Querystring Encryption and Decryption

<div>

    <asp:textbox id="txtData" runat="server" />

    <br />

    <br />

    <asp:button Id="btnClick" text="Click" runat="server" onclick="dd_Click" />

</div>

using System.IO;

using System.Text;

using System.Security.Cryptography;

protected void btnClick_Click(object sender, EventArgs e)

    {

        string Data = HttpUtility.UrlEncode(Encrypt_Data(txtData.Text));

        Response.Redirect(string.Format("~/test2.aspx?Data={0}", Data));

    }

private string Encrypt_Data(string Encry_Data)

{

        string Encryp_Key = "MAKV2SPBNI99212";

        byte[] Clear_Data = Encoding.Unicode.GetBytes(Encry_Data);

        using (Aes Enc_Key = Aes.Create())

        {

            Rfc2898DeriveBytes pdb = new Rfc2898DeriveBytes(Encryp_Key, new byte[] { 0x49, 0x76, 0x61, 0x6e, 0x20, 0x4d, 0x65, 0x64, 0x76, 0x65, 0x64, 0x65, 0x76 });

            Enc_Key.Key = pdb.GetBytes(32);

            Enc_Key.IV = pdb.GetBytes(16);

            using (MemoryStream MemoryStream1 = new MemoryStream())

            {

                using (CryptoStream cs = new CryptoStream(MemoryStream1, Enc_Key.CreateEncryptor(), CryptoStreamMode.Write))

                {

                    cs.Write(Clear_Data, 0, Clear_Data.Length);

                    cs.Close();

                }

                Encry_Data = Convert.ToBase64String(MemoryStream1.ToArray());

            }

        }

        return Encry_Data;

}

<div>

        <asp:label text="Encryption Querystring data => " runat="server" /><asp:label id="lblData"  runat="server" />

    </div>

protected void Page_Load(object sender, EventArgs e)

    {

        if (!this.IsPostBack)

        {

            lblData.Text = Request.QueryString["Data"];

            string Data = Decrypt_Data(HttpUtility.UrlDecode(Request.QueryString["Data"]));

            Response.Write(" Your Quyery String Data       => " + Data);

                    }

    }

private string Decrypt_Data(string Data_Encry)

    {

        string Encryp_Key = "MAKV2SPBNI99212";

        Data_Encry = Data_Encry.Replace(" ", "+");

        byte[] Data_Encry_Bytes = Convert.FromBase64String(Data_Encry);

        using (Aes Enc_Key = Aes.Create())

        {

            Rfc2898DeriveBytes enc = new Rfc2898DeriveBytes(Encryp_Key, new byte[] { 0x49, 0x76, 0x61, 0x6e, 0x20, 0x4d, 0x65, 0x64, 0x76, 0x65, 0x64, 0x65, 0x76 });

            Enc_Key.Key = enc.GetBytes(32);

            Enc_Key.IV = enc.GetBytes(16);

            using (MemoryStream MemoryStream1 = new MemoryStream())

            {

                using (CryptoStream cs = new CryptoStream(MemoryStream1, Enc_Key.CreateDecryptor(), CryptoStreamMode.Write))

                {

                    cs.Write(Data_Encry_Bytes, 0, Data_Encry_Bytes.Length);

                    cs.Close();

                }

                Data_Encry = Encoding.Unicode.GetString(MemoryStream1.ToArray());

            }

        }

        return Data_Encry;

    }