diff --git a/src/Ratchet/Component/WebSocket/Version/Hixie76.php b/src/Ratchet/Component/WebSocket/Version/Hixie76.php
index 4975d3d..6d79b8e 100644
--- a/src/Ratchet/Component/WebSocket/Version/Hixie76.php
+++ b/src/Ratchet/Component/WebSocket/Version/Hixie76.php
@@ -53,11 +53,11 @@ class Hixie76 implements VersionInterface {
     }
 
     public function generateKeyNumber($key) {
-        if (0 === mb_substr_count($key, ' ')) {
+        if (0 === substr_count($key, ' ')) {
             return '';
         }
 
-        $int = preg_replace('[\D]', '', $key) / mb_substr_count($key, ' ');
+        $int = (int)preg_replace('[\D]', '', $key) / substr_count($key, ' ');
 
         return (is_int($int)) ? $int : '';
     }
diff --git a/tests/Ratchet/Tests/Component/WebSocket/Version/Hixie76Test.php b/tests/Ratchet/Tests/Component/WebSocket/Version/Hixie76Test.php
index da35172..a4a3b90 100644
--- a/tests/Ratchet/Tests/Component/WebSocket/Version/Hixie76Test.php
+++ b/tests/Ratchet/Tests/Component/WebSocket/Version/Hixie76Test.php
@@ -41,9 +41,9 @@ class Hixie76Test extends \PHPUnit_Framework_TestCase {
 
     public static function KeyProvider() {
         return array(
-            array('179922739', '17  9 G`ZD9   2 2b 7X 3 /r90')
+            array(179922739, '17  9 G`ZD9   2 2b 7X 3 /r90')
           , array('', '17  9 G`ZD9   2 2b 7X 3 /r91')
-          , array('906585445', '3e6b263  4 17 80')
+          , array(906585445, '3e6b263  4 17 80')
           , array('', '3e6b263 4 17 80')
           , array('', '3e6b63 4 17 80')
           , array('', '3e6b6341780')