July 11, 2014

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White House Statement on Cell Phone Unlocking: A First Step Toward DMCA Reform?

Yesterday, the White House officially responded to the online petition to “Make Unlocking Cell Phones Legal,” which garnered more than 100,000 signatures in under 30 days. The Administration’s headline was emphatic: “It’s Time to Legalize Cell Phone Unlocking.” The tech press heralded this significant but symbolic first step in addressing some of the most egregious shortcomings of the Digital Millennium Copyright Act (DMCA). I hope the White House’s response signals a new chapter in the struggle to regain the freedom to innovate, research, create, and tinker. Last week, I discussed the petition and its context with Derek Khanna, who has been a champion of the cause. You can watch the video here:

As Derek pointed out, this battle is connected to a much larger policy problem: the DMCA bans many practices that are good for society–and without clear counterbalancing benefits. Reading the White House statement, it is hard to tell whether the Administration appreciates this fact.
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Is Spotify the Celestial Jukebox for Music?

In 1994, law professor Paul Goldstein popularized the term “celestial jukebox” to refer to his vision of a networked database of consumable on-demand media. In the face of copyright law that was ill-suited to the rapid rate of technological change, he described a system in which consumers would pay-per-play rather than purchasing and owning individual works. In his book Copyright’s Highway, he predicted that, “the pace of technological development is so fast and the forces of market demand so strong that the celestial jukebox, however configured, will be in place sometime early in the twenty-first century.”

The explosion of broadband and mobile internet access has made that viable, and countless startups have taken a stab at implementing the vision. One of the biggest challenges for these companies has been compiling a library of licensed works that is comprehensive enough to attract a critical mass of users. In the music market, the pay-per-play model has generally given way to monthly subscription or ad-based models. I’ve been a casual user of Last.fm and Pandora, but my listening habits haven’t been fundamentally altered. That changed last week when I finally decided to try Spotify. Spotify may be the first real contender for a mainstream “celestial jukebox” of music. But is that a good thing?

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Who Killed the Open Set-Top-Box?

A few years ago, I lived in Cambridge, Massachusetts. With my trusty Hauppauge WinTV-PVR-150 I enjoyed the ability to watch and record Comcast TV on my desktop computer — and even to occasionally edit and re-upload it to YouTube along with fair use critical commentary. When I moved across the river to Boston, Comcast required me to pay for a set-top box that would tune channels on my television. However, when I plugged my PVR-150 into the cable connection, it got almost no channels at all. As it turns out, the Comcast system in Boston had been migrated to use mostly digital signals, but my tuner card worked only with analog cable signals. Fair enough, I thought, I’ll buy a digital cable tuner. As it turned out, that wouldn’t help much. The cable companies had implemented encryption to fight “service theft” of most channels that subscribers had not paid for. As a result, I lost the ability to view channels I had paid for on a device of my choosing.
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Understanding the HDCP Master Key Leak

On Monday, somebody posted online an array of numbers which purports to be the secret master key used by HDCP, a video encryption standard used in consumer electronics devices such as DVD players and TVs. I don’t know if the key is genuine, but let’s assume for the sake of discussion that it is. What does the leak imply for HDCP’s security? And what does the leak mean for the industry, and for consumers?

HDCP is used to protect high-def digital video signals “on the wire,” for example on the cable connecting your DVD player to your TV. HDCP is supposed to do two things: it encrypts the content so that it can’t be captured off the wire, and it allows each endpoint to verify that the other endpoint is an HDCP-licensed device. From a security standpoint, the key step in HDCP is the initial handshake, which establishes a shared secret key that will be used to encrypt communications between the two devices, and at the same time allows each device to verify that the other one is licensed.

As usual when crypto is involved, the starting point for understanding the system’s design is to think about the secret keys: how many there are, who knows them, and how they are used. HDCP has a single master key, which is supposed to be known only by the central HDCP authority. Each device has a public key, which isn’t a secret, and a private key, which only that device is supposed to know. There is a special key generation algorithm (“keygen” for short) that is used to generate private keys. Keygen uses the secret master key and a public key, to generate the unique private key that corresponds to that public key. Because keygen uses the secret master key, only the central authority can do keygen.

Each HDCP device (e.g., a DVD player) has baked into it a public key and the corresponding private key. To get those keys, the device’s manufacturer needs the help of the central authority, because only the central authority can do keygen to determine the device’s private key.

Now suppose that two devices, which we’ll call A and B, want to do a handshake. A sends its public key to B, and vice versa. Then each party combines its own private key with the other party’s public key, to get a shared secret key. This shared key is supposed to be secret—i.e., known only to A and B—because making the shared key requires having either A’s private key or B’s private key.

Note that A and B actually did different computations to get the shared secret. A combined A’s private key with B’s public key, while B combined B’s private key with A’s public key. If A and B did different computations, how do we know they ended up with the same value? The short answer is: because of the special mathematical properties of keygen. And the security of the scheme depends on this: if you have a private key that was made using keygen, then the HDCP handshake will “work” for you, in the sense that you’ll end up getting the same shared key as the party on the other end. But if you tried to use a random “private key” that you cooked up on your own, then the handshake won’t work: you’ll end up with a different shared key than the other device, so you won’t be able to talk to that device.

Now we can understand the implications of the master key leaking. Anyone who knows the master key can do keygen, so the leak allows everyone to do keygen. And this destroys both of the security properties that HDCP is supposed to provide. HDCP encryption is no longer effective because an eavesdropper who sees the initial handshake can use keygen to determine the parties’ private keys, thereby allowing the eavesdropper to determine the encryption key that protects the communication. HDCP no longer guarantees that participating devices are licensed, because a maker of unlicensed devices can use keygen to create mathematically correct public/private key pairs. In short, HDCP is now a dead letter, as far as security is concerned.

(It has been a dead letter, from a theoretical standpoint, for nearly a decade. A 2001 paper by Crosby et al. explained how the master secret could be reconstructed given a modest number of public/private key pairs. What Crosby predicted—a total defeat of HDCP—has now apparently come to pass.)

The impact of HDCP’s failure on consumers will probably be minor. The main practical effect of HDCP has been to create one more way in which your electronics could fail to work properly with your TV. This is unlikely to change. Mainstream electronics makers will probably continue to take HDCP licenses and to use HDCP as they are now. There might be some differences at the margin, where manufacturers feel they can take a few more liberties to make things work for their customers. HDCP has been less a security system than a tool for shaping the consumer electronics market, and that is unlikely to change.

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Will they ever learn? Hollywood still pursuing DRM

In today’s New York Times, we read that Hollywood is working on a grand unified video DRM scheme intended to allow for video portability, such as, for example, when you visit a hotel room, you’d like to have your videos with you.

What’s sad, of course, is that you can have all of this today with very little fuss. I use iTiVo to extract videos from my TiVo, transcoding them to an iPhone-compatible format. I similarly use Fairmount to rip DVDs to my hard drive, making them easy to play later without worrying about the physical media getting damaged or lost. But if I want to download video, I have no easy mechanism to download non-DRM content. BitTorrent gives access to many things, including my favorite Top Gear, which I cannot get through any other channel, but many things I’d like aren’t available, and of course, there’s the whole legality issue.

I recently bought a copy of Disney/Pixar’s Up (Blu-ray), which includes a “Digital Copy” of some sort that’s rippable, but the other ones are rippable as well (even the Bluray), so I haven’t bothered to sort out how the “Digital Copy” works.

(UPDATE: the disc contains Windows and Mac executables which will ask the user for an “activation code” which is then sent to a Disney server which responds with some sort of decryption key. The resulting file is then installed in iTunes or Windows Media Player with their native DRM restrictions. The Disney server, of course, wants you to set up an account, and they’re working up some sort of YouTube-ish streaming experiences for movies where you’ve entered an activation code.)

So what exactly are the Hollywood types cooking up? There are no technical details in the article, but the broad idea seems to be that you authenticate as yourself from any device, anywhere, and then the central server will let you at “your” content. It’s unclear the extent to which they have an offline viewing story, such as you might want to do on your computer on an airplane. One would imagine they would download an encrypted file, perhaps customized for you, along with a dedicated video player that keeps the key material hidden away through easily broken, poorly conceived mechanisms.

It’s not like we haven’t been here before. I just wonder if we’ll have a repeat of the ill-fated SDMI challenge.

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DRM by any other name: The latest from Hollywood

Sunday’s New York Times had an article, Studios’ Quest for Life After DVDs. To nobody’s surprise, consumers want to have convenient access to “their” media, wherever they happen to be, without all the annoying restrictions that come into play when you add DRM to the picture. To many people’s surprise, sales of DVDs (much less Blu-ray) are in trouble.

In the third quarter, studios’ home entertainment divisions generated about $4 billion, down 3.2 percent from a year ago, according to the Digital Entertainment Group, a trade consortium. But digital distribution contributed just $420 million, an increase of 18 percent.

Given that DVDs are really a luxury good (versus, say, food or electricity), the 3.2 percent drop seems like Hollywood is getting off easy. The growth in digital distribution is clearly getting attention, though. What’s going on here? I imagine several things. People sometimes miss their shows. Maybe the cable went out. Maybe the TiVo crashed. Maybe they’re on the road. Drop $2 at the iTunes Store and you’re good to go. That’s attractive and it’s real money.

Still, the article goes on to talk about… yet more DRM.

Standing in the way are technology hurdles — how to let consumers play a video on various devices without letting them share it with 10,000 close friends on a pirate site — and the reluctance of studios to cooperate too closely with rivals for reasons of antitrust scrutiny and sheer competitiveness.

And piracy, at least conceptually, would be less of a worry. The technology [Disney's Keychest] rests on cloud computing, in which huge troves of data are stored on remote servers so users have access from anywhere. Movies would be streamed from the cloud and never downloaded, making them harder to pirate.

Of course, this is baloney. If it’s going to work on my iPhone while I’m sitting in an airplane, the entire video needs to be stored there in advance. Furthermore, if the video is supposed to be “high definition,” that’s a bare minimum of 5 megabits/sec. (Broadcast HD is 20 megabits/sec and Blu-ray is 48 megabits/sec.) Most home DSL or cable modem connections either will never go that fast, or certainly cannot maintain those speeds without hiccups, particularly when sharing the line with other users. To do high quality video, you either have to have a real broadcast medium (cable, over-the-air, or satellite) or you have to download in advance and store on a hard drive.

And, of course, once you’ve stored the video, it’s just not that hard to extract it. And it always will be. The challenge for Hollywood is to change the incentives of the game. Maybe sell me a flat-rate subscription. Maybe bundle it with my DSL provider. But make the experience compelling enough and cheap enough, and I’ll do it. I regularly extract video from my TiVo and copy it to my iPhone via third-party software. It’s practically painless and it happens to yield files that I could share with the world, but I don’t. Why? Because there’s real downside (I’d rather not get sued, thanks), and no particular upside.

So, dearest Hollywood executive, consider that selling your content for a reduced price, with no DRM, is not the same thing as “giving it away.” If you allow third-parties to license your content and distribute it without DRM, you can still go after the “pirates”, yet you’ll allow normal people to enjoy your work without making them suffer for it. Yes, you may have kids copying content from one to the next, just like we used to do dubbing cassette tapes, but those incremental losses can and will be offset by the incremental gains of people enjoying your work and hitting the “buy” button.

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AP's DRM Announcement: Much Ado About Nothing

Last week the Associated Press announced it would be developing some kind of online news registry to control use of news content. From AP’s press release:

The registry will employ a microformat for news developed by AP and which was endorsed two weeks ago by the Media Standards Trust, a London-based nonprofit research and development organization that has called on news organizations to adopt consistent news formats for online content. The microformat will essentially encapsulate AP and member content in an informational “wrapper” that includes a digital permissions framework that lets publishers specify how their content is to be used online and which also supplies the critical information needed to track and monitor its usage.

The registry also will enable content owners and publishers to more effectively manage and control digital use of their content, by providing detailed metrics on content consumption, payment services and enforcement support. It will support a variety of payment models, including pay walls.

It was hard to make sense of this, so I went looking for more information. AP posted a diagram of the system, which only adds to the confusion — your satisfaction with the diagram will be inversely proportional to your knowledge of the technology.

As far as I can tell, the underlying technology is based on hNews, a microformat for news, shown in the AP diagram, that was announced by AP and the Media Standards Trust two weeks before the recent AP announcement.

Unfortunately for AP, the hNews spec bears little resemblance to AP’s claims about it. hNews is a handy way of annotating news stories with information about the author, dateline, and so on. But it doesn’t “encapsulate” anything in a “wrapper”, nor does it do much of anything to facilitate metering, monitoring, or paywalls.

AP also says that hNews ” includes a digital permissions framework that lets publishers specify how their content is to be used online”. This may sound like a restrictive DRM scheme, aimed at clawing back the rights copyright grants to users. But read the fine print. hNews does include a “rights” field that can be attached to an article, but the rights field uses ccREL, the Creative Commons Rights Expression Language, whose definition states unequivocally that it does not limit users’ rights already granted by copyright and can only convey further rights to the user. Here’s the ccREL definition, page 9:

Here are the License properties defined as part of ccREL:

  • cc:permits — permits a particular use of the Work above and beyond what default copyright law allows.
  • cc:prohibits — prohibits a particular use of the Work, specifically affecting the scope of the permissions provided by cc:permits (but not reducing rights granted under copyright).

It seems that there is much less to the AP’s announcement than meets the eye. If there’s a story here, it’s in the mismatch between the modest and reasonable underlying technology, and AP’s grandiose claims for it.

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Lessons from Amazon's 1984 Moment

Amazon got some well-deserved criticism for yanking copies of Orwell’s 1984 from customers’ Kindles last week. Let me spare you the copycat criticism of Amazon — and the obvious 1984-themed jokes — and jump right to the most interesting question: What does this incident teach us?

Human error was clearly part of the problem. Somebody at Amazon decided that repossessing purchased copies of 1984 would be a good idea. They were wrong about this, as both the public reaction and the company’s later backtracking confirm. But the fault lies not just with the decision-maker, but also with the factors that made the decision more likely, including some aspects of the technology itself.

Some put the blame on DRM, but that’s not the problem here. Even if the Kindle used open formats and let you export and back up your books, Amazon could still have made 1984 disappear from your Kindle. Yes, some users might have had backups of 1984 stored elsewhere, but most users would have lost their only copy.

Some blame cloud computing, but that’s not precisely right either. The Kindle isn’t really a cloud device — the primary storage, computing and user interface for your purchased books are provided by your own local Kindle device, not by some server at Amazon. You can disconnect your Kindle from the network forever (by flipping off the wireless network switch on the back), and it will work just fine.

Some blame the fact that Amazon controls everything about the Kindle’s software, which is a better argument but still not quite right. Most PCs are controlled by a single company, in the sense that that company (Microsoft or Apple) can make arbitrary changes to the software on the PC, including (in principle) deleting files or forcibly removing software programs.

The problem, more than anything else, is a lack of transparency. If customers had known that this sort of thing were possible, they would have spoken up against it — but Amazon had not disclosed it and generally does offer clear descriptions of how the product works or what kinds of control the company retains over users’ devices.

Why has Amazon been less transparent than other vendors? I’m not sure, but let me offer two conjectures. It might be because Amazon controls the whole system. Systems that can run third-party software have to be more open, in the sense that they have to tell the third-party developers how the system works, and they face some pressure to avoid gratuitous changes that might conflict with third-party applications. Alternatively, the lack of transparency might be because the Kindle offers less functionality than (say) a PC. Less functionality means fewer security risks, so customers don’t need as much information to protect themselves.

Going forward, Amazon will face more pressure to be transparent about the Kindle technology and the company’s relationship with Kindle buyers. It seems that e-books really are more complicated than dead-tree books.

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DRM In Retreat

Last week’s agreement between Apple and the major record companies to eliminate DRM (copy protection) in iTunes songs marks the effective end of DRM for recorded music. The major online music stores are now all DRM-free, and CDs still lack DRM, so consumers who acquire music will now expect it without DRM. That’s a sensible result, given the incompatibility and other problems caused by DRM, and it’s a good sign that the record companies are ready to retreat from DRM and get on with the job of reinventing themselves for the digital world.

In the movie world, DRM for stored content may also be in trouble. On DVDs, the CSS DRM scheme has long been a dead letter, technologically speaking. The Blu-ray scheme is better, but if Blu-ray doesn’t catch on, this doesn’t matter.

Interestingly, DRM is not retreating as quickly in systems that stream content on demand. This makes sense because the drawbacks of DRM are less salient in a streaming context: there is no need to maintain compatibility with old content; users can be assumed to be online so software can be updated whenever necessary; and users worry less about preserving access when they know they can stream the content again later. I’m not saying that DRM causes no problems with streaming, but I do think the problems are less serious than in a stored-content setting.

In some cases, streaming uses good old fashioned incompatibility in place of DRM. For example, a stream might use a proprietary format and the most convenient software for watching streams might lack a “save this video” button.

It remains to be seen how far DRM will retreat. Will it wither away entirely, or will it hang on in some applications?

Meanwhile, it’s interesting to see traditional DRM supporters back away from it. RIAA chief Mitch Bainwol now says that the RIAA is agnostic on DRM. And DRM cheerleader Bill Rosenblatt has relaunched his “DRM Watch” blog under the new title “Copyright and Technology“. The new blog’s first entry: iTunes going DRM-free.

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Plenty of Blame to Go Around in Yahoo Music Shutdown

People have been heaping blame on Yahoo after it announced plans to shut down its Yahoo Music Store DRM servers on September 30. The practical effect of the shutdown is to make music purchased at the store unusable after a while.

Though savvy customers tended to avoid buying music in forms like this, where a company had to keep some distant servers running to keep the purchased music alive, those customers who did buy – taking reassurances from Yahoo and music industry at face value – are rightly angry. In the face of similar anger, Microsoft backtracked on plans to shutter its DRM servers. It looks like Yahoo will stay the course.

Yahoo deserves blame here, but let’s not forget who else contributed to this mess. Start with the record companies for pushing this kind of DRM, and the DRM agenda generally, despite the ample evidence that it would inconvenience paying customers without stopping infringement.

Even leaving aside past mistakes, copyright owners could step in now to help users, either by enticing Yahoo to keep its servers running, or by helping Yahoo create and distribute software that translates the music into a usable form. If I were a Yahoo Music customer, I would be complaining to the copyright owners now, and asking them to step in and stand behind their product.

Finally, let’s not forget the role of Congress. The knowledge of how to jailbreak Yahoo Music tracks and transform them into a stable, usable form exists and could easily be packaged in software form. But Congress made it illegal to circumvent Yahoo’s DRM, even to enable noninfringing use of a legitimately purchased song. And they made it illegal to distribute certain software tools to enable those uses. If Congress had paid more attention to consumer interests in drafting the Digital Millennium Copyright Act, or if it had passed any of the remedial legislation offered since the DMCA took effect, then the market could solve this Yahoo problem all on its own. If I were a Yahoo Music customer, I would be complaining to Congress now, and asking them to stop blocking consumer-friendly technologies.

And needless to say, I wouldn’t be buying DRM-encumbered songs any more.

UPDATE (July 29, 2008): Yahoo has now done the right thing, offering to give refunds or unencumbered MP3s to the stranded customers. I wonder how much this is costing Yahoo.