diff --git a/phpseclib/Crypt/Hash.php b/phpseclib/Crypt/Hash.php
index 2d01807b..4825c70d 100644
--- a/phpseclib/Crypt/Hash.php
+++ b/phpseclib/Crypt/Hash.php
@@ -1322,9 +1322,10 @@ class Hash
             list($lo, $hi) = $x;
         }
 
+        $mask = -1 ^ (-1 << $shift);
         return [
-            ($hi << $shift) | (($lo >> (32 - $shift)) & (1 << $shift) - 1),
-            ($lo << $shift) | (($hi >> (32 - $shift)) & (1 << $shift) - 1)
+            ($hi << $shift) | (($lo >> (32 - $shift)) & $mask),
+            ($lo << $shift) | (($hi >> (32 - $shift)) & $mask)
         ];
     }
 
@@ -1481,7 +1482,8 @@ class Hash
      */
     private static function rotateLeft64($x, $shift)
     {
-        return ($x << $shift) | (($x >> (64 - $shift)) & ((1 << $shift) - 1));
+        $mask = -1 ^ (-1 << $shift);
+        return ($x << $shift) | (($x >> (64 - $shift)) & $mask);
     }
 
     /**