'Deskripsi: Mengencrypt/decrypt suatu file teks menjadi file teks yang
'           lainnya dengan menggunakan password.
'Pembuat  : Masino Sinaga (admin@masinosinaga.com)
'Diupload : Rabu, 22 Mei 2002
'Persiapan: 1. Buat 1 Project baru dengan 1 Form dan 1 RichTextBox.
'           2. Beri nama RichTextBox dengan "rtfEncDec".
'           3. Copy-kan coding berikut ke dalam editor form ybt.
'---------------------------------------------------------------------

'Pada contoh ini, nama file default telah tersedia ketika
'kotak dialog InputBox ditampilkan. Klik saja OK tanpa
'mengganti nama file yang telah terisi di InputBox tersebut.
'Untuk mencoba ulang, hapus file Masino.txt, Masino1.txt,
'dan file Sinaga.txt yang terbentuk di direktori program ini...

Sub FileEncodeAndDecode(InputFile As String, _
                      OutputFile As String, _
                      PasswordKey As String)
  Dim temp As Single
  Dim Char As String * 1
  Dim XORMask As Single
  Dim temp1 As Integer
  Open InputFile For Binary As #1
  Open OutputFile For Binary As #2
  For x = 1 To Len(PasswordKey)
      temp = Asc(Mid$(PasswordKey, x, 1))
      For y = 1 To temp
          temp1 = Rnd
      Next y
      Randomize temp1
  Next x
  Counter = 0
  For z = 1 To FileLen(InputFile)
      XORMask = Int(Rnd * 256)
      Get 1, , Char
      Char = Chr$((Asc(Char) Xor XORMask))
      Put 2, , Char
      Counter = Counter + 1
      If Counter > Len(PasswordKey) Then Counter = 1
      For x = 1 To (Asc(Mid$(PasswordKey, Counter, 1)) * 2)
          temp = Rnd
      Next x
  Next z
  Close #1
  Close #2
  'Tampilkan hasilnya ke rtfEncDec...
  Open OutputFile For Binary As #3
     rtfEncDec.Text = Input(LOF(3), 3)
  Close #3
End Sub

Private Sub Command1_Click()
Dim InputFile As String
  Dim OutputFile As String
  Dim PasswordKey As String
  On Error GoTo Pesan
  'Jika file Masino.txt sudah ada dan file Sinaga.txt belum
  If Dir(App.Path & "\Masino.txt") <> "" And _
     Dir(App.Path & "\Sinaga.txt") = "" Then
     InputFile = InputBox("Masukkan nama file yang akan " & _
                       "di-encrypt/decrypt:", _
                       "File Sumber", "Masino.txt")
     If StrPtr(InputFile) = 0 Or InputFile = "" Then Exit Sub
  'Jika file Masino.txt dan Sinaga.txt sudah ada
  ElseIf Dir(App.Path & "\Masino.txt") <> "" And _
     Dir(App.Path & "\Sinaga.txt") <> "" Then
     InputFile = InputBox("Masukkan nama file yang akan " & _
                       "di-encrypt/decrypt:", _
                       "File Sumber", "Sinaga.txt")
     If StrPtr(InputFile) = 0 Or InputFile = "" Then Exit Sub
  End If
  Open App.Path & "\" & InputFile For Binary As #1
     rtfEncDec.Text = Input(LOF(1), 1)
  Close #1

  'Jika file Masino.txt sudah ada dan file Sinaga.txt belum
  If Dir(App.Path & "\Masino.txt") <> "" And _
     Dir(App.Path & "\Sinaga.txt") = "" Then
     OutputFile = InputBox("Masukkan nama file hasil " & _
                        "encrypt/decrypt: ", _
                        "File Tujuan", "Sinaga.txt")
     If StrPtr(OutputFile) = 0 Or OutputFile = "" Then Exit Sub
  'Jika file Masino.txt dan Sinaga.txt sudah ada
  ElseIf Dir(App.Path & "\Masino.txt") <> "" And _
     Dir(App.Path & "\Sinaga.txt") <> "" Then
     OutputFile = InputBox("Masukkan nama file hasil " & _
                        "encrypt/decrypt: ", _
                        "File Tujuan", "Masino1.txt")
     If StrPtr(OutputFile) = 0 Or OutputFile = "" Then Exit Sub
  End If

  PasswordKey = InputBox("Masukkan password:", _
                         "Password", "masinosinaga")

  Call FileEncodeAndDecode(App.Path & "\" & InputFile, _
                           App.Path & "\" & OutputFile, _
                           PasswordKey)

  MsgBox "Berhasil di-encrypt/decrypt ke " & OutputFile, _
         vbInformation, "Encrypt/Decrypt OK"

  End
  Exit Sub
Pesan:
  MsgBox Err.Number & " - " & Err.Description


End Sub

Private Sub Form_Load()
BuatFileTeks  'Buat file teks pada permulaan aplikasi ini
rtfEncDec.RightMargin = rtfEncDec.Width + 500
End Sub

Sub BuatFileTeks()
Open App.Path & "\Masino.txt" For Output As #1
     Print #1, "Testing membuat file teks..."
     Print #1, "Isinya akan digunakan untuk encode/decode"
     Print #1, "-----------------------------------------"
     Print #1, "Masino Sinaga"
     Print #1, "Asrama Melati 219 Puslatpos"
     Print #1, "Jalan Terusan Sari Asih 54 Bandung 40151"
Close #1
End Sub