SecurityTokenReferenceType securityRef = reference.getSecurityTokenReference();
assertNotNull("Unexpected null security reference", securityRef);
String tokenTypeAttr = securityRef.getOtherAttributes().get(new QName(WSTrustConstants.WSSE11_NS, "TokenType"));
assertNotNull("Required attribute TokenType is missing", tokenTypeAttr);
assertEquals("TokenType attribute has an unexpected value", SAMLUtil.SAML2_TOKEN_TYPE, tokenTypeAttr);
KeyIdentifierType keyId = (KeyIdentifierType) securityRef.getAny().get(0);
assertEquals("Unexpected key value type", SAMLUtil.SAML2_VALUE_TYPE, keyId.getValueType());
assertNotNull("Unexpected null key identifier value", keyId.getValue());
assertEquals(assertion.getID(), keyId.getValue().substring(1));
}