private static string Descrypt(string source, short shift)
    {
        int num = Convert.ToInt32('uffff');
        int num2 = Convert.ToInt32('');
        char[] array = source.ToCharArray();
        for (int i = 0; i < array.Length; i++)
        {
            int num3 = Convert.ToInt32(array[i]) + shift;
            if (num3 > num)
            {
                num3 -= num;
            }
            else if (num3 < num2)
            {
                num3 += num;
            }
            array[i] = Convert.ToChar(num3);
        }
        return new string(array);
    }


Webbrowser1.Url = new Uri(Descrypt("AQUI É O CODIGO ENCRIPTADO", -8) + "1.1.php", UriKind.Absolute);