MPEG-4 Intellectual Property Management and Protection Extension (IPMP-X)
MPEG doc#: N7505
Date: July 2005
Author: JI Ming (Panasonic)
MPEG-4 Part 13 is a specification on IPMP-X (Intellectual Property Management and Protection Extension), which is a DRM (Digital Right Management) architecture developed by MPEG. IPMP-X provides a normative framework to support many of the requirements of DRM solution: renewability, secure communications, verification of trust, granular and flexible governance at well-defined points in the processing chain, etc.
Why did MPEG work on MPEG-4 IPMP-X?
Digital Rights Management (DRM) is a technology that has been developed to protect against the illegal distribution of copyrighted digital content such as music, video or documents. However, there are some problems remained to be solved in the existing DRM market. The first problem is the lack of interoperability. Different content providers tend to use different protection mechanisms (different DRM systems) to protect and distribute the content, hence terminals often encounters the case whereby a content protected by unrecognized DRM system is not able to be played. The second problem of the existing DRM market is the lack of renewability. Many existing DRM systems are likely to be broken, due to the rapidly growing computer technology. It is therefore desirable to establish a robust and flexible DRM framework, where one can easily renew a broken DRM system.
The lack of interoperability problem demands an international standardization effort, so that contents can be delivered anytime, and to anywhere in the world. Being able to expect different vendors’ content to play on a single player is a big deal. Not having to re-engineer a given player to work with every other DRM system is an even bigger deal.
How does MPEG-4 IPMP-X work?
To achieve the robustness, MPEG-4 IPMP Extension provides the tool renewability, which protects against security breakdown. The flexibility allows the use of various cipher tools, as well as decoding tools. The interoperable framework enables the distribution and consumption of content all over the world. MPEG-4 IPMP Extension defines 5 key elements as described below.
1) IPMP Tools: IPMP tools are modules that perform (one or more) IPMP functions such as authentication, decryption, watermarking, etc. A given IPMP Tool may coordinate other IPMP Tools. Each IPMP Tool has a unique IPMP Tool ID that identifies a Tool in an unambiguous way, at the presentation level or at a universal level.
2) IPMP Descriptors: This is a part of the MPEG-4 object descriptors (OD) that describe how an object can be accessed and decoded. These IPMP Descriptors are used to denote the IPMP Tool that is used to protect the object. An independent registration authority (RA) is used so any party can register its own IPMP Tool and identify this without collisions.
3) IPMP Elementary Stream (ES): IPMP specific data such as key data, rights data are carried by the IPMP ES. All MPEG objects are represented by elementary streams, which can reference each other. These special elementary streams can be used to convey IPMP specific data.
4) IPMP Tool List: IPMP Tool list carries the information of the tools required by the terminal to consume the content. It is carried in the Initial Object Descriptor (IOD) of the MPEG-4 system stream. This mechanism enables the terminal to select, manage the tools, or retrieve them when the tools are missing.
5) Secure Messaging Framework: The MPEG-4 IPMP Extension framework did not choose the approach of defining functional interfaces, instead, it is based on secure message communication. This is one of the most important concepts in MPEG-4 IPMP Extension. Interaction between the terminal and the IPMP Tools are realized through the messages via a conceptual entity called “Message Router”. Syntax and semantics of the messages are clearly defined to facilitate full interoperability. Mutual authentication and secure messages are also introduced to achieve a secure framework.
The Architecture of MPEG-4 IPMPX
 ISO/IEC 14496-13, Intellectual Property Management Protection (IPMP) extensions
 ISO/IEC 14496-1, Information technology — Coding of audio-visual objects — Part 1: Systems