DVD Demystified

DVD on Computers
487
A Recipe for Resistance The DVD Copy Protection Technical Working
Group worked hard to make the licensing process as simple and unrestrictive
as possible, but anything with this many rules and requirements
can easily go awry. Strenuous objections on the part of computer hardware
and software companies had to be overcome, but the golden glow of Hollywood
movies on computers was a strong incentive to compromise.
Most of the computer industry had no say in these negotiations. This is
an industry notorious for its lack of regard for regulations and artificial barriers.
Computer software developers long ago gave up the fight for copy-protected
software because it did little to slow down those determined to make
copies. However, it sorely inconvenienced honest users who were unable to
make legal backup copies or had problems simply installing or uninstalling
the software they had purchased. Microsoft, for instance, loses billions of
dollars to illegal software copying, yet it still makes plenty of money. The
company educates users, employs sophisticated anti-counterfeiting techniques
such as holograms and thermographic ink, and aggressively pursues
counterfeiters and commercial pirates, but it does not usually encrypt its
software applications or use other technical protection methods. Hollywood,
however, is not this sanguine about its bread-and-butter assets.
A worse problem is the potentially onerous restrictions on computer
retailers and computer owners. Many mom and pop computer stores assemble
low-cost systems from diverse components. How happy will they be with
the licensing requirements demanded of them? How many of them will simply
turn to the inevitable gray market for supplies? And what about the
computer owner who simply wants to upgrade to a new video card? Even a
lowly computer owner who purchases a system assembled from licensed
components by a licensed integrator is presumably barred from buying a
new licensed component because these components can only be sold to
licensed integrators. Of course, nothing can prevent end users from swapping
in different video boards without APS and making copies to their
hearts’ content. Clearly, however, the same factors of cost and convenience
that keep consumers from engaging in mass duplication of audio CDs and
videotapes apply to DVD as well, with or without complex technical copy
protection schemes.
The CSS algorithm and keys were supposed to be a big secret, but the
algorithm was reverse engineered and all the keys were derived by computer
hackers. Security experts who analyzed the CSS implementation
noted that its 40-bit key length made it easily compromised through brute
force attacks, especially because only 25 bits of the key were uniquely
employed. Still, CSS prevents the average user from using a computer to
copy a DVD movie, which is what it was intended to do.