4.4.1 Assertion Parameters

Policy assertion parameters are the opaque payload of an assertion. Parameters carry additional useful information for engaging the behavior described by an assertion and are preserved through policy processing such as normalize, merge and policy intersection. Requesters may use policy intersection to select a compatible policy alternative for an interaction. Assertion parameters do not affect the outcome of policy intersection unless the assertion specifies domain specific processing for policy intersection.

 

In the XML representation of a policy assertion, the child elements and attributes of the assertion excluding child elements and attributes from the policy language namespace name are the assertion parameters.

 

Good practice: Assertion parameters

An assertion author should represent useful (or additional) information necessary for engaging the behavior represented by a policy assertion as assertion parameters.

 

In the example below, sp:Body and sp:Header elements are the two assertion parameters of the sp:SignedParts policy assertion (this assertion requires the parts of a message to be protected). These two parameters identify the parts of a wire message that should be protected. These parameters carry additional useful information for engaging the behavior.

 

Example 4-1. Policy Assertion with Assertion Parameters

<Policy>
  <sp:SignedParts>
    <sp:Body />
    <sp:Header />
  </sp:SignedParts>
  
</Policy>