ImplementHeader.java

public class ImplementHeader implements RequestHandler<Map<String, Object>, NameEnquiryResponse> {

    public String handleRequest(Map<String, Object> eventMap, Context context) {

        context.getLogger().log("Header: " + eventMap.get("headers"));
        context.getLogger().log("Input: " + eventMap.get("body"));

        Gson gson = new Gson();
        String json = gson.toJson(eventMap.get("body"));
        String jsonHeader = gson.toJson(eventMap.get("headers"));

        JSONObject StringtoJson = new JSONObject(json);
        JSONObject HeaderStringtoJson = new JSONObject(jsonHeader);
        
        //your Unhash/authentication logic
        
          if (HeaderStringtoJson.getString("X-Auth-Signature").equals(value from your unhash/authentication logic)) {
          
          //do what you will
          return null;
          }else{
          //give header error
          return null;
          }
    }