SHASIGN OGONE

    /**
     * Génère le shasign Ogone
     * @param  array  $_parameters Ogone parameters
     * @param  string $secret_key Your ogone secret key
     * @return string Shasign
     */
    function getOgoneShasign($_parameters, $secret_key) {
      foreach($_parameters as $key => $parameter) {
        $parameters[strtoupper($key)] = strtoupper($key) . '=' . $parameter . $secret_key;
      }
      ksort($parameters);
      return sha1(implode($parameters));
    }