Q:

How to prevent file duplication/burning of a CD/DVD

I have HTML and SWF files that I want to put on a CD. How can I protect the contents on the CD, or make it difficult for someone to burn or duplicate them?

A:

Fundamentally, you can't. It's impossible.
This is because you are unable to distinguish between an attacker and a legitimate user. You want the legitimate user to be able to access the data, you want the attacker not to be able to, but you can't tell if Alice is a legitimate user or an attacker. 
Despite it being impossible, a lot of people have put a lot of effort and resources into trying to do it anyway. The closest they've come is with two approaches:

Have the users access the data only using computers that you control.
Authenticate each user before giving them access to the data, analyze their usage patterns, and revoke their access if you believe them to be an attacker.

Note that neither of these techniques work (because it's impossible) but they can sometimes delay unsophisticated attackers very briefly. (While unsophisticated attackers can't break these techniques, they can download copies of your data from sophisticated attackers.)

