Badinage: The cache copy doesn't mean it's been withdrawn from the site, I just downloaded it right now. The cache was provided as it is in HTML, so users who don't have PDF wouldn't have to bother getting it or go to another site to convert it.
Whatever security features exist, screen capture is always an option.
I couldn't find any information regarding the new PDF technologies, could you give a link to the changes?
Interestingly, a look at my PDF viewer's (xpdf) site on page http://www.foolabs.com/xpdf/cracking.html suggests that a change of the code would allow for evasion of security.
Considering that the code is freely available, it would seem quite weak. But I could be interpreting it totally wrongly.