diff --git a/phpseclib/Crypt/Common/AsymmetricKey.php b/phpseclib/Crypt/Common/AsymmetricKey.php
index 8bf4f8b7..569d2236 100644
--- a/phpseclib/Crypt/Common/AsymmetricKey.php
+++ b/phpseclib/Crypt/Common/AsymmetricKey.php
@@ -261,7 +261,8 @@ abstract class AsymmetricKey
     {
         if (!isset(self::$plugins[static::ALGORITHM][$format])) {
             self::$plugins[static::ALGORITHM][$format] = [];
-            foreach (glob(__DIR__ . '/../' . static::ALGORITHM . '/' . $format . '/*.php') as $file) {
+            foreach (new \DirectoryIterator(__DIR__ . '/../' . static::ALGORITHM . '/' . $format . '/') as $file) {
+                if ($file->getExtension() !== 'php') continue;
                 $name = pathinfo($file, PATHINFO_FILENAME);
                 $type = 'phpseclib\Crypt\\' . static::ALGORITHM . '\\' . $format . '\\' . $name;
                 self::$plugins[static::ALGORITHM][$format][strtolower($name)] = $type;