Private Function StringToHex(strText As String) As String
  Dim intIndex As Integer
  On Error GoTo err_exit

  For intIndex = 1 To Len(strText)
    StringToHex = StringToHex & _
          Hex(Asc(Mid$(strText, intIndex, 1)))
  Next
  Exit Function

err_exit:
    StringToHex = ""
End Function

Private Function HexToString(ByVal strText As String) As String
  On Error GoTo err_exit
  Dim intIndex As Integer

  For intIndex = 1 To Len(strText) Step 2
    HexToString = _
        HexToString & Chr$(CLng("&H" & Mid$(strText, intIndex, 2)))
  Next
  Exit Function

err_exit:
  HexToString = ""
End Function