Dim i&, Schluessel$, Txt1$, NewChar$(255)
 
'               ABCDEFGHIJKLMNOPQRSTUVWXYZ
  Schluessel = "HNUAGMKDZOBXEJFCSTPVYILWQR"
  For i = 0 To 255
    NewChar(i) = Chr$(i)
  Next i
  For i = 1 To Len(Schluessel)
    NewChar(Asc("A") + i - 1) = Mid$(Schluessel, i, 1)
  Next i
  Txt1 = RichTextBox2.Text
  For i = 1 To Len(Txt1)
    Mid$(Txt1, i, 1) = NewChar(Asc(Mid$(Txt1, i, 1)))
  Next i
  RichTextBox2.Text = Txt1

Gruss,

Zardoz