dkSig.setExternalKey(encrKey.getEphemeralKey(), encrKey.getId());
dkSig.prepare(doc, secHeader);
dkSig.setParts(sigParts);
List<Reference> referenceList = dkSig.addReferencesToSign(sigParts, secHeader);
//Do signature
dkSig.appendDKElementToHeader(secHeader);
dkSig.computeSignature(referenceList, false, null);