diff --git a/index.php b/index.php
index a071c7a..6e8f37b 100644
--- a/index.php
+++ b/index.php
@@ -44,9 +44,9 @@ if (isset($_GET['secret']) && $_GET['secret'] === REGISTRATION_PASSWORD) {
         'nonce' => $_POST['nonce'],
         'username' => $username,
         'password' => $_POST['password'],
-        'admin' => 'notadmin'
+        'admin' => false
     ];
-    $content['mac'] = hash_hmac('sha1', $content['nonce']."\0".$content['username']."\0".$content['password']."\0".$content['admin'], REGISTRATION_SHARED_SECRET);
+    $content['mac'] = hash_hmac('sha1', $content['nonce']."\0".$content['username']."\0".$content['password']."\0".'notadmin', REGISTRATION_SHARED_SECRET);
 
     # debug
     echo '<!--';