Difference between revisions of "Context"

Revision as of 21:16, 31 January 2008

Introduction

This page describes the Context concept.

Definition

• A Context is a set of one or more Entities identified by a ContextId.
• Each Context is an instance of a Context Type.
• A Context may have zero or more Attributes.
• A Context has a schema that describes kinds of Entities and Attributes that an instance of this Context contains.
• Every Context has its own security and access control policy

Examples

Examples of Contexts that contain multiple Entities include: directories, informal groups, project teams, collaboration spaces, and communications systems and networks. Examples of Contexts that, at least from the point of view of the authenticated consumer, typically contain only a single Digital Subject are: driver's licenses, credit cards, business cards, and many other kinds of security devices.

HOWL

	<owl:Class rdf:ID="Context">
		<rdfs:comment>
                This instance represents the containing Context itself.
                </rdfs:comment>
	</owl:Class>

In IdAS

Consumers must be able to provide the required Digital Identity object to "open" i.e. authenticate to a Context. Once opened, the contents of the Context can be searched, read and updated to varying extents based on the authorization policy of the Context.

Footnote

Some Contexts are abstract. An example of an abstract Context would be the internet mail Context associated with the internet mail ContextId. The Digital Subjects within this Context have a SubjectId that is an email address (e.g. "foo@boo.com") within the email namespace defined by internet mail. This ContextId cannot be resolved to a physical Context because there is no globally defined set of all email addresses.

See Also

• ContextId
• Concepts

Links

• Higgins Home