Merge pull request #3 from paragonie-scott/patch-1

Add mb_string check for 8-bit functionality

Author: SammyK

src/Facebook/polyfills.php

@@ -28,8 +28,13 @@
 if(!function_exists('hash_equals')) {
     function hash_equals($knownString, $userString)
     {
-        $kLen = strlen($knownString);
-        $uLen = strlen($userString);
+        if (function_exists('mb_strlen')) {
+            $kLen = mb_strlen($knownString, '8bit');
+            $uLen = mb_strlen($userString, '8bit');
+        } else {
+            $kLen = strlen($knownString);
+            $uLen = strlen($userString);
+        }
         if ($kLen !== $uLen) {
             return false;
         }