code: function(config) {
        config = config || {};
        config.mode = mode;
        this.setSecret(config.secret);
        this.setId(config.id);
        this.setApp(config.app);
        this.setUsername(config.username);
        this.setPassword(config.password);
        Header.call(this, config);
      }
docs: The constructor
  
  @param {Object} config The config options
  @param {Boolean} [config.reply = false] True if the header if of a server reply
  @param {String} config.sid The session identifier
  @param {Date} config.date The date
  @param {String} config.key The private RSA key
  @param {String} config.cert The public X.509 cert
  @param {String} config.encoderCert The public X.509 cert of the encoder and signer of the header
  @param {String} config.secret The secret AES shared key in Base64 format
  @param {String} config.id The id (uuid) assigned to the client
  @param {String} config.app The app (uuid) assigned to the application that the client want to use
  @param {String} config.username The username for the browser login
  @param {String} config.password The password for the browser login
  @constructor