byte[] secret = null;
Element secRefElement = dkt.getSecurityTokenReferenceElement();
if (secRefElement != null) {
STRParser strParser = new DerivedKeyTokenSTRParser();
strParser.parseSecurityTokenReference(
secRefElement, data, wsDocInfo, null
);
secret = strParser.getSecretKey();
} else {
throw new WSSecurityException(WSSecurityException.ErrorCode.FAILED_CHECK, "noReference");