URL QueryString with Encryption & Decryption

URL QueryString with Encryption & Decryption

For the security concern we have to pass querystring value in encrypted mode,  and while we retrieve querystring value we need to decrypt it and use it.

Here, I mentioned..

1. Plain text encryption
2. Decryption of encrypted text
3. URL encode (System.Web.HttpUtility.UrlEncode)
4. URL decode (System.Web.HttpUtility.UrlDecode)

Here, I have mentioned URL querystring encryption and decryption...

Encryption

protected void Submit(object sender, EventArgs e)
    {
  string username = "anrorathod";
  string userid = "2279";
        string uname = HttpUtility.UrlEncode(Encrypt(username));
        string uid = HttpUtility.UrlEncode(Encrypt(userid));
        Response.Redirect(string.Format("~/newpagename.aspx?name={0}&id={1}", uname, uid));
    }

    private string Encrypt(string textToEncrypt)
    {
        string EncryptionKey = "Writeyourkeyhere-Youcanwriteanything";
        byte[] clearBytes = Encoding.Unicode.GetBytes(textToEncrypt);
        using (Aes encryptor = Aes.Create())
        {
            Rfc2898DeriveBytes pdb = new Rfc2898DeriveBytes(EncryptionKey, new byte[] { 0x49, 0x76, 0x61, 0x6e, 0x20, 0x4d, 0x65, 0x64, 0x76, 0x65, 0x64, 0x65, 0x76 });
            encryptor.Key = pdb.GetBytes(32);
            encryptor.IV = pdb.GetBytes(16);
            using (MemoryStream ms = new MemoryStream())
            {
                using (CryptoStream cs = new CryptoStream(ms, encryptor.CreateEncryptor(), CryptoStreamMode.Write))
                {
                    cs.Write(clearBytes, 0, clearBytes.Length);
                    cs.Close();
                }
                textToEncrypt = Convert.ToBase64String(ms.ToArray());
            }
        }
        return textToEncrypt;
    }

Decryption

 protected void Page_Load(object sender, EventArgs e)
    {
        if (!this.IsPostBack)
        {
   string username = Decrypt(HttpUtility.UrlDecode(Request.QueryString["name"]));
   string userid = Decrypt(HttpUtility.UrlDecode(Request.QueryString["id"]));
        }
    }

    private string Decrypt(string textToDecrypt)
    {
        string EncryptionKey = "Writeyourkeyhere-Youcanwriteanything";
        textToDecrypt = textToDecrypt.Replace(" ", "+");
        byte[] cipherBytes = Convert.FromBase64String(textToDecrypt);
        using (Aes encryptor = Aes.Create())
        {
            Rfc2898DeriveBytes pdb = new Rfc2898DeriveBytes(EncryptionKey, new byte[] { 0x49, 0x76, 0x61, 0x6e, 0x20, 0x4d, 0x65, 0x64, 0x76, 0x65, 0x64, 0x65, 0x76 });
            encryptor.Key = pdb.GetBytes(32);
            encryptor.IV = pdb.GetBytes(16);
            using (MemoryStream ms = new MemoryStream())
            {
                using (CryptoStream cs = new CryptoStream(ms, encryptor.CreateDecryptor(), CryptoStreamMode.Write))
                {
                    cs.Write(cipherBytes, 0, cipherBytes.Length);
                    cs.Close();
                }
                textToDecrypt = Encoding.Unicode.GetString(ms.ToArray());
            }
        }
        return textToDecrypt;
    }

Hope this will help you and save your time.

Enjoy !!!

:)