question: public static String parseSignedMessage ( HttpServletRequest request ) throws IllegalArgumentException { String queryString = request . getQueryString ( ) ; String samlRequest = HTTPTransportUtils . getRawQueryStringParameter ( queryString , SamlUtils . SAML_REQUEST_PARAMETER ) ; String samlResponse = HTTPTransportUtils . getRawQueryStringParameter ( queryString , SamlUtils . SAML_RESPONSE_PARAMETER ) ; Validate . isTrue ( samlRequest != null || samlResponse != null ) ; String signature = HTTPTransportUtils . getRawQueryStringParameter ( queryString , SamlUtils . SIGNATURE_PARAMETER ) ; String sigAlgo = HTTPTransportUtils . getRawQueryStringParameter ( queryString , SamlUtils . SIGNATURE_ALGORITHM_PARAMETER ) ; String relayState = HTTPTransportUtils . getRawQueryStringParameter ( queryString , SamlUtils . RELAY_STATE_PARAMETER ) ; if ( signature == null || sigAlgo == null ) { return null ; } StringBuilder builder = new StringBuilder ( ) ; if ( samlRequest != null ) { builder . append ( samlRequest ) ; } else { builder . append ( samlResponse ) ; } if ( relayState != null ) { builder . append ( '&' ) ; builder . append ( relayState ) ; } builder . append ( '&' ) ; builder . append ( sigAlgo ) ; String signedMessage = builder . toString ( ) ; log . debug ( "Constructed signed message {}" , signedMessage ) ; return signedMessage ; }
target:  return signed message in a http SAML request or response