Mengencrypt/decrypt suatu file teks menjadi file teks yang lainnya dengan menggunakan password.
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
