wiki:TIEDABACDemo

Version 1 (modified by faber@isi.edu, 10 years ago) (diff)

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ABAC Authorization Control Illustrative Example

ABAC is an attribute-based authorization system that combines attributes using a simple reasoning system to provide authorization that

  • Expresses delegation and other authorization models efficiently and scalably
  • Allows access requesters and granters to control how much information they reveal
  • Provides auditing information that includes both the decision and reasoning
  • Supports multiple authentication frameworks as entry points into the attribute space

ABAC Model

In ABAC, principals are created by authenticating to the system. A principal can be an individual (researcher, user) or larger authority (GPO, university). Prinicpals can use a range of systems to authenticate themselves. A principal can be the subject of authorization decisions and have attributes asserted about it by other principals.

An attribute is an assertion by one principal that another has a given property. The University of Southern California (a principal) may assert that Ted Faber (a principal) is a staff member (attribute). The attributes are scoped by prinicpal. This is represented as a digitally signed assertion.

A given prinicpal may also assert rules about how attributes relate. The GPO may assert that all USC GENI staff are also GPO prototypers. That delegates authority to USC add to GPO prototypers.

Finally, a principal may delegate at one remove. The GPO may assert that any NSF PI (any principal that the NSF has asserted a PI attribute about) can designate a principal as a GENI user and that user will be a GPO GENI user. The NSF can affect GPO GENI users by creating or deleting PIs; that is, by adding or removing assertions that a particular principal is a PI. Individual PIs can also directly designate local GENI users that are also GPO GENI users as above.

Until an authorization decision needs to be made, all of these attributes (signed assertions) can be kept locally and brogght together to make the decision. Principals can also pass them around so they are available when needed. For example, when the NSF designates a PI, it may send that PI the signed attribute so that the PI can use it in authorization requests.

Visualizing ABAC Attributes

In TIED's attribute browser, we use some graphical conventions that may make these ideas easier to follow.

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