WS-Policy


WS-Policy is a specification that allows web services to use XML to advertise their policies and for web service consumers to specify their policy requirements.
WS-Policy is a W3C recommendation as of September 2007.
WS-Policy represents a set of specifications that describe the capabilities and constraints of the security policies on intermediaries and end points and how to associate policies with services and end points.

Policy Assertion

Assertions can either be requirements put upon a web service or an advertisement of the policies of a web service.

Operator tags

Two "operators" are used to make statements about policy combinations:
Logically, an empty wsp:All tag makes no assertions.

Policy Intersection

If both provider and consumer specify a policy, an effective policy will be computed which usually consists of the intersection of both policies. The new policy contains those assertions made by both sides which do not contradict each other. However, synonymous assertions are considered incompatible by a policy intersection. This can easily be explained by the fact that policy intersection is a syntactic approach, which does not incorporate the semantics of the assertions. Furthermore, it ignores the assertion parameters.
Opposed to what the name might suggest, a policy intersection is not a set-intersection.

Associated specifications