code: public static String prepareForExport(String descriptor) {
          Map<String, Object> tm = null;
          try {
              tm = XMLMap.getFullMap(descriptor.trim());
          } catch (Exception e) {
              M_log.warning("BasicLTIUtil exception parsing BasicLTI descriptor"
                      + e.getMessage());
              return null;
          }
          if (tm == null) {
              M_log.warning("Unable to parse XML in prepareForExport");
              return null;
          }
          XMLMap.removeSubMap(tm, "/basic_lti_link/x-secure");
          String retval = XMLMap.getXML(tm, true);
          return retval;
      }
docs: Remove fields that should not be exported