Fix doc for generateSalt.
@ -326,7 +326,7 @@ class BaseSecurity
*
* @param integer $cost the cost parameter
* @return string the random salt value.
* @throws InvalidParamException if the cost parameter is not between 4 and 30
* @throws InvalidParamException if the cost parameter is not between 4 and 31
*/
protected static function generateSalt($cost = 13)
{