Digital Right Management


The problem of unauthorized copying and transmitting of digital media across the Internet is a major concern for content owners and software industry. Until today, many conventional technologies used to prevent and eliminate unauthorized distribution of digital materials have proved to be inadequate and costly; they have many shortcomings and pitfalls. Digital Right Management (DRM) system, however, can replace these technologies with more flexibility and lower cost. This proposal report shall examine in more detail the problem of unauthorized distribution of digital media, and the shortcomings of conventional prevention methods. It will then introduce DRM technologies, look at their implementation issues, and provide some insights on the future development of DRM.

The Problem

The web is an ever growing entity of internetworked communities where sharing of digital materials is very easy at the click of a mouse. These digital materials are basically audio, video, e-books, software and documents. Some of the frequently used file types are MP3s, MPEGs, JPEGs, and PDFs. Millions of copies of these file types are digitally flowing across the Internet. They are passed between users via web sites and FTP sites, or exchanged on corporate or college intranets.

The real problem is to design a method to stop, or at least slow down this undisturbed exchanging rate of copyrighted digital materials. There are many inherent obstacles, such as the exponential expanding rate of the Internet, the speed of transmission, the increasingly sophisticated technology of the transmission protocol and the numbers of protected copyrighted materials.

Conventional Prevention Technologies

There are several conventional prevention technologies worth mentioning because they can pin point the exact problem. One of the technologies is called “web crawling”, where suspected sites and file-sharing communities are visited and monitored individually for illegal use of copyrighted material. When a connection is found misused, the users and the Internet Service Provider (ISP) will be contacted. However, constant searching and monitoring is very costly, and it becomes more difficult as the Web expands and contents are hidden under different forms. Another technology is called “network hardware intervention”. This approach utilizes networking hardware to control where and how contents will be routed. Unfortunately, once a site is suspected, all contents will not be routed to the original recipients but to elsewhere. This is extreme and inflexible for many corporate and university intranets or online communities.

Digital Rights Management (DRM) Technologies

The shortcomings of conventional prevention technologies stem from the fact that they are individual technologies that can only fix certain parts of the problem but not the whole problem. DRM system, however, is a collection of coordinated technologies that can detect, track and possibly stop this illegal transmission of digital materials.

In order to detect, track and interrupt the transmission of digital media across the web, the media must first be modified. DRM system provides several forms of encoding methods, and these depend on the value of the media. One form is called “tagging”, where the verification information is added to the file name or header of the media. This method is simple and very efficient. However, it is generally used for materials with little importance since the tag is unconditionally easy to modify. A more robust and secured form is called “digital watermarking”, where a digital watermark is embedded into the media. A digital watermark is an identification code, permanently embedded into digital data, carrying information that is necessary to copyright protection and data authentication. This code is “invisible” (i.e. can only be detected by producer of the watermark). These methods provide many advantages: one is the ability to remain intact even if the media is reproduced or modified; secondly, it can be designed in such a way that detection can be done on-the-fly, which makes it very attractive under high transmission speed. The diagram below shows an example of a digital watermarked JPEG image.

Original Image
Original Image
Watermarked Image
Watermarked Image

In addition to watermarking digital data, monitoring software programs are placed at strategic points on participating networks. For example, in university intranets, the software can be placed at points where users can reach the Web or between LANs. It acts like sniffing software that is actively monitoring the content as it passes by each point. The software then tries to determine the content type (MP3s, MPEGs, JPEGs or PDFs). Once the type is known, using filtering technologies, the software will filter the digital watermark on the fly and compare it to existing databases for copyright verification. In addition, it also checks the IP address information to determine the identity of the sender and receivers. With this information, it can determine whether or not the transmitted data has been authorized. Once the transmission is found illegal, the software will, depending on the value of the content, can:
  • send a message to the users informing of their action,
  • requesting the service providers to stop the transmission,
  • track the contents to determine traffic statistics and other important information
Implementation Issues

To make DRM system fully functional, the following issues must be resolved. First of all, detection, tracking and intervention processes must be in real-time. With the ever-increasing transmission speed, this requirement will become stricter. As digital watermarking technology improves upon itself, there are many promising techniques existed on the market today. It is very important to determine whether a DRM system be implemented based on speed or security, because these two are tradeoffs and dependent on the type of the content involved.

Secondly, the software must be placed at appropriate transferring points on the Internet. This process requires much research on the behaviour of the users. Again there are tradeoffs here between the number of implementations, the performance of the system and the right placements.

The third issue involves network services providers. They are mainly of two types: Internet Services Providers (ISP) and private network services providers. These providers must co-operate on two grounds: one is to allow DRM software to be installed at certain points on their networks, and the other is to intervene the transmission when DRM software requests. For example, DRM software can request the ISP to interrupt user A from transferring unauthorized content to user B under the condition that either one or both users receiving services from this ISP.

These implementation issues are as crucial as the software itself. They affect the performance, security, effectiveness and cost of DRM system.

Future Development

The Recording Industry Association of America (RIAA) has been using this technology to prevent illegal transmission of MP3s. For example, RIAA has rejected thousands of users from downloading MP3s through Napster (an MP3 sharing server). Many other recording companies have also joined in. Although the main purpose behind this technology is to terminate the MP3 phenomenon, other digital materials have also been protected using similar technologies. Recently, Random House, a major e-books publisher, has adopted DRM to label and track all of its digitized materials. Although currently DRM has not been standardized, and DRM vendors often offer different views on how a system works best, many predict an emergence of DRM standards within a few years. Since DRM system relies heavily on digital watermarking technologies, many complicated watermarking algorithms have been developed. More and more researches are being conducted on DRM.


As the size of the Internet continuously expands at an extraordinary rate, DRM technologies provide a more attractive solution to detect, track and stop the flow of unauthorized digital material, than conventional prevention technologies. With its flexibility and real-time performance, DRM continues to improve on these two grounds. Also, with the convergence of DRM standards, DRM will apparently be a better choice for managing digital materials. With DRM, everyone can protect his/her own intellectual materials from unauthorized copying and distribution.

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