diff --git a/phpseclib/Crypt/Common/SymmetricKey.php b/phpseclib/Crypt/Common/SymmetricKey.php
index 888a7e9b..b329087f 100644
--- a/phpseclib/Crypt/Common/SymmetricKey.php
+++ b/phpseclib/Crypt/Common/SymmetricKey.php
@@ -481,7 +481,7 @@ abstract class SymmetricKey
      *
      * - ofb
      *
-     * @param int $mode
+     * @param string $mode
      * @access public
      * @throws \InvalidArgumentException if an invalid / unsupported mode is provided
      */
@@ -1795,7 +1795,7 @@ abstract class SymmetricKey
      * If the preferred crypt engine is not available the fastest available one will be used
      *
      * @see self::__construct()
-     * @param int $engine
+     * @param string $engine
      * @access public
      */
     public function setPreferredEngine($engine)