SAML2 Profiles for PIV Subjects and Backend Attribute Exchange

Accordingly, the federal government requires a standard mechanism for 
Relying Parties to obtain PIV Cardholder information (User Attributes), 
which are available off-card, directly from the authoritative source 
(Attribute Authority). The authoritative source is the PIV Card Issuing 
Agency, which is the agency that issued the PIV Card to the PIV 
Cardholder. The exchange of these User Attributes between backend 
systems is known as “Backend Attribute Exchange” (BAE). The 
architectural vision for the BAE can be found at IDManagement.gov 
(Direct link to "Backend Attribute Exchange Architecture and Interface 
Specification 
<http://www.aniltj.com/blog/ct.ashx?id=b2bc2fde-1df9-4173-a711-046639062f19&url=http%3a%2f%2fwww.smart.gov%2fawg%2fdocuments%2fBackendArchitectureInterfaceSpec.pdf>" 
- PDF).

http://www.aniltj.com/blog/2009/06/06/SAML2ProfilesForPIVSubjectsAndBackendAttributeExchange.aspx