diff --git a/phpseclib/Crypt/RSA.php b/phpseclib/Crypt/RSA.php
index 6af7811c..157d512b 100644
--- a/phpseclib/Crypt/RSA.php
+++ b/phpseclib/Crypt/RSA.php
@@ -2217,6 +2217,10 @@ class RSA
      */
     function _equals($x, $y)
     {
+        if (function_exists('hash_equals')) {
+            return hash_equals($x, $y);
+        }
+
         if (strlen($x) != strlen($y)) {
             return false;
         }