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White Paper K300i
26 February 2005
DRM
Digital Rights Management, DRM, is a technology
that enables secure distribution, promotion, and
sale of digital media. Examples of such content
include images, wallpapers and screen savers with
themes from films, music tones from musical
artists, and branded games. In other words,
content providers can control how users may use
different types of content in devices, such as
mobile phones, smartphones or PDAs. Content
providers can also control the use of content in
related services, such as MMS.
Sony Ericsson is actively focusing on technology
standardization for the DRM concept, and supports
the ongoing standardization work and activities of
the OMA (Open Mobile Alliance). Sony Ericsson is
fully committed to open standard solutions in the
mobile environment and is a principal driver of
many open standard initiatives. This will ensure the
interoperability of mobile terminals in the DRM area
and also result in a strong, competitive DRM
standard.
How DRM works
The control of the content in digital media is
executed by defining usage rights for the content.
The usage rights give the content providers
flexibility in the way they can publish and sell
content. Rights can be defined so that a picture
can be used by subscribers only, and rights can be
defined so that a ringtone can be played only a
limited number of times or for a limited period of
time. Rights can also be defined so that the user is
not able to forward content to other devices.
Packaging of rights and content
Rights and content can be packaged together and
delivered to the device as one DRM package. As
an alternative, content can be delivered to the
device first, followed by the rights later being
pushed to the device, for example via SMS. The
kind of service and business model adopted by the
content provider determines how the content and
rights should be packaged and delivered to the
device.
Protection properties
Content protection according to the OMA DRM
standard gets special properties. Content with
forward lock protection has the “Send to” option
disabled, which prevents it from further
distribution.
Unless the content is encrypted, the user cannot
copy DRM content to other devices since the Send
to option is disabled for pictures, music tones, etc.
that are OMA DRM protected. Content providers
may choose to protect some content, but leave
some content unprotected.
Package and delivery
The OMA DRM standard defines two ways to
package and deliver rights and content to a device:
combined or separated.
Combined delivery
Rights and content are packaged together into one
DRM Package and delivered to the device. In the
simplest case, no special rights are defined. The
content is just put into a DRM package, thus
protected from being copied out from the device by
the user. This special case is called forward-lock.
It is useful for all types of content that the provider
wants to charge for.
Separate delivery
Rights are defined and sent in a push message.
The content is encrypted and made available for
users to download to their devices. The decryption
key is put into the rights file. Since the content is
encrypted, users cannot access it before the rights
have also arrived in the device. In this case, the
content can be freely distributed on the network,
only users with the rights file can access the
content. Content providers can deliver the rights to
the user using push technology.
Downloading servers and
publishing servers
When using a mobile phone, the users do not have
to be aware of the network architecture. During a
content downloading session, typically many