diff --git a/src/Ratchet/Server/IoServer.php b/src/Ratchet/Server/IoServer.php
index 4db1c7b..0d18c8d 100644
--- a/src/Ratchet/Server/IoServer.php
+++ b/src/Ratchet/Server/IoServer.php
@@ -65,10 +65,10 @@ class IoServer {
      * @param  string                             $address   The address to receive sockets on (0.0.0.0 means receive connections from any)
      * @return IoServer
      */
-    public static function factory(MessageComponentInterface $component, $port = 80, $address = '0.0.0.0', $sslconf = array()) {
+    public static function factory(MessageComponentInterface $component, $port = 80, $address = '0.0.0.0', $sslconf = null) {
         $loop   = LoopFactory::create();
         $socket = new Reactor($loop);
-        if (!empty($sslconf)) {
+        if (is_array($sslconf)) {
             $socket = new SecureReactor($socket, $loop, $sslconf);
         }
         $socket->listen($port, $address);