diff --git a/phpseclib/File/X509.php b/phpseclib/File/X509.php
index 5f1f5b68..fa67bb1c 100644
--- a/phpseclib/File/X509.php
+++ b/phpseclib/File/X509.php
@@ -311,7 +311,7 @@ class X509
      * @var int
      * @access private
      */
-    var $recur_limit = 5;
+    static $recur_limit = 5;
 
     /**
      * Default Constructor.
@@ -2119,7 +2119,7 @@ class X509
      * @access private
      * @return bool|string
      */
-    function _fetchURL($url)
+    static function _fetchURL($url)
     {
         $parts = parse_url($url);
         $data = '';
@@ -2189,7 +2189,7 @@ class X509
             return false;
         }
 
-        $cert = $this->_fetchURL($url);
+        $cert = static::_fetchURL($url);
         if (!is_string($cert)) {
             return false;
         }
@@ -2255,7 +2255,7 @@ class X509
             return null;
         }
 
-        if ($count == $this->recur_limit) {
+        if ($count == self::$recur_limit) {
             return false;
         }
 
@@ -2424,9 +2424,9 @@ class X509
      * @param int $count
      * @access public
      */
-    function setRecurLimit($count)
+    static function setRecurLimit($count)
     {
-        $this->recur_limit = $count;
+        self::$recur_limit = $count;
     }
 
     /**
diff --git a/tests/Unit/File/X509/X509Test.php b/tests/Unit/File/X509/X509Test.php
index 261d3e42..3e92d0c9 100644
--- a/tests/Unit/File/X509/X509Test.php
+++ b/tests/Unit/File/X509/X509Test.php
@@ -640,7 +640,7 @@ Fqfy+n5VpXOdrjic4yZ52yS5sUaq05s6ZZvnmdU=
 
     public function testAuthorityInfoAccess()
     {
-        $x509 = new File_X509();
+        $x509 = new X509();
         $x509->loadCA('-----BEGIN CERTIFICATE-----
 MIIDrzCCApegAwIBAgIQCDvgVpBCRrGhdWrJWZHHSjANBgkqhkiG9w0BAQUFADBh
 MQswCQYDVQQGEwJVUzEVMBMGA1UEChMMRGlnaUNlcnQgSW5jMRkwFwYDVQQLExB3
@@ -703,10 +703,10 @@ lV66p3Ui7pFABGc/Lv7nOyANXfLugBO8MyzydGA4NRGiS2MbGpswPCg154pWausU
 M0qaEPsM2o3CSTfxSJQQIyEe+izV3UQqYSyWkNqCCFPN
 -----END CERTIFICATE-----');
 
-        $x509->setRecurLimit(0);
+        X509::setRecurLimit(0);
         $this->assertFalse($x509->validateSignature());
 
-        $x509->setRecurLimit(5);
+        X509::setRecurLimit(5);
         $this->assertTrue($x509->validateSignature());
     }
 }