Зашифровать имя файла и избежать недопустимых для пути символов

        Dim Fname As String = "aOk/QbzOTsYehu3fN7r81OOM|VrddyZMULCR5iFplz6xCwP80RqjV+sqavjmYOn/Y"
        Fname = Regex.Replace(Fname, "[\|/]", String.Empty)

    Private Sub Button2_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button2.Click
        For Each fn As String In IO.Directory.GetFiles("C:\2")
            My.Computer.FileSystem.RenameFile(fn, NedoRasShifr(IO.Path.GetFileName(fn), "cyberforum"))
        Next
    End Sub
    Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
        For Each fn As String In IO.Directory.GetFiles("C:\2")
            My.Computer.FileSystem.RenameFile(fn, NedoShifr(IO.Path.GetFileName(fn), "cyberforum"))
        Next
    End Sub
    Function NedoShifr(ByVal InputString As String, ByVal Key As String) As String
        Dim Summ As Integer
        Dim K() As Char = Key.ToCharArray
        For Each Kc As Char In K
            Summ += Asc(Kc)
        Next
        Dim Ca() As Char = InputString.ToCharArray
        For I As Integer = 0 To Ca.Length - 1
            Ca(I) = ChrW(Asc(Ca(I)) + Summ + I)
        Next
        Return New String(Ca)
    End Function
    Function NedoRasShifr(ByVal InputString As String, ByVal Key As String) As String
        Dim Summ As Integer
        Dim K() As Char = Key.ToCharArray
        For Each Kc As Char In K
            Summ += Asc(Kc)
        Next
        Dim Ca() As Char = InputString.ToCharArray
        For I As Integer = 0 To Ca.Length - 1
            Ca(I) = Chr((AscW(Ca(I)) - Summ - I))
        Next
        Return New String(Ca)
    End Function