media platform more competitive. For example, the latest version of Windows Media DRM (released in fall 2004) supports the transfer of subscription-based ("all you can eat") and rental-based content to devices, while Apple's DRM system only supports a "pay as you go" model in which users pay for each download. According to Windows Media Product Manager David Caulton, interoperability is definitely on the radar, but it is a lower priority than adding new competitive features.

RMS. The RMS team is also focused on problems other than cross-vendor interoperability. In Apr. 2005, Microsoft announced plans to release a service pack that will fix some early problems with RMS, such as its lack of support for smart cards. (For more details, see the sidebar "Rights Management Service Pack Planned".) For the next version, which is due around the time of the next Windows client OS (which is code-named Longhorn), the RMS team plans to improve RMS's support for business-to-business exchanges of protected material. Cross-vendor interoperability could become more of a focus around the time of this release, but significant cooperation will be required—including other vendors' supporting XrML.

Action for Customers, Partners

Given these challenges, customers and end users of DRM systems should not expect a useful degree of cross-vendor interoperability in the near future, and partners who are hoping to build a business around DRM should understand that lack of interoperability could hurt demand for these products.

Windows Media DRM. Microsoft recommends that partners and customers interested in addressing DRM interoperability work through the Digital Living Network Alliance (DLNA, formerly known as the Digital Home Working Group), which was founded in July 2003 and includes many major PC industry, consumer electronics, and mobile industry players. So far, however, this group has focused on other problems, such as agreeing on protocols for adding devices to a home network, and it has not revealed any concrete plans to enable DRM interoperability.

In the meantime, influential companies might be able to strike ad hoc DRM interoperability agreements with Microsoft. For example, in Feb. 2005, Microsoft signed an agreement with Nokia to allow the Windows Media Player to support OMA DRM with the aid of a plug-in; in exchange, Nokia agreed to create a plug-in to support Windows Media DRM in some future handsets.

RMS. Organizations that need to exchange protected material with partners and customers should compare RMS's business-to-business capabilities with those provided by other vendors, keeping in mind that these solutions are not interoperable with one another.

Resources

Background on RMS, including architectural overviews of how content is protected and accessed, can be found in "Rights Management Secures Office Content" on page 4 of the Dec. 2003 Update. The RMS home page is at www.microsoft.com/windowsserver2003/technologies/rightsmgmt/default.mspx.

An architectural overview of Windows Media DRM is at www.microsoft.com/windows/windowsmedia/howto/articles/drmarchitecture.aspx. Information on the role of Windows Media and DRM in Microsoft's overall consumer strategy can be found in the Feb. 2005 Research Report, "Microsoft's Home Entertainment Strategy."

The Microsoft-Nokia DRM deal is described in "Nokia, Microsoft Sign Digital Music Deal" on page 26 of the Mar. 2005 Update.

More information about XrML is available at www.xrml.org.

Two sites that keep track of the many coalitions working on some aspect of DRM interoperability are DRM Watch at www.drmwatch.com and an OASIS-hosted page at xml.coverpages.org/drm.html.

The Coral Consortium is at www.coral-interop.org.

The CMLA is at www.cm-la.com.