Technology in terms you understand. Sign up for the Confident Computing newsletter for weekly solutions to make your life easier. Click here and get The Ask Leo! Guide to Staying Safe on the Internet — FREE Edition as my thank you for subscribing!

Could Copy Protection be Doomed?

The real question is: how long will vendors keep trying to use it?

Become a Patron of Ask Leo! and go ad-free!

This is Leo Notenboom for

This week the tech and geekier news outlets were all abuzz about a number, and how that number was being posted in literally thousands of places around the internet in defiance of those wanting to keep that number secret.

By the end of the week that number was appearing on stickers, in photos, in music (mp3) and has even become someone’s tattoo.

So what’s so special about this number?

It’s the decryption key for all high definition DVDs produced to date.

It’s not a copyright issue (or if it is, that’s beside the point), but the AACS, who own and control the DVD copy-protection scheme is apparently sending out DMCA take-down notices as fast as they can print them. (AACS stands for Advanced Access Content Systems, and DMCA is the Digital Millennium Copyright Act which attempts to codify the relationship of copyright to easily copied digital media.) Even though this isn’t a copyright issue per se, the  DMCA also covers issues such as possession of technology which could be employed to break the encryption used by copyright holders.

In other words being in possession of this number could be a crime.

To grossly oversimplify since the actual methods are incredibly complex, the technical issue is simply this: using public key encryption, the private “secret” key that’s required to unlock the encrypted digital information must be kept in every device capable of using that media. So your HD-DVD player has the key. It’s well hidden, but it’s there.

If your computer can play HD-DVD, that key is there too. Hidden in the software, but it’s there.

And the number? It’s that key. It’s a 128bit number that, with the right software, can be used to decode HD-DVDs and render the copy protection scheme pointless.

Yes, the key’s already been changed, but given that this key was found I  don’t doubt that the next key will be too. And the key after that. And after

Given the incredibly complex software and infrastructure that needed to be created to support this scheme, and that it’s really only going to keep honest people honest since hackers will naturally step up to the challenge and crack it, and make those cracks available to the less-than-honest anyway…

Someone remind me … why are we doing this again?

I’d love to hear what you think. Visit and enter 11463 in the go to article number box to access the show notes and to leave me a comment. While you’re there, browse over 1,100 technical questions and answers on the site.

Till next time, I’m Leo Notenboom, for

Do this

Subscribe to Confident Computing! Less frustration and more confidence, solutions, answers, and tips in your inbox every week.

I'll see you there!

6 comments on “Could Copy Protection be Doomed?”

  1. Reminds me of the old floppy days when the manufacturers would use a laser to permanently damage the disk as a “signature.” The software would look for this “signature” when starting – if the damaged area was missing (i.e., the software had been copied to an error free disk) the software would not run. It took no time for programs like CopyWrite to be created to circumvent these schemes. Some companies required that “master” floppies be locked up – so they used CopyWrite to create back-up floppies that would run on the user’s machine. Cost, circumvention, and user outrage eventually eliminated the laser burned floppies from existence.

  2. So, the key has been changed. What does that mean to everyone who already owns an HD-DVD player? Does it mean they can only play “old” HD-DVD movies, or that they’ll need to be brought in to get (and pay for?) an “upgrade” to the new key? (Actually, they’ll need both keys. And then all three keys once the second is broken. And then all four. And so on.)

    Hash: SHA1

    It’s unclear, but recall that I said the mechanism was extremely complex. :-) I
    believe there’s a way for most players to continue playing new DVDs. Just how they
    pull that off, I’m not sure.
    Version: GnuPG v1.4.6 (MingW32)


  4. I think that everything will be how it always has. Copy protection devices and security measures will fail as hackers and reverse engineers will always be able to figure it out. That’s just the way it is. No software, no DVD, CD, or any media that you are trying to protect would be safe. This has gone on for YEARS and will also go on. Its a battle where no one can win. There will always be people trying to come up with a copy protection that CANT be broken, and there will always be people who HAVE/CAN break it. Thats what I think about this subject.

  5. Copy protection is a waste of time and effort. At some point, all digital media has to be converted to an analogue form in order to view / listen to it, and at that point it can be re-recorded; OK, so there is some loss of quality, but I guess most people who are prepared to buy pirated media will accept that as a trade off against the low price they pay. The media companies need to cut their prices drastically so that piracy ceases to be economically viable – it’s as simple as that.


Leave a reply:

Before commenting please:

  • Read the article.
  • Comment on the article.
  • No personal information.
  • No spam.

Comments violating those rules will be removed. Comments that don't add value will be removed, including off-topic or content-free comments, or comments that look even a little bit like spam. All comments containing links and certain keywords will be moderated before publication.

I want comments to be valuable for everyone, including those who come later and take the time to read.