Generate unique OTP in asp.net using C#

In this article I am going to explain how to generate unique OTP (one time password) in asp.net

Description:

OTP stand for one time password. It is a password that is valid for only one login session or transaction. It is widely used by the banks for transactions. It can be numeric as well as alphanumerical.

HTML markup:

   <fieldset style="width:420px">

    <legend><strong>OTP Example</strong></legend>

     <table>

    <tr><td>Click to Generate OTP :</td><td>

        <asp:Button ID="btnOTP" runat="server" Text="Generate OTP"/></td></tr>

     <tr><td></td><td></td></tr>

      <tr id="idotp" runat="server" visible="false"><td><strong>OTP</strong> :</td><td>

          <asp:Label ID="lblotp" runat="server"></asp:Label></td></tr>

    </table>

    </fieldset>

Generate numeric OTP

On button click write the below given to generate OTP:

C# code:

protected void btnOTP_Click(object sender, EventArgs e)

    {

        GenerateOTP();

    }

    private void GenerateOTP()

    {

        try

        {

            int length = 6;

            string numbers = "0123456789";

            Random objrandom = new Random();

            string strrandom = string.Empty;

            int noofnumbers = length;

            for (int i = 0; i < noofnumbers; i++)

            {

                int temp = objrandom.Next(0, numbers.Length);

                strrandom += temp;

            }

            lblotp.Text = strrandom;

            idotp.Visible = true;

        }

        catch (Exception ex)

        {

        }

    }