Windows Media Rights Manager is a digital rights management
(DRM) platform that can be used by content providers and retailers
to distribute digital media files securely over a network, such as
the Internet. The Microsoft Windows Media Rights Manager Software
Development Kit (SDK) helps protect digital media content (such as
songs and videos) by packaging Windows Media files in an encrypted
file format. A packaged file contains a version of a "protected"
file that was encrypted and locked with a "key" after business
usage and distribution rules were added to the content header. This
packaged file is also bundled with additional information from the
content provider and, optionally, from the distributor. The result
is a protected Windows Media file that can only be played by a user
who has obtained a license.
The basic Windows Media Rights Manager process is as
follows:
Protecting. The content owner or content provider adds
business usage and distribution rules to the content. (For example,
this process could include setting the playback count rights, the
license validity duration, or the ability of the distributor to
update specific usage rules.) Once the file is protected, it can
only be used or opened by specified users. For commercially
distributed files, the content owner can include "Anyone" as a
user, but can specify that certain distributors can change one or
more of the usage rules to meet their business requirements.
Typically, the content provider then sends the protected file to
the distributor for packaging.
Packaging. The distributor packages the digital media
file using Windows Media Rights Manager. The packaged file has been
encrypted and locked with a "key." This key is stored in an
encrypted license, which is distributed separately. Other
information is added to the file, such as the URL where the license
can be acquired. This protected file is saved in Windows Media
Audio format (.wma file name extension) or Windows Media Video
format (.wmv file name extension).
Distribution. The protected file can be placed on a Web
site for download, placed on a server for streaming, distributed on
a CD, or e-mailed to users. Windows Media Rights Manager permits
users to send copy-protected files to friends, as well. The
distribution rules are set by the content owner and the distributor
according to their desired business rules.
Establishing a license server. The content provider
chooses a clearinghouse that stores the specific rights or rules of
the license and implements the Windows Media Rights Manager license
services. The role of the clearinghouse is to authenticate the
customer's request for a license. Files and licenses are
distributed and stored separately, making it easier to manage the
entire system.
License acquisition. To play a protected file, the user
must first acquire a license key to unlock the file. The process of
acquiring a license begins automatically when the user attempts to
acquire the protected content, acquires a predelivered license, or
plays the file for the first time. Windows Media Rights Manager
either sends the user to a registration page where information is
requested or payment is required, or "silently" retrieves a license
from a clearinghouse.
Playing the file. To play the file, the user needs a
player that supports Windows Media Rights Manager. Support for
Windows Media Rights Manager was first added to Windows Media
Player for Windows XP. Players that were created using the Windows
Media Player ActiveX control version 8 or later also support this
DRM platform. With the appropriate version of the Player installed,
the customer can then play the file according to the rules or
rights that are included in the license. Licenses can have
different rights, such as start times and dates, duration, and
counted operations. For instance, default rights may allow the user
to play the file on a specific computer and copy the file to a
portable device. Licenses, however, are not transferable. If a
customer sends a protected file to a friend, this friend must
acquire a different license to play the file. This per-computer
licensing scheme ensures that the protected file can only be played
by the computer that has been granted the license key for that
file.
For more information, see the Digital Rights Management page at
the Microsoft Web site.
