Generate One Time Password (OTP) in Asp.net using C#, VB.NET

By: Suresh Dasari Aug 27, 2015

Introduction:

Here I will explain how to generate random one time password or otp in asp.net using c#, vb.net with example or generate unique random otp or one time password in asp.net using c#, vb.net with example or generate random alphanumeric one time password or otp in asp.net using c#, vb.net with example.

Description:

In previous articles I explained insert, update, delete in gridview with single stored procedure, jQuery gridview crud operations without postback in asp.net, gridview examples in asp.net, display images from database using handler in asp.net, generate random password in asp.net using c# and many articles relating to gridview, asp.net, c#,vb.net and jQuery. Now I will explain how to generate random alphanumeric otp or one time password in asp.net using c#, vb.net with example.

To generate random otp in asp.net open your aspx page and write the following code

<title>Generate Random Number or String or Password in Asp.net</title>

</head>

<body>

<div>

Enter Number of Characters: <asp:TextBox ID="txtCharacters" runat="server"/>

<asp:Button ID="btnGenerate" Text="Generate" runat="server"

onclick="btnGenerate_Click" /><br />

<asp:Label ID="lblResult" runat="server" ForeColor="Red" />

</div>

</form>

</body>

</html>

Now add following namespaces in code behind

C# Code

using System;

using System.Web;

After completion of adding namespaces you need to write the code like as shown below

protected void Page_Load(object sender, EventArgs e)

{

}

protected void btnGenerate_Click(object sender, EventArgs e)

{

// declare array string to generate random string with combination of small,capital letters and numbers

char[] charArr = "0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ".ToCharArray();

string strrandom = string.Empty;

Random objran = new Random();

int noofcharacters = Convert.ToInt32(txtCharacters.Text);

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

{

//It will not allow Repetation of Characters

int pos = objran.Next(1, charArr.Length);

if (!strrandom.Contains(charArr.GetValue(pos).ToString()))

strrandom += charArr.GetValue(pos);

else

i--;

}

lblResult.Text = strrandom;

}

VB.NET Code

Imports System.Web

Partial Class VBCode

Inherits System.Web.UI.Page

Protected Sub Page_Load(sender As Object, e As EventArgs)

End Sub

Protected Sub btnGenerate_Click(ByVal sender As Object, ByVal e As EventArgs)

' declare array string to generate random string with combination of small,capital letters and numbers

Dim charArr As Char() = "0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ".ToCharArray()

Dim strrandom As String = String.Empty

Dim objran As New Random()

Dim noofcharacters As Integer = Convert.ToInt32(txtCharacters.Text)

For i As Integer = 0 To noofcharacters - 1

'It will not allow Repetation of Characters

Dim pos As Integer = objran.[Next](1, charArr.Length)

If Not strrandom.Contains(charArr.GetValue(pos).ToString()) Then

strrandom += charArr.GetValue(pos)

Else

i -= 1

End If

End Sub

End Class

Demo

Generate One Time Password (OTP) in Asp.net using C#, VB.NET

Download Sample Code Attached

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6 comments :

Our DotNET said...: It's otp generation sample ?; August 27, 2015 at 9:36 PM
Suresh Dasari said...: @bhushan yes it's otp generation sample only based on your requirement you need to change charArr arrray...; August 27, 2015 at 11:08 PM
Suresh Dasari said...: If you want only numbers please change charArr array mention only numbers; August 27, 2015 at 11:09 PM
Anonymous said...: can u tell me how it will connect to gate way i mean how can we connect and generate otp?; January 16, 2017 at 10:23 PM
Unknown said...: can u tell me how it will connect to gate way i mean how can we connect and generate otp?; January 7, 2018 at 9:34 PM
Unknown said...: hi sir i want how to send the otp to email using asp.net mvc; April 26, 2018 at 5:08 AM