Encrypt Decrypt Cookies in Asp.net

In this article, I am explain how to Encrypt and Decrypt cookie values. 

Design Source Code:

<div>

            <asp:TextBox ID="txtvalue" runat="server" placeholder="Enter Some Text" Width="250">

            </asp:TextBox><br />

            <asp:Label runat="server" ID="lblmsg" ForeColor="Green" Font-Bold="true"></asp:Label><br />

            <asp:Button ID="btnEncrypt"

                runat="server" Text="Encrypt" OnClick="btnEncrypt_Click" />&nbsp;&nbsp;

            <asp:Button ID="btnDecrypt" runat="server" Text="Decrypt" OnClick="btnDecrypt_Click" Style="height: 26px" />

        </div>

Code Behind:

Using namespaces:

using System.Text;

using System.Web.Security;

protected void btnEncrypt_Click(object sender, EventArgs e)

{

byte[] bCookieText = Encoding.UTF8.GetBytes(txtvalue.Text);

string sEncryptedValue = Convert.ToBase64String(MachineKey.Protect(bCookieText, "ProtectCookie"));

HttpCookie oHttpCookie = new HttpCookie("NameOfCookie", sEncryptedValue);

//---- Set expiry time of cookie.

oHttpCookie.Expires.AddDays(5);

Response.Cookies.Add(oHttpCookie);

lblmsg.Text = sEncryptedValue;

}

protected void btnDecrypt_Click(object sender, EventArgs e)

{

byte[] bytes = Convert.FromBase64String(Request.Cookies["NameOfCookie"].Value);

byte[] bOutput = MachineKey.Unprotect(bytes, "ProtectCookie");

string sOutput = Encoding.UTF8.GetString(bOutput);

lblmsg.Text = sOutput;

}

For Asp.Net 4.0

Encryption:

var plaintextBytes = Encoding.UTF8.GetBytes("Jitendra Gangwar");

var encryptedValue = MachineKey.Encode(plaintextBytes, MachineKeyProtection.All);

Response.Write(encryptedValue.ToString());

Decryption:

var decryptedBytes = MachineKey.Decode(encryptedValue, MachineKeyProtection.All);

var decryptedValue = Encoding.UTF8.GetString(decryptedBytes);

Response.Write(decryptedValue);

OutPut:

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