In cryptography, a substitution cipher is a method of encoding by which units of plaintext are replaced with ciphertext, according to a regular system; the "units" may be single letters (the most common), pairs of letters, triplets of letters, mixtures of the above, and so forth. The receiver deciphers the text by performing an inverse substitution.
There are a number of different types of substitution cipher. If the cipher operates on single letters, it is termed a simple substitution cipher; a cipher that operates on larger groups of letters is termed polygraphic. A monoalphabetic cipher uses fixed substitution over the entire message, whereas a polyalphabetic cipher uses a number of substitutions at different positions in the message, where a unit from the plaintext is mapped to one of several possibilities in the ciphertext and vice versa. http://en.wikipedia.org/wiki/Substitution_cipher
** Click here for 3DES (Data Encryption & Decryption)
Shown below is the screen shot and source code for each module respectively of a data encryption and decryption system using simple substitution cipher.
Screen shot for 'Start Page'
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** Click here for 3DES (Data Encryption & Decryption)
Shown below is the screen shot and source code for each module respectively of a data encryption and decryption system using simple substitution cipher.
Screen shot for 'Start Page'
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Source code for 'Start Page'
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Public Class Start_Page
Private Sub encrypt_Click(ByVal
sender As System.Object, ByVal e As
System.EventArgs) Handles encrypt.Click
frmEncrypt.ShowDialog()
End Sub
Private Sub Start_Page_Resize(ByVal
sender As Object,
ByVal e As
System.EventArgs) Handles Me.Resize
Me.Height
= 357
Me.Width
= 634
End Sub
Private Sub decrypt_Click(ByVal
sender As System.Object, ByVal e As
System.EventArgs) Handles decrypt.Click
frmDecrypt.ShowDialog()
End Sub
Private Sub
exitt_Click(ByVal sender As System.Object, ByVal
e As System.EventArgs) Handles
exitt.Click
Me.Close()
End Sub
End Class
Screen shot for 'frmEncrypt'
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Source code for 'frmEncrypt'
-----------------------------
Public Class frmEncrypt
Private Sub cmdopen_Click(ByVal
sender As System.Object, ByVal e As
System.EventArgs) Handles cmdopen.Click
ofd.ShowDialog()
txtfilename.Text = ofd.FileName
Try
txtoriginal.Text = My.Computer.FileSystem.ReadAllText(ofd.FileName)
Catch
ex As Exception ' Bad practice (catching exception)
Dim
a As String
a = MessageBox.Show("File not found, Check the file name and try
again", "Encryption",
MessageBoxButtons.OK, MessageBoxIcon.Exclamation)
cmdopen.Focus()
txtfilename.Text = String.Empty
End Try
End Sub
Private Sub
cmdsaveencrypt_Click(ByVal sender As System.Object, ByVal
e As System.EventArgs) Handles
cmdsaveencrypt.Click
If
txtEncrypted.Text = String.Empty Then
Dim
a As String
a = MessageBox.Show("File not found; Check to make sure the file has
been encrypted", "Encryption",
MessageBoxButtons.OK, MessageBoxIcon.Exclamation)
cmdopen.Focus()
Else
Dim
inn As String
inn = InputBox("Enter file name")
If inn = "" Then
Else
System.IO.File.WriteAllText("'" & inn & " ' ", txtEncrypted.Text)
Dim
haha As String
haha = MessageBox.Show("File saved", "Encryption",
MessageBoxButtons.OK, MessageBoxIcon.Information)
txtEncrypted.Text = String.Empty
txtoriginal.Text = String.Empty
txtfilename.Text = ""
End
If
End If
End Sub
Private Sub Button2_Click(ByVal
sender As System.Object, ByVal e As
System.EventArgs) Handles cmdencrypt.Click
Try
txtEncrypted.Text = My.Computer.FileSystem.ReadAllText(ofd.FileName).ToLower.Replace("a", "/").Replace("b", "\").Replace("c", "*").Replace("d", "-").Replace("e", "+").Replace("f", "^").Replace("g", "<").Replace("h", ">").Replace("i", "!").Replace("j", "~").Replace("k", "@").Replace("l", "#").Replace("m", "$").Replace("n", "%").Replace("o", "&").Replace("p", "(").Replace("q", ")").Replace("r", "{").Replace("s", "}").Replace("t", "[").Replace("u", "]").Replace("v", "=").Replace("w", "'").Replace("x", "`").Replace("y", ";").Replace("z", ":").Replace("1", "|").Replace("2", "_")
'-------substitution
area--a.k.a replacement cipher------
Catch
ex As Exception
Dim
w As String
w = MessageBox.Show("Check to make sure a file is selected",
"Encryption",
MessageBoxButtons.OK, MessageBoxIcon.Information)
cmdopen.Focus()
End Try
End Sub
Private Sub cmdclose_Click(ByVal
sender As System.Object, ByVal e As
System.EventArgs) Handles cmdclose.Click
Me.Close()
End Sub
Private Sub frmEncrypt_Resize(ByVal
sender As Object,
ByVal e As
System.EventArgs) Handles Me.Resize
Me.Height
= 534
Me.Width
= 970
End Sub
Private Sub cmdclear_Click(ByVal
sender As System.Object, ByVal e As
System.EventArgs) Handles cmdclear.Click
txtoriginal.Text = ""
txtEncrypted.Text = ""
txtfilename.Text = ""
cmdopen.Focus()
End Sub
Private Sub frmEncrypt_Load(ByVal
sender As System.Object, ByVal e As
System.EventArgs) Handles MyBase.Load
End Sub
End Class
Screen shot for 'frmDecrypt'
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Screen shot for 'frmDecrypt'
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Source code for 'frmDecrypt'
-----------------------------
Public Class frmDecrypt
Private Sub cmdopen_Click(ByVal
sender As System.Object, ByVal e As System.EventArgs)
Handles cmdopen.Click
Try
OpenFileDialog1.ShowDialog()
txtfilename.Text =
OpenFileDialog1.FileName
txtoriginal.Text = My.Computer.FileSystem.ReadAllText(OpenFileDialog1.FileName)
Catch
ju As Exception
Dim
viva As String
viva = MessageBox.Show("No file selected", "Decryption", MessageBoxButtons.OK,
MessageBoxIcon.Information)
cmdopen.Focus()
txtfilename.Clear()
End Try
End Sub
Private Sub cmddecrypt_Click(ByVal
sender As System.Object, ByVal e As
System.EventArgs) Handles cmddecrypt.Click
If
txtoriginal.Text = "" Then
Dim
viv As String
viv = MessageBox.Show("No file selected for decryption", "Decryption", MessageBoxButtons.OK,
MessageBoxIcon.Information)
Else
txtdecrypted.Text = My.Computer.FileSystem.ReadAllText(OpenFileDialog1.FileName).ToLower.Replace("/", "a").Replace("\", "b").Replace("*", "c").Replace("-", "d").Replace("+", "e").Replace("^", "f").Replace("<", "g").Replace(">", "h").Replace("!", "i").Replace("~", "j").Replace("@", "k").Replace("#", "l").Replace("$", "m").Replace("%", "n").Replace("&", "o").Replace("(", "p").Replace(")", "q").Replace("{", "r").Replace("}", "s").Replace("[", "t").Replace("]", "u").Replace("=", "v").Replace("'", "w").Replace("`", "x").Replace(";", "y").Replace(":", "z").Replace("|", "1").Replace("_", "2")
'--.....decryption
arena....don't touch--------------------------------
End If
End Sub
Private Sub cmdexit_Click(ByVal
sender As System.Object, ByVal e As
System.EventArgs) Handles cmdexit.Click
Me.Close()
End Sub
Private Sub frmDecrypt_Resize(ByVal
sender As Object,
ByVal e As
System.EventArgs) Handles Me.Resize
Me.Height
= 534
Me.Width
= 970
End Sub
Private Sub cmdsavedecrypt_Click(ByVal
sender As System.Object, ByVal e As
System.EventArgs) Handles cmdsavedecrypt.Click
If
txtdecrypted.Text = String.Empty Then
Dim
a As String
a = MessageBox.Show("File not found", "Decryption", MessageBoxButtons.OK,
MessageBoxIcon.Exclamation)
cmdopen.Focus()
Else
Dim
oops As String
oops = InputBox("Enter file name")
If
oops = "" Then
' Do nothing
Else
System.IO.File.WriteAllText("'" & oops & " ' ", txtdecrypted.Text)
Dim
ha As String
ha = MessageBox.Show("File saved", "Decryption",
MessageBoxButtons.OK, MessageBoxIcon.Information)
txtdecrypted.Text = String.Empty
txtoriginal.Text = String.Empty
txtfilename.Text = ""
'GoTo
k
End
If
End If
End Sub
Private Sub btnclear_Click(ByVal
sender As System.Object, ByVal e As
System.EventArgs) Handles btnclear.Click
txtoriginal.Text = ""
txtdecrypted.Text = ""
txtfilename.Text = ""
cmdopen.Focus()
End Sub
End Class
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Click here for Tripple DES (Data Encryption & Decryption)
============================================
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Click here for Tripple DES (Data Encryption & Decryption)
============================================
