Pemograman Kriptografi dalam VB

Berikut merupakan contoh Pemograman kriptografi dan contoh penggunaan MenuStrip pada VisualBasic:
1. Buka menu VisualBaasic, kemudian pilih New>Project>Ok
2. Dalam project tersebut buatlah Form1, Form2, dan Form3
    Pada Form1 anda buat desain MenuStrip

    Pada Form2 anda buat desain Kriptografi Caesar
    Pada Form3 anda buat desain Kriptografi Vernam

Listing Program untuk Form1
Public Class Form1

    Private Sub Form2ToolStripMenuItem_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Form2ToolStripMenuItem.Click
        Form2.MdiParent = Me
        Form2.Show()
    End Sub


    Private Sub Form3ToolStripMenuItem_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Form3ToolStripMenuItem.Click
        Form3.MdiParent = Me
        Form3.Show()
    End Sub

    Private Sub KeluarToolStripMenuItem_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles KeluarToolStripMenuItem.Click
        End
    End Sub
End Class


Listing Program untuk Form2
Public Class Form2

    Private Sub Btnenkripsi_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Btnenkripsi.Click
        Dim x As String = ""
        Dim xkalimat As String = ""
        For i = 1 To Len(plain.Text)
            x = Mid(plain.Text, i, i)
            x = Chr(Asc(x) + 3)
            xkalimat = xkalimat + x
        Next
        chiper.Text = xkalimat

        plain.Text = ""
    End Sub

    Private Sub Btnhapus_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Btnhapus.Click
        plain.Text = ""
        chiper.Text = ""
    End Sub

    Private Sub Btndeskripsi_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Btndeskripsi.Click
        Dim x As String = ""
        Dim xkalimat As String = ""
        For i = 1 To Len(chiper.Text)
            x = Mid(chiper.Text, i, i)
            x = Chr(Asc(x) - 3)
            xkalimat = xkalimat + x
        Next
        plain.Text = xkalimat
    End Sub

    Private Sub Form2_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load

    End Sub
End Class


Listing Program untuk Form3
Public Class Form3

   
    Private Sub Form3_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
        plainteks.Text = ""
        kunci.Text = ""
        chiperteks.Text = ""
    End Sub

    Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
        Dim j As Integer
        Dim jum As Integer
        Dim sKey As String
        Dim nKata As Integer
        Dim nKunci As Integer
        Dim sKata As String
        Dim sPlain As String = ""
        Dim nEnc As Integer
        j = 0
        sKata = plainteks.Text
        jum = Len(sKata)
        sKey = kunci.Text
        For i = 1 To jum
            If j = Len(sKey) Then
                j = 1
            Else
                j = j + 1
            End If
            nKata = Asc(Mid(sKata, i, 1)) - 65
            nKunci = Asc(Mid(sKey, j, 1)) - 65
            nEnc = ((nKata + nKunci) Mod 26)
            sPlain = sPlain & Chr((nEnc) + 65)
        Next (i)
        chiperteks.Text = sPlain
    End Sub

    Private Sub plainteks_KeyPress(ByVal sender As Object, ByVal e As System.Windows.Forms.KeyPressEventArgs) Handles plainteks.KeyPress
        e.KeyChar = UCase(e.KeyChar)
        Dim tombol As Integer = Asc(e.KeyChar)
        If Not (((tombol >= 65) And (tombol <= 90)) Or (tombol = 8)) Then
            e.Handled = True
        End If
    End Sub

    Private Sub kunci_KeyPress(ByVal sender As Object, ByVal e As System.Windows.Forms.KeyPressEventArgs) Handles kunci.KeyPress
        e.KeyChar = UCase(e.KeyChar)
        Dim tombol As Integer = Asc(e.KeyChar)
        If Not (((tombol >= 65) And (tombol <= 90)) Or (tombol = 8)) Then
            e.Handled = True
        End If
    End Sub
End Class

3. Untuk meliat hasilnya tekan F5
Maka hasilnya sebagai berikut:
Untuk Kriptografi Cesar

Untuk Kriptografi Vernam