protected function buildQueryString(array $params, ConfigurationInterface $configuration) { $parameterList = []; foreach ($params as $key => $value) { $parameterList[] = sprintf('%s=%s', $key, rawurlencode($value)); } $parameterList[] = 'Signature=' . rawurlencode($this->buildSignature($parameterList, $configuration->getCountry(), $configuration->getSecretKey())); return implode("&", $parameterList); }