How To I Write Copymem Lib "Kernel32" Alias "Rtlmovememory" In Vb.Net

Private Declare Sub CopyMem Lib "kernel32" Alias "RtlMoveMemory" (Destination As Any, Source As Any, ByVal Length As Long)


Public Property Let Key(New_Value As String)

  Dim i As Long
  Dim j As Long
  Dim K As Long
  Dim dataX As Long
  Dim datal As Long
  Dim datar As Long
  Dim Key() As Byte
  Dim KeyLength As Long

  'Do nothing if the key is buffered
  If (m_KeyValue = New_Value) Then Exit Property
  m_KeyValue = New_Value
  
  'Convert the new key into a bytearray
  KeyLength = Len(New_Value)
  Key() = StrConv(New_Value, vbFromUnicode)
  
  'Create key-dependant p-boxes
  j = 0
  For i = 0 To (ROUNDS + 1)
    dataX = 0
    For K = 0 To 3
      Call CopyMem(ByVal VarPtr(dataX) + 1, dataX, 3) 'the problem is here
      dataX = (dataX Or Key(j))
      j = j + 1
      If (j >= KeyLength) Then j = 0
    Next
    m_pBox(i) = m_pBox(i) Xor dataX
  Next
  
End Property

Private Declare Sub CopyMem Lib "KERNEL32" Alias "RtlMoveMemory" (ByVal pDst As Object, ByVal pSrc As Object, ByVal ByteLen As Integer)


    Public WriteOnly Property Key() As String
           Set(ByVal Value As String)

               Dim i As Long
               Dim j As Long
               Dim K As Long
               Dim dataX As Long
               Dim datal As Long
               Dim datar As Long
               Dim Key() As Byte
               Dim KeyLength As Long

               'Do nothing if the key is buffered
               If (m_KeyValue = Value) Then Exit Property
               m_KeyValue = Value

               'Convert the new key into a bytearray
               KeyLength = Len(Value)

               Key = System.Text.Encoding.Unicode.GetBytes(Value)

               'Create key-dependant p-boxes
               j = 0

               For i = 0 To (ROUNDS + 1)
                   dataX = 0
                   For K = 0 To 3


                       CopyMem(VarPtr(dataX) + 1, dataX, 3) ' the problem is here
                       dataX = (dataX Or Key(j))
                       j = j + 1
                       If (j >= KeyLength) Then j = 0

                   Next
                   m_pBox(i) = m_pBox(i) Xor dataX
               Next
    End Property

VarPtr

Public Function VarPtr(ByVal e As Object) As Object
        Dim GC As GCHandle = GCHandle.Alloc(e, GCHandleType.Pinned)
        Dim GC2 As Integer = GC.AddrOfPinnedObject.ToInt32
        GC.Free()
        Return GC2
    End Function