A P2P Based Secure Digital Music Distribution Channel - Intelligent Music Information Systems: Tools and Methodologies - page 187

enables the identification of the user, marked
“ID” in Figure 4, which increases the security
and trust in the network. It also enables the redis-
tribution of the compensation of the user through
the reward system in place or to track the user in
case of fraud suspicion. This is similar to other
systems already in place such as Wedelmusic
(www.wedelmusic.org) and the Potatoe Systems
(www.potatoesystem.com).
Once the song is in the network, it stays protected
against unauthorized use and access. In addition,
if the content “leaves” the P2P network, it cannot
be opened, because it requires a decryption key.
When a peer requests a song, the peer gets a re-
sponse from the content provider alias super node
or another peer in the network indicating who has
stored this piece of music on the user's hard disk.
The encrypted license, which includes the rights
and the key for decrypting the song, as well as the
encrypted content package, including the content
and the metadata, are sent to the peer. If the con-
sumer is using this service for the first time, the
DRM controller creates a user identity (ID). This
may entail getting the user to fill out a registration
form (e.g., including a number, name, address,
gender, age, credit card details) and clicking to
accept an end-user license or software agreement.
This may be happen already when the user first
downloaded and installed the P2P software. The
user's identity is passed to the license server for
storage in the identity database.
The licensing servers including the rights
management and the key managements server
have the following functions. The license genera-
tor authenticates the peer's identity against it's
identity database and uses the content identifier to
look up the rights information about the content,
manage and issues licenses for legally purchased
music files. In addition, they track the files (e.g.,
who downloaded which files, who is providing
which files to other peers). This information is
important for incentive systems of peers, rights
management, and business models. The license

server increases the security and quality of service
of the centralized P2P network.
Finally, on the peer's side the DRM controller
decrypts both files and forward it to the render
application and the file can be downloaded, played,
stored, copied, modified according to the rights
granted to the user . This exchange can happen
between the super node and peers or directly
between peers.
The DRM in place also includes tampering
detection technologies (e.g., watermarking, digital
fingerprinting) to protect the authenticity and in-
tegrity of the content. Thus, the user is guaranteed
to receive the same high quality content that the
content provider would have released in the case
of the client-server model used.
The following figure shows a simplified cen-
tralized P2P architecture consisting of three main
players: the network consisting of thousands or
millions of users; the super nodes representing
super users or content providers; the individual
peer user.
The peer or client in Figure 4 refers to compo-
nents that reside on the peer or user's side, such as
the DRM controller and the rendering application.
Examples of the rendering application are Win-
dows Media Player from Microsoft or RealPlayer
from RealNetworks, or they might be integrated
in the peer-to-peer software. The DRM controller
is the real “nerve center” of a DRM. It pulls the
content package with the content and metadata,
the license with the associated keys and rights to-
gether. It can be an independent piece of software,
an integral part of a rendering application, or a
hardware device. A DRM controller will carry
out a number of functions as mentioned earlier
such as exercising certain rights over content that
the user requests, clarifying and authenticating
content, and performing all encryption and de-
cryption functions.
The super nodes do not need to store all digital
content, they act more as a “broker” or enabler for
the exchange of digital content. The key reasons