114 Copyright © 2009 Open Geospatial Consortium, Inc.
10.6.2 GeoXACML see [23], [24], [25]
The Geospatial eXtensible Access Control Markup Language GeoXACML is a standard by the Open Geospatial Consortium Inc. OGC that defines a geo-specific
extension to XACML v2.0. It extends the XACML Policy Language by the new data type ―Geometry‖ and several geo-specific functions that allow the declaration and
enforcement of access rights that can be associated to geometric characteristics of the resource. The two extensions see [24] and [25] define particular XML encodings of a
XACML AttributeValue element of type Geometry, based on the Geography Markup Language GML. In particular, GeoXACML extension A provides support for GML2
and extension B provides support for GML3 formatted geometries.
10.7 Standards for Licensing
This section of the document provides an overview of standards, recommendations and other literature related to LicensingDigital Rights Management.
10.7.1 XrML see [26]
The eXtensible Rights Markup Language XrML is a proprietary XML dialect to express rights over digital content which is been used by Microsoft. It is not a standard and
owned by ContentGuard founded by Microsoft and Xerox which holds related US patens. XrML version 1.0 is the successor of DPRL Digital Property Rights Language
developed at Xerox PARC that defines computer work specific rights such as ―copy‖, ―backup‖, etc. Version 2.0 developed by ContentGuard was developed to be medium
independent. Version 2.1 of XrML was standardized by ISO as Part 5 of the MPEG-21 standards suite see next topic.
10.7.2 REL Mpeg REL see [27]
The Rights Expressions Language as specified in ISOIEC 21000-5 see [27] defines an XML dialect to express usage rights through tamper resistant enforceable licenses for
moving pictures MPEG files. In order to protect the owners’ assets, a Digital Rights Management System is required of which REL is one key component.
The kernel part of a license is the Rights Expression that grants defined usage rights to a particular consumer user. Because the rights of a license are typically enforced on the
user’s computer the content owner relies on the tamper resistance of the license and of the component that interprets the licensed rights. Assuming a tamper resistant license, the
meaning of the granted rights must be shared by the creator of the license typically the content owner and the software developer of the MPEG player. To ensure this, it is
vital to standardize a certain set of rights and their semantics e.g. play, print as it is done by this standard.
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10.7.3 ODRL see [28]
The Open Digital Rights Language ODRL Version 1.1 is a W3C Note that specifies an Expression Language and the representation in XML. It further defines the semantics of
core expressions.
The core entities of the ODRL Language are Assets, Rights and Parties. An Asset represents the content that is to be protected either in physical or digital form. Rights
include Permissions that are the actual usage that are allowed on the asset. The Parties represent the end user consumer and the Rights holders that typically have been
involved in the creation of the content or own it.
The standard defines in the ODRL Data Dictionary Semantics section a set of core rights and their semantics for Permissions, Constraints, Requirements, Rights Holders and
Context. This standard also provides extension points for the definition of project specific of data dictionary elements. One example given in the standard is associated to the
mobile community, where rights such as ―ring‖ or ―send‖ are relevant.
10.8 Standards for Web Services
