Element docElement = XMLEncryptionUtil.encryptElementInDocument(responseDoc, kp.getPublic(), sk, 128, assertionQName,
true);
InputStream is = DocumentUtil.getNodeAsStream(docElement);
EncryptedAssertionType eet = sr.getEncryptedAssertion(is);
rt.addAssertion(new RTChoiceType(eet));
RTChoiceType choiceType = rt.getAssertions().get(1);
EncryptedAssertionType encryptedAssertionType = choiceType.getEncryptedAssertion();
Document eetDoc = sr.convert(encryptedAssertionType);
Element decryptedDocumentElement = XMLEncryptionUtil.decryptElementInDocument(eetDoc, kp.getPrivate());