Belajar Visual Basic

Function EncDec(inData As Variant, Optional inPW As Variant = “”) As Variant
     On Error Resume Next
     Dim arrSBox(0 To 255) As Integer
     Dim arrPW(0 To 255) As Integer
     Dim Bi As Integer, Bj As Integer
     Dim mKey As Integer
     Dim i As Integer, j As Integer
     Dim x As Integer, y As Integer
     Dim mCode As Byte, mCodeSeries As Variant
   
     EncDec = “”
     If Trim(inData) = “” Then
         Exit Function
     End If
   
     If inPW <> “” Then
         j = 1
         For i = 0 To 255
             arrPW(i) = Asc(Mid$(inPW, j, 1))
             j = j + 1
             If j > Len(inPW) Then
                  j = 1
             End If
         Next i
     Else
         For i = 0 To 255
             arrPW(i) = 0
         Next i
     End If
    
     For i = 0 To 255
         arrSBox(i) = i
     Next i
    
     j = 0
     For i = 0 To 255
         j = (arrSBox(i) + arrPW(i)) Mod 256
         x = arrSBox(i)
         arrSBox(i) = arrSBox(j)
         arrSBox(j) = x
     Next i
    
     mCodeSeries = “”
     Bi = 0: Bj = 0
     For i = 1 To Len(inData)
         Bi = (Bi + 1) Mod 256
         Bj = (Bj + arrSBox(Bi)) Mod 256
         ‘ Tukar
         x = arrSBox(Bi)
         arrSBox(Bi) = arrSBox(Bj)
         arrSBox(Bj) = x

         ’siapkan kunci untuk XOR
         mKey = arrSBox((arrSBox(Bi) + arrSBox(Bj)) Mod 256)

         ‘gunakan operasi XOR
         mCode = Asc(Mid$(inData, i, 1)) Xor mKey
         mCodeSeries = mCodeSeries & Chr(mCode)
     Next i
     EncDec = mCodeSeries
End Function

Private Sub Form_Load()
  Dim Encrypt As String, Decrypt As String
 
  Encrypt = EncDec(“admin”, “win”)
  Decrypt = EncDec(“™D`­>”, “win”)
  MsgBox “Hasil enkripsi : ” & Encrypt & _
    vbCrLf & “Hasil dekripsi : ” & Decrypt
  End
End Sub