code: public static boolean fixSalt(Document doc) {
  	Element root = doc.getDocumentElement();
  	String salt = root.getAttribute("salt");
  	if (StringUtil.isEmpty(salt, true) || !Decision.isUUId(salt)) {
  	    // create salt
  	    root.setAttribute("salt", CreateUUID.invoke());
  	    return true;
  	}
  	return false;
      }
docs: make sure every context has a salt