->"advanced challenge"-crackme vol.1<-

Hi cracker,
this crackme is a little bit harder
than my last ones but I think it could be managed.
The goal:
Calculate a valid reg.code.
It will be nice if you write some notes about 
the way you solved it.
Your tutorial will be published at:
http://crackmes.cjb.net (the official cm-site)

Have fun with it!

Test-value:
---
Terminal Cilla
680bk
---

Thanks for tryin' my crackmes...
(c)Terminal Cilla
   mail: bombasticx@gmx.net
   web : http://crackmez.cjb.net