What are the requirements on the challenge-response authentication? What kind of standard do you have in mind, or can it be a self-made (and relatively simple) solution? Could you describe the application a bit more in detail?
It is, don't worry. But many of us are wary of the situation described as "teacher gave us homework, sounds difficult and I don't want it - you guys on the internet do it for me now". I don't think that's what we have here.