diff --git a/src/Bundle/ChillMainBundle/Controller/ExportController.php b/src/Bundle/ChillMainBundle/Controller/ExportController.php
index bc3f994a7..5dcd158f6 100644
--- a/src/Bundle/ChillMainBundle/Controller/ExportController.php
+++ b/src/Bundle/ChillMainBundle/Controller/ExportController.php
@@ -405,7 +405,7 @@ class ExportController extends AbstractController
             'alias' => $alias,
         ];
         unset($parameters['_token']);
-        $key = md5(uniqid(mt_rand(), false));
+        $key = md5(uniqid((string) mt_rand(), false));
 
         $this->redis->setEx($key, 3600, serialize($parameters));