diff --git a/src/Ratchet/Wamp/WampConnection.php b/src/Ratchet/Wamp/WampConnection.php
index a12b162..8364efd 100644
--- a/src/Ratchet/Wamp/WampConnection.php
+++ b/src/Ratchet/Wamp/WampConnection.php
@@ -17,7 +17,7 @@ class WampConnection extends AbstractConnectionDecorator {
         parent::__construct($conn);
 
         $this->WAMP            = new \StdClass;
-        $this->WAMP->sessionId = md5(uniqid(mt_rand(), true));
+        $this->WAMP->sessionId = str_replace('.','',uniqid(mt_rand(), true));
         $this->WAMP->prefixes  = array();
 
         $this->send(json_encode(array(WAMP::MSG_WELCOME, $this->WAMP->sessionId, 1, \Ratchet\VERSION)));