Attribute-Based Authorization

SAML is being applied in a number of different ways, one of which is Attribute-based authorization.
The attribute-based authorization model has one web site communicating identity information about a subject to another web site in support of some transaction. However, the identity information may be some characteristic of the subject (such as a person's role in a B2B scenario) rather than, or in addition to, information about when and how the person was authenticated. The attribute-based authorization model is

important when the individual's particular identity is either not important, should not be shared (for privacy reasons), or is insufficient on its own.
 

See also:

- SAML Executive Overview
- SAML Technical Overview

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Courtesy:http://saml.xml.org/attribute-based-authorization