July 22, 2024


A group at UCLA is studying how to deter DVD copying by putting RFID chips on DVDs, according to a story in RFID Journal by Mary Catherine O’Connor. (Noted by Rik Lambers at CoCo.) The article doesn’t say much about what they are planning. Reading between the lines, it looks like the group hasn’t reached the really interesting technical challenges yet.

Putting RFID on DVDs could be a terrible idea if done the wrong way. But if done correctly, it just might make sense.

One bad approach is to store part of the decryption key (needed to decrypt the data on the DVD) on an RFID chip that is attached to the DVD. The DVD player would read this partial key from the RFID and use it, along with the DVD player’s secret key, to decrypt the content. Doing this doesn’t make the content much harder to copy. And it creates several new problems: the new DVDs wouldn’t play in existing players, and the RFID might expose customers to tracking if they carry RFID-DVDs around with them.

A better approach is to use RFID to put a unique “bonus code” on each individual DVD disc. Then you can provide online “bonus features” to users who present a valid bonus code that isn’t being used elsewhere at the same time. If the bonus features are good enough, users will value getting a bonus code and so will be willing to pay more for genuine discs. And the discs will work in existing DVD players, albeit without the bonus features.

Of course, bonus codes can be copied, just like content. But if bonus codes are used to get live access to a website, and that website checks to avoid duplicate use of bonus codes, then widely copied bonus codes will be less useful, and users will have an incentive to protect their bonus codes from copying.

You don’t need RFID to bundle bonus codes with DVDs. Instead, you could put the bonus code onto the DVD with the content, but this may raise manufacturing costs, by requiring each DVD to contain some unique data, rather than being stamped out in large, identical batches. Or you could print the bonus code onto a sticker and attach the sticker to the DVD case or to the DVD itself. That’s low-tech and effective, but it requires the user to manually enter the bonus code, which is a hassle. RFID allows the DVD player to read the bonus code directly.

If you wanted, you could put the bonus code on both a sticker and an RFID. The DVD player would read the RFID if it could; otherwise the user could enter information from the sticker. Users who worried about privacy could tear off the RFID and just use the sticker. Computer-based DVD players could remember the bonus codes, so the user didn’t need the RFID or sticker anymore.

There are still privacy problems, but these could be addressed if you had a more advanced RFID chip that could execute the right cryptographic protocol. Then the chip could authenticate itself to the bonus features website, in a way that didn’t allow any individual RFID chip to be tracked from moment to moment.

This may be overkill. It’s a lot of technology to get you a relatively small benefit, compared to alternatives like using stickers, or using a disc manufacturing process that can put a small amount of unique data on each disc. But the idea of using RFID with DVDs isn’t totally crazy.


  1. Wouldn’t this just make the “bonus codes” more valuable, and thus the target of increased scrutiny by “pirates”?

  2. PrivacyWatch says

    Ahh…now the real story has come out. They want to use RFIDs be cause they are *programable* so that a DVD can be tied to your biometric data!!


    The article even quotes this sites venerable host.

    This kind of security would be appropriate for nuclear secrets but is completely ridiculous for movies.

  3. PrivacyWatch says

    The idea of using an RFID tag to enable “bonus features,” is a pointless exercise. The industry is looking at RFID as way to enable an additional layer of DRM on the movie on the DVD, not a way of encrypting special features. There would be no benefit to DRMing the bonus material but not the main feature.

  4. I think it is a safe assumption that RFID on DVD will not be used on current DVD format. There is no advantage for the consumer to buy a new DVD player that is harder to use than the old one and offers no additional benefits.

  5. While I usually watch some bonus content on a DVD, I remember one in particular in which I had to install some additional software to see their bonus features. I presume that they simply wanted to use a higher compression encoding than was available on DVD.

    I was unwilling to install their software just to watch the bonus features. Who knew what it did? It could be a totally innocous video player, but it may have had spyware or adware features. (Granted, comming from a large Hollywood studio, it was unlikely to be blatantly so. But it may have called home or served up advertisements that I didn’t want… who can say?) If they really wanted higher compression, they could have offered the videos in a standard format. Regardless, these bonus features are useless to someone with a normal DVD player, or even to someone using a non-MS operating system.

    My point of all this is that it was really annoying. It would’ve been nice to see the bonus features, but I wasn’t about to risk my computer or my privacy to do so.

  6. Is the purpose of the RFID to have a convenient speed bump? Obviously, smart/persistant folks will be able to make copies of even the bonus material and then make it available through various other channels.

    btw, I think dashlog format is a step backwards: the RSS feed that I read in bloglines.com doesn’t provide the direct link; I have to come to the dashlog and then click a second time to get the story.

  7. Funny–didn’t we have a big fight about DVD copy protection once already? I posted about this, citing this post and a couple of others, here:


  8. Stephen Cochran says

    It seems to me that the pervasive theme in the entertainment industry is a challenge of ownership. They want everything to be a rental, usurping the consumer’s control of their property. I know it sounds like hyperbole, but it seems that they won’t be happy until they can control every aspect and level of use.

    This type of restriction just begs to be ignored and circumvented. I don’t care what kind of label you put on a product, if you try to tell Joe Sixpack that he doesn’t own that DVD/CD/Book/whatever, and he can’t do what he wants with it, then Joe Sixpack isn’t going to rise up and march, he’s just going to ignore the restrictions.

  9. According to the article this looks like DIVX version 2:

    “In order to authenticate, the player would also need to link to some type of online network, similar to the EPCglobal Network, that would associate the DVD with a legal sale. Through this system, the copyright owners (the film production company and any other license-holders of the content) would have digital rights management over the work.”

    In this case, the RFID is only added as a way of providing a unique identifier to a stamped DVD. I don’t want to have to authenticate my DVDs online to play it. I also don’t want movie studios to have a database of DVDs that I have watched or rented and I don’t want the studios to make an end run around the Doctrine of First Sale that allows video stores to rent DVDs without paying royalties. By using an authentication system, the studios could limit the number of players a DVD is authorized to play on, or even the number of times you are allowed to play a DVD. This worse that the RFID privacy concerns.