Dim StringToEncode As String
  Dim sText As String
  Dim I As Integer
  Dim lPos As Long
  ReDim sCode(2) As String
  ReDim sChar(2) As String
 
  sCode(0) = "asdf": sChar(0) = "a"
  sCode(1) = "uiz": sChar(1) = "b"
  sCode(2) = "rfv": sChar(2) = "c"
 
  StringToEncode = "asdfpiojkuizbdslrfvjkdf"
 
  For I = 0 To UBound(sCode)
    StringToEncode = Replace(StringToEncode, _
      sCode(I), "_" & sChar(I))
  Next I
 
  sText = "": lPos = 0
  Do
    lPos = InStr(lPos + 1, StringToEncode, "_")
    If lPos > 0 Then
      sText = sText & Mid$(StringToEncode, lPos + 1, 1)
      lPos = lPos + 2
    End If
  Loop Until lPos = 0
 
   MsgBox sText