docs: public OpenPgpMessage decryptAndVerify(OpenPgpElement element, OpenPgpContact sender)
              throws SmackException.NotLoggedInException, PGPException, IOException, XmlPullParserException {
  
          OpenPgpMessage decrypted = openPgpManager.decryptOpenPgpElement(element, sender);
          if (decrypted.getState() != OpenPgpMessage.State.signcrypt) {
              throw new IllegalArgumentException("Decrypted message does appear to not be an OX message. (State: " + decrypted.getState() + ")");
          }
  
          return decrypted;
      }