MPEG-21 Intellectual Property Management and Protection (IPMP) Components
MPEG doc#: N7199
Date: April 2005
This part of ISO/IEC 21000 specifies how to include IPMP information and protected parts of Digital Items in a DIDL document. It purposely does not specify protection measures, keys, key management, trust management, encryption algorithms, certification infrastructures or other components that would also be needed as part of a complete IPMP solution.
The IPMP DIDL encapsulates and protects a part of the hierarchy of a Digital Item, and associates appropriate identification and protection information with it. The description of IPMP governance and tools is required to satisfy IPMP for a Digital Item or its parts to be accessed
The aim of ISO/IEC 21000 Intellectual Property Management and Protection (IPMP) Components is to allow controls on the flow and usage of Digital Items throughout their lifecycle.
It exists in two parts:
IPMP Digital Item Declaration Language, which provides for a protected Representation of the DID model, allowing DID hierarchy which is encrypted, digitally signed or otherwise governed to be included in a DID document in a schematically valid manner.
IPMP Information schemas, defining structures for expressing information relating to the protection of content, including tools, mechanisms and licenses
2 IPMP DIDL
The Digital Item Declaration (DID) specification (ISO/IEC 21000-2) defines entities in the DID model, which are used to unambiguously express the structure and content of a Digital Item in the MPEG-21 Multimedia Framework. The Digital Item Declaration Language (DIDL) provides a normative Representation for Digital Items using XML, defined by DIDL elements and attributes which correspond to entities in the DID model.
As a Digital Item expressed in DIDL is a clear XML document, the contents of a Digital Item represented entirely in DIDL are exposed.
IPMP Components provides an alternative normative Representation for parts of Digital Items that require protection through IPMP governance. This Representation is termed the IPMP Digital Item Declaration Language (IPMP DIDL), and defines governed XML elements corresponding to entities in the DID model. Each of these IPMP DIDL elements is intended to link a corresponding DIDL element (which may be encrypted) with information about the governance, so that the Digital Item or part of Digital Item thus represented is used in accordance with the Digital Item author’s wishes.
For each entity in the DID model, an IPMP DIDL element is provided as a protected Representation of that entity, derived from the abstract DID model types as defined in the DID model schema in ISO/IEC 21000-2. The relationship between the schemas for IPMP DIDL, DIDL and the DID model is shown below.
Figure 1 Schema relationship between DID model, DIDL and IPMP DIDL
As both IPMP DIDL elements and DIDL elements extend abstract types defined for the DID model, they are interchangeable within a Digital Item. As the IPMP DIDL schema imports the DIDL schema as defined in ISO/IEC 21000-2, all documents conforming to the DIDL schema are also conformant to the IPMP DIDL schema.
Each of the IPMP DIDL elements above contains identical structure.
(i) a maximum of one ipmpdidl:Identifier element, into which an appropriate identifier for the protected Representation may be placed
(ii) one ipmpdidl:Info element, into which information about the governance is placed
(iii) one ipmpdidl:Contents element, into which the governed contents is placed
This structure is shown below.
Figure 2 Structure of IPMP DIDL elements for the DID model
3.1 IPMP Info Descriptor
The description of IPMP governance and tools is required to satisfy intellectual property management and protection for a Digital Item or its parts to be accessed. The root element for IPMP Information Descriptor schema is “IPMPInfoDescriptor”, which contains a range of information related to IPMP governance and tools. Among them there are IPMP Tool information, which includes ToolDescription directly described within the descriptor or through reference and initialization settings for such tool, different level Rights description of governance of the usage for IPMP Tool or content, and the associated digital signature. The elements representing the information that may be contained in the IPMP Information Descriptor are specified by the following subclauses.
3.2 IPMP General Info Descriptor
The purpose of this clause is to describe the XML elements for representing general information about IPMP tools and rights expressions relating to a complete DID.
The IPMPGeneralInfoDescriptor element and its associated elements defined in this clause are used to communicate general information relating to a complete Digital Item. The elements representing the information that may be contained in the IPMP General Information Descriptor are specified by the following subclauses.
4 Examples of use
Processing of a governed Digital Item operate within a governed environment that protects the governed IPMP DIDL elements against unauthorised access.
IPMP DIDL elements are processed according to information defined in the ipmpdidl:Info child element.
DIDL structure can be protected by encapsulation in an IPMP DIDL element corresponding to the head element of the DIDL structure.
It is expected that processing will enforce the persistent nature of governance and not provide an ungoverned version of the Digital Item outside the secure environment at any time.
Figure 4 IPMP DIDL processing example
This can further be illustrated using an example:
<Resource ref="myPicture.png" mimeType="image/png"/>
<p class="MsoNormal" style="line-height: normal; </p> <div style=" border:="" 1.0pt="" solid="" windowtext;="" padding-left:="" 4.0pt;="" padding-right:="" padding-top:="" 1.0pt;="" padding-bottom:="" background:="" #e6e6e6"="">
Encapsulated in IPMP DIDL
<Resource ref="myPicture.png" mimeType="image/png"/>
The ipmpdidl:Contents may be encrypted, with a tool described in ipmpdidl:Info. In this case the structure and contents of ipmpdidl:Contents will not be visible.