<samlp:RequestedAuthnContext xmlns:samlp="urn:oasis:names:tc:SAML:2.0:protocol" Comparison="exact">
  <saml:AuthnContextDeclRef xmlns:saml="urn:oasis:names:tc:SAML:2.0:assertion">https://example.org/relative/path/to/document.xml</saml:AuthnContextDeclRef>
</samlp:RequestedAuthnContext>