encrypting and decrypting cookies asp.net

Question

hi i wanna  to know how can i encrypting and decrypting  cookies asp.net
i use cookie utility where i  create delete and read my cookie
this  is my code


    public static void CreateCookie(string CookieName, string[] keys, string[] values, bool Expired, HttpResponse res)
    {
        HttpCookie c = new HttpCookie(CookieName);
        if (keys != null)
        {
            for (int x = 0; x < keys.Length; x++)
                c.Values.Add(keys[x], values[x]);
            if (!Expired)
              
                c.Expires = DateTime.Now.AddDays(2);
        }
        else
           
            c.Expires = DateTime.Now.AddDays(-2);
        res.Cookies.Add(c);
    }

 

    public static string ReadFromCookie(string CookieName, string key, HttpRequest req)
    {
        try
        {
            return req.Cookies[CookieName][key].ToString();
        }
        catch
        {

            return null;
        }

    }

  

    public static void RemoveCookie(string CookieName, HttpResponse res)
    {
        CreateCookie(CookieName, null, null, false, res);
    }


in my login page i  create cookie by this code


 protected void btnLogin_Click(object sender, EventArgs e)
    {
     
        Member m = new Member();
        if (m.Login(Txtuser.Text, Txtpass.Text))
       {

           utility.CreateCookie("login", new string[] { "user", "pass" }, new string[] { Txtuser.Text, Txtpass.Text }, ChkReM.Checked, Response);
           Redirect(Txtuser.Text);
       }  
       else
           lblmsg.Text = "Username/password incorrect";
       }



    private void Redirect(string user)
    {

 
        if (user == "Admin")
            Response.Redirect("Admin/Admin.aspx");
 
        else
        {
            Response.Redirect("Users/UserInfo.aspx");
        }
    }

how can i encrypting and decrypting my  cookies in this code