diff --git a/FileCookie.php b/FileCookie.php
index 8e23a9d..1e1f6b7 100644
--- a/FileCookie.php
+++ b/FileCookie.php
@@ -26,8 +26,8 @@ class FileCookie
     public function __construct($ident, $rand)
     {
         global $conf;
-        $path = $conf['tmpdir'] . '/captcha/' . date('Y-m-d') . '/' . md5($ident . $rand) . '.cookie';
-        io_makeFileDir($path);
+        $this->path = $conf['tmpdir'] . '/captcha/' . date('Y-m-d') . '/' . md5($ident . $rand) . '.cookie';
+        io_makeFileDir($this->path);
     }
 
     /**
diff --git a/_test/HelperTest.php b/_test/HelperTest.php
index 42de482..ad37189 100644
--- a/_test/HelperTest.php
+++ b/_test/HelperTest.php
@@ -2,6 +2,7 @@
 
 namespace dokuwiki\plugin\captcha\test;
 
+use dokuwiki\plugin\captcha\FileCookie;
 use DokuWikiTest;
 
 /**
@@ -57,7 +58,8 @@ public function testCheck()
         $rand = 0;
         $code = $helper->generateCaptchaCode($helper->fixedIdent(), $rand);
 
-        $this->callInaccessibleMethod($helper, 'storeCaptchaCookie', [$helper->fixedIdent(), $rand]);
+        $cookie = new FileCookie($helper->fixedIdent(), $rand);
+        $cookie->set();
 
         // check with missing secrect -> fail
         $INPUT->set($this->getInaccessibleProperty($helper, 'field_in'), $code);
@@ -71,7 +73,7 @@ public function testCheck()
         $this->assertFalse($helper->check(true));
 
         // set the cookie but change the ID -> fail
-        $this->callInaccessibleMethod($helper, 'storeCaptchaCookie', [$helper->fixedIdent(), $rand]);
+        $cookie->set();
         $ID = 'test:fail';
         $this->assertFalse($helper->check(false));
     }
@@ -104,7 +106,8 @@ public function testCleanup()
         $this->assertEquals(array(), $dirs);
 
         // store a cookie
-        $this->callInaccessibleMethod($helper, 'storeCaptchaCookie', ['test', 0]);
+        $cookie = new FileCookie('test', 0);
+        $cookie->set();
 
         // nothing but today's data
         $dirs = glob("$path/*");
@@ -130,7 +133,7 @@ public function testCleanup()
         );
 
         // clean up
-        $helper->cleanCaptchaCookies();
+        FileCookie::clean();
 
         // nothing but today's data
         $dirs = glob("$path/*");
diff --git a/helper.php b/helper.php
index 65f1ca5..2543a27 100644
--- a/helper.php
+++ b/helper.php
@@ -194,7 +194,8 @@ protected function generateMagicCode($ident, $rand)
     {
         $ident = hexdec(substr(md5($ident), 5, 5)); // use part of the md5 to generate an int
         $rand *= 0xFFFFF; // bitmask from the random number
-        return md5($rand ^ $ident); // combine both values
+        $comb = (int) $rand ^ $ident; // combine both values
+        return md5($comb);
     }
 
     /**