pCDN and DRM overview
To distribute multimedia objects over the Internet, there are some options for the content providers to do that. One option is to build a server farm with huge network connections, but this option is not scalable and not cost effective because the number of consumers is rapidly increasing. The second option is to use Akamai or any other content delivery network (CDN). The CDNs give better performance but they are costly. The third option for the content providers to distribute multimedia objects to millions of users over the Internet is using pCDN, peer-assisted content distribution network. pCDN benefits from the tremendous success of the peer-to-peer (P2P) computing paradigm. pCDN is a good approach to relieve the costs incurred in content distribution. pCDN provides improved scalability, reduced cost, and rapid deployability. Therefore, pCDN may achieve similar services as CDNs at a fraction of the cost. The core idea of pCDN (which is still investigated) is to deploy seed servers that will manage client request by redirecting the client to other clients (peers) who recently received the same requested multimedia object. The client will contact these peers to receive the requested object from them. This idea has worked with file-sharing P2P systems but with some challenges such as, optimizing video quality, reducing the traffic load on Internet Service Provider (ISP) networks, efficient video transmission from multiple senders, restricting content to certain locations, and digital rights management, i.e., provide service to legitimate clients [BM07]. One of the most important issues that the pCDN as well as any content industries want to take care of is digital rights management. Digital rights management- DRM for short- will help artists, producers as well as consumers to benefit from the apparently unlimited potential of the Internet. DRM apply some constraints, like how to use and distribute, on digital goods. These constraints can be imposed by associating rules to the content that are mostly used. Some people see the DRM as Digital Restriction Management, because they see the basics rights of consumers are restricted where before the consumers were able to exercise fair use exceptions. Therefore, we can see the DRM systems as a friend or an enemy, depending on how the people deal with it. DRM has some functions and these functions will include everything that anyone does with content to trade it. DRM functions are about managing digital rights and digitally managing of rights. Managing digital rights is about what the rights holders need. They need to identify their content, they need to correlate metadata to the content, they need to assert what rights they have in the content, and they need to develop business models for distributing their assets.[] The second DRM functions is about Digitally managing of rights. It can be seen as enforcing rules as defined by the rights holder or their partners (i.e., distributors, wholesalers, etc.).
How to manage DRM system?
To manage DRM, it is important to understand three very important issues : technical, legal, and business matters [DRMT]. The technical issue focuses on how to understand the scope and limitation of DRM technology. The legal issue provides a legal basis for the relationships between content consumers and content providers. The business issue focuses on many topics and what these topics mean, such as copying, electronic markets, impacts on innovation, business models, and user acceptance of DRM systems. None of these issues can work by itself. In fact, the DRM technologies that we use are dependent on the legal system and both of these issues depend on the business models in operations.
DRM environment
The above issues are subject to several external factors, such as, economic aspects, social, and international aspects. These external factors are very important for the DRM success. Economic aspects give a good view of the market situation. This view helps the rights holders and their partners to determine which technology and business models they can use. The economic aspects also help to determine if the consumers are willing to use content with these new formats. Social aspects focus on how socially acceptable it is to use DRM systems. These two aspects cannot work without taking into account the third critical issue which influences the use of the DRM systems, international aspects. We know the rights situation differ from country to country, and we are sure when any content made available on the Internet, it is automatically available to everyone. For these reasons, we have to investigate the international aspects. When all these aspects are taken care of, the DRM system with all its elements become successful.
DRM Elements
From the definition of the DRM systems, we know DRM systems have to cover a variety of tasks. There are some elements exist to fulfil these tasks [DRMT].
1. Secure containers: for the users who do not have rights to access the content, the content will be inaccessible. The content, access conditions as well as the license server URL (the server that has the exchange keys) can be seen as putting them in a locked container. This locked container will transmit to the client and unpacked based on the information rules inside it.
2. Rights expressions: express who is permitted to access the content wrapped in secure containers.
3. Content identification and description systems: identify the content and join metadata description with the content.
4. Identification of people: identifies the consumers who intend to interact with the content.
5. Authentication of people: authenticates the people who want to interact with the content.
6. Watermarking and Fingerprinting: join identifiers and other information with the content. Hence both of them are used to prove that a violation has happened.
7. Report events: a mechanism is used to report any events such as a purchase of content. It allows the event that is based on payments to work.
8. Payment systems: these systems which are enabled through event reporting systems need to be coordinated into the system. The above elements need to be attached together. When these elements are attached, participants in the DRM content (from the owner through several service providers to the end user) trust system to do what they expect it to do.
References and Links
- DRM at Microsoft : http://www.microsoft.com/windows/windowsmedia/forpros/drm/default.mspx
- [DRMT]Digital Rights Management Technological, Economic, Legal and Political Aspects Series: Lecture Notes in Computer Science , Vol. 2770 Becker, E.; Buhse, W.; Günnewig, D.; Rump, N. (Eds.)
- [BM07]B. Jules and M. Hefeeda, pCDN: Peer-assisted Content Distribution Network, CBC/Radio-Canada Technology Review Magazine, Issue 4, pp. 1--14, July 2007
