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Marlin – The Open DRM Scheme Sony Uses For Content Distribution

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In today’s world, the fact that digitized music, images or video can be copied without any loss of quality, derived from the popularization of the internet and improvements of its speed with greater performance and the capacity of PCs, has increasingly resulted in the illegal copy and reuse by third parties without the permission from copyright holders. In a recent interview, Sir Howard Stringer, CEO/President of Sony stated “A lot of people thought Sony’s content download service was doomed, but it’s in a pretty good place right now in the form of the PlayStation Network, available to PS3 users for network gaming, video, etc. The DRM is based on Marlin, an open scheme developed by consumer electronics companies and other companies. What does all this mean? Very simply, it means that Sony has begun the transition from a closed system to an open one.”

Digital rights management (DRM) technology has widely been used to protect copyrighted digital content by controlling or restricting copying. In 2005, Sony, Intertrust Technologies, Matsushita Electric Industrial, Philips and Samsung Electronics established the Marlin Joint Development Association (Marlin JDA) to develop technical specifications of DRM for use in consumer electronic products. Manufacturers can implement Marlin DRM, which supports content distribution over the internet, broadcast or mobile segments, in their products. Marlin compliant content and devices will enable users to enjoy content no matter what device they use and no matter how they acquire content.

There are some Marlin DRM specifications for various purposes. The two most promising types are Marlin BB (Broadband) and Marlin IPTV-ES.

Marlin BB-provides multiple copies among user’s devices

As the name suggests, Marlin BB is designed for use in distribution via broadband internet. A communication protocol based on the web service technology called NEMO is used for the content distribution. Messages are exchanged using XML format (*) and RSA (a public key cryptography) is used to exchange decryption keys. The usage rules of content are written in byte-code called Plankton and the content itself is encrypted by the Advanced Encryption Standard, an encryption system endorsed by the U.S. government.

One of the most characteristic parts of Marlin BB is its support for the domain model. Other proposed DRM systems have failed to offer a simple way to share downloaded AV content among devices. The domain model concept was introduced as a way of overcoming this drawback while still protecting copyrights. A domain is a group of devices among which the user wishes to share files. A domain model can be created using the following method.

  1. The user and the user’s devices are registered on the Marlin service server.
  2. The server creates a domain key for that user.
  3. The server issues a domain key to each device and the device securely stores
    the domain key.

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Registering Devices on a Domain

In order to download content, the distribution server sends the encrypted content and the license to the device. The content is decrypted with the content key using the AES algorithm. The license includes the content key (which has been encrypted using the domain key) and the content usage rules. To play back content, the domain key is used to decrypt the encrypted content key contained in the license. The device then uses the content key to decrypt the encrypted content, which can then be played back in accordance with the usage rules stipulated in the license. Because the user is entitled to copy the content among devices that belongs to a domain under the same domain key, it is possible to offer the same kind of experience users get with MP3 files.

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Downloading Content

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Content Playback

IPTV-ES-for Digital Television Platforms

IPTV-ES was introduced in 2007 as the first DRM system designed for the IPTV business in Japan. In addition to streaming applications such as video on demand (VOD) and IP multicast, this technology also supports download service, whereby content is played back after being stored on a hard drive or other devices, and exporting functions, which allow content to be written into media protected by different DRM systems such as Memory Stick or Blu-ray discs. It is suitable for the latest digital television platforms, which support DLNA (DTCP-IP) (*). The content is securely protected using the AES algorithm.

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Support for IPTV-ES

Sony has extensive experience with DRM technologies including OpenMG. Marlin BB and Marlin IPTV-ES were created based on familiarity with these technologies. Sony introduced Marlin enabled products in 2007 starting with BRAVIA models in Japan and PlayStation Network service with PS3 and PSP. More Marlin enabled products are planned for the future. If the usage rules are too restrictive or complicated, DRM technology can become a nuisance for users. If the usage rules are too lax, illegal copies may thrive wich, in turn, prevents it will content providers from investing in future productions. Electronics divisions within Sony have led the industry as a bridge with content holders and service providers and remains committed to support user-friendly DRM technology that consumers feel secure about using.

While DRM technologies have been developed by IT industry players such as FairPlay made by Apple, or Windows Media DRM (WMDRM) made by Microsoft, there were significant demands from the consumer electronics (CE) industry for a DRM technology that would be more suitable for CE products. Panasonic, Philips, Samsung Electronics and Sony together with Intertrust Technologies, which owns basic DRM technologies, developed a CE friendly DRM called Marlin.

Marlin Organizations

The five founding companies take the initiative to run two organizations. The Marlin Developer Community (MDC) is a forum to develop Marlin specifications together with hosting Community Source Program and promote those activities, while the Marlin Trust Management Organization (MTMO) provides the license of the Marlin specifications together with the certification and compliance program and conducts key management operations for interoperability.

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Marlin Developer Community (MDC)
More than 15 companies are currently members of MDC and cooperate in developing specifications as well as participate in the Community Source Program. Even non-members are able to download all the completed specifications simply by signing an End User License Agreement (EULA). For further information, please visit: http://www.marlin-community.com

Marlin Trust Management Organization (MTMO)
Those wishing to use Marlin technology for commercial purposes must first enter into a licensing agreement with the MTMO. The MTMO has prepared licensing agreements for manufacturers of end-user products, component manufacturers who supply to end-user product manufacturers, service providers and service element vendors who supply to service providers. There are currently more than 25 licensees (as of June 2008). For further information, please visit: http://www.marlin-trust.com/

In addition to these two organizations, a Marlin users forum has been established to support the smooth introduction of Internet Protocol Television (IPTV) in Japan. The purpose of this forum is to study, formulate and provide specific compliance rules and implementation guidelines needed to support commercial use in Japan. It currently has 47 corporate members (as of July 2008). For further information, please visit: http://www.marlinusers-japan.org/index-e.html

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