public string md5(string str, int code)    {        if (code == 16) //16位MD5加密（取32位加密的9~25字符）        {            return System.Web.Security.FormsAuthentication.HashPasswordForStoringInConfigFile(str, "MD5").ToLower().Substring(8, 16);        }        if (code == 32) //32位加密        {            return System.Web.Security.FormsAuthentication.HashPasswordForStoringInConfigFile(str, "MD5").ToLower();        }        return "00000000000000000000000000000000";    }