This tutorial will show how we can create a method
that provides quick and easy string encryption and decryption for our
less sensitive data. Not recommended for highly personal data. VB.NET.
Simple String Encryption in ASP.NET and VB
This tutorial will show how we can create a method
that provides quick and easy string encryption and decryption for our
less sensitive data. Not recommended for highly personal data. VB.NET
Data Protection is a must these days, and if we are able to
encrypt our data easily, it makes a big difference. This tutorial will
show how we can create a simple method that will allow us to encrypt
small amounts of data. The method uses an ASCii swap process, so it is
not the most secure way of encrypting data, but it is very quick and
easy to do for small amounts of data. What's more, the same method will
also decrypt the data!
We start off our Default.aspx page in Visual Studio. We will add two
textboxes and two buttons to it. We will set the second textbox and
button to be invisible on page load:
<form id="form1" runat="server">
<asp:TextBox ID="txtText" runat="server"></asp:TextBox><br />
<asp:Button ID="butSubmit" runat="server" Text="Encrypt" OnClick="butSubmit_Click" /><br />
<asp:TextBox ID="txtResult" runat="server" Visible="false"></asp:TextBox>
<asp:Button ID="butDecrypt" runat="server" Text="Decrypt" Visible="false" OnClick="butDecrypt_Click" />
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One textbox and button will be used to encrypt data, and the other
will be used to decrypt the data. From the code snippet above, you can
see that we have already declared our onclick event handlers. The code
behind for both buttons is as follows:
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Protected Sub butSubmit_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles butSubmit.Click
txtResult.Text = SimpleEncrypt(txtText.Text)
txtResult.Visible = True
butDecrypt.Visible = True
txtText.Visible = False
butSubmit.Visible = False
End Sub
Protected Sub butDecrypt_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles butSubmit.Click
txtText.Text = SimpleEncrypt(txtResult.Text)
txtText.Visible = True
butSubmit.Visible = True
txtResult.Visible = False
butDecrypt.Visible = False
End Sub
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Both are identical; both buttons call the same method. This is
because the method itself knows when to encrypt and when to decrypt,
you will see how shortly. The buttons also show and hide the other
elements, depending on if the data is being encrypted or decrypted.
Now if we take a look at the method, we will see how the encryption is performed:
Public Function SimpleEncrypt(ByVal TheText As String) As String
Dim tempChar As String = Nothing
Dim i As Integer = 0
For i = 1 To TheText.Length
If ToInt32(TheText.Chars(i - 1)) < 128 Then
tempChar = System.Convert.ToString(ToInt32(TheText.Chars(i - 1)) + 100)
ElseIf ToInt32(TheText.Chars(i - 1)) > 128 Then
tempChar = System.Convert.ToString(ToInt32(TheText.Chars(i - 1)) - 100)
End If
TheText = TheText.Remove(i - 1, 1).Insert(i - 1, (CChar(ChrW(tempChar))).ToString())
Next i
Return TheText
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The method simply loops through each character in the string
provided by the user and alters it's Unicode value by adding 100 to it,
which outputs underadable text. The method then detects encrypted data
by checking each character to see if its Unicode value is above 128 -
and if it is, it will subtract the 100 it has previously added, thus
returning it to its original value and making it readable again. Now if
we run this, we should be able to encrypt and decrypt any type of
string. The full code-behind is as follows:
Imports System.Convert
Partial Class _Default
Inherits System.Web.UI.Page
Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
End Sub
Public Function SimpleEncrypt(ByVal TheText As String) As String
Dim tempChar As String = Nothing
Dim i As Integer = 0
For i = 1 To TheText.Length
If ToInt32(TheText.Chars(i - 1)) < 128 Then
tempChar = System.Convert.ToString(ToInt32(TheText.Chars(i - 1)) + 100)
ElseIf ToInt32(TheText.Chars(i - 1)) > 128 Then
tempChar = System.Convert.ToString(ToInt32(TheText.Chars(i - 1)) - 100)
End If
TheText = TheText.Remove(i - 1, 1).Insert(i - 1, (CChar(ChrW(tempChar))).ToString())
Next i
Return TheText
End Function
Protected Sub butSubmit_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles butSubmit.Click
txtResult.Text = SimpleEncrypt(txtText.Text)
txtResult.Visible = True
butDecrypt.Visible = True
txtText.Visible = False
butSubmit.Visible = False
End Sub
Protected Sub butDecrypt_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles butSubmit.Click
txtText.Text = SimpleEncrypt(txtResult.Text)
txtText.Visible = True
butSubmit.Visible = True
txtResult.Visible = False
butDecrypt.Visible = False
End Sub
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