February 20, 2018

Study Shows DMCA Takedowns Based on Inconclusive Evidence

A new study by Michael Piatek, Yoshi Kohno and Arvind Krishnamurthy at the University of Washington shows that copyright owners’ representatives sometimes send DMCA takedown notices where there is no infringement – and even to printers and other devices that don’t download any music or movies. The authors of the study received more than 400 spurious takedown notices.

Technical details are summarized in the study’s FAQ:

Downloading a file from BitTorrent is a two step process. First, a new user contacts a central coordinator [a “tracker” – Ed] that maintains a list of all other users currently downloading a file and obtains a list of other downloaders. Next, the new user contacts those peers, requesting file data and sharing it with others. Actual downloading and/or sharing of copyrighted material occurs only during the second step, but our experiments show that some monitoring techniques rely only on the reports of the central coordinator to determine whether or not a user is infringing. In these cases whether or not a peer is actually participating is not verified directly. In our paper, we describe techniques that exploit this lack of direct verification, allowing us to frame arbitrary Internet users.

The existence of erroneous takedowns is not news – anybody who has seen the current system operating knows that some notices are just wrong, for example referring to unused IP addresses. Somewhat more interesting is the result that it is pretty easy to “frame” somebody so they get takedown notices despite doing nothing wrong. Given this, it would be a mistake to infer a pattern of infringement based solely on the existence of takedown notices. More evidence should be required before imposing punishment.

Now it’s not entirely crazy to send some kind of soft “warning” to a user based on the kind of evidence described in the Washington paper. Most of the people who received such warnings would probably be infringers, and if it’s nothing more than a warning (“Hey, it looks like you might be infringing. Don’t infringe.”) it could be effective, especially if the recipients know that with a bit more work the copyright owner could gather stronger evidence. Such a system could make sense, as long as everybody understood that warnings were not evidence of infringement.

So are copyright owners overstepping the law when they send takedown notices based on inconclusive evidence? Only a lawyer can say for sure. I’ve read the statute and it’s not clear to me. Readers who have an informed opinion on this question are encouraged to speak up in the comments.

Whether or not copyright owners can send warnings based on inconclusive evidence, the notification letters they actually send imply that there is strong evidence of infringement. Here’s an excerpt from a letter sent to the University of Washington about one of the (non-infringing) study computers:

XXX, Inc. swears under penalty of perjury that YYY Corporation has authorized XXX to act as its non-exclusive agent for copyright infringement notification. XXX’s search of the protocol listed below has detected infringements of YYY’s copyright interests on your IP addresses as detailed in the attached report.

XXX has reasonable good faith belief that use of the material in the manner complained of in the attached report is not authorized by YYY, its agents, or the law. The information provided herein is accurate to the best of our knowledge. Therefore, this letter is an official notification to effect removal of the detected infringement listed in the attached report. The attached documentation specifies the exact location of the infringement.

The statement that the search “has detected infringements … on your IP addresses” is not accurate, and the later reference to “the detected infringement” also misleads. The letter contains details of the purported infringement, which once again give the false impression that the letter’s sender has verified that infringement was actually occurring:

Evidentiary Information:
Notice ID: xx-xxxxxxxx
Recent Infringement Timestamp: 5 May 2008 20:54:30 GMT
Infringed Work: Iron Man
Infringing FileName: Iron Man TS Kvcd(A Karmadrome Release)KVCD by DangerDee
Infringing FileSize: 834197878
Protocol: BitTorrent
Infringing URL: http://tmts.org.uk/xbtit/announce.php
Infringers IP Address: xx.xx.xxx.xxx
Infringer’s DNS Name: d-xx-xx-xxx-xxx.dhcp4.washington.edu
Infringer’s User Name:
Initial Infringement Timestamp: 4 May 2008 20:22:51 GMT

The obvious question at this point is why the copyright owners don’t do the extra work to verify that the target of the letter is actually transferring copyrighted content. There are several possibilities. Perhaps BitTorrent clients can recognize and shun the detector computers. Perhaps they don’t want to participate in an act of infringement by sending or receiving copyrighted material (which would be necessary to know that something on the targeted computer is willing to transfer it). Perhaps it simply serves their interests better to send lots of weak accusations, rather than fewer stronger ones. Whatever the reason, until copyright owners change their practices, DMCA notices should not be considered strong evidence of infringement.

Comcast's Disappointing Defense

Last week, Comcast offered a defense in the FCC proceeding challenging the technical limitations it had placed on BitTorrent traffic in its network. (Back in October, I wrote twice about Comcast’s actions.)

The key battle line is whether Comcast is just managing its network reasonably in the face of routine network congestion, as it claims, or whether it is singling out certain kinds of traffic for unnecessary discrimination, as its critics claim. The FCC process has generated lots of verbiage, which I can’t hope to discuss, or even summarize, in this post.

I do want to call out one aspect of Comcast’s filing: the flimsiness of its technical argument.

Here’s one example (p. 14-15).

As Congresswoman Mary Bono Mack recently explained:

The service providers are watching more and more of their network monopolized by P2P bandwidth hogs who command a disproportionate amount of their network resources. . . . You might be asking yourself, why don’t the broadband service providers invest more into their networks and add more capacity? For the record, broadband service providers are investing in their networks, but simply adding more bandwidth does not solve [the P2P problem]. The reason for this is P2P applications are designed to consume as much bandwidth as is available, thus more capacity only results in more consumption.

(emphasis in original). The flaws in this argument start with the fact that the italicized segment is wrong. P2P protocols don’t aim to use more bandwidth rather than less. They’re not sparing with bandwidth, but they don’t use it for no reason, and there does come a point where they don’t want any more.

But even leaving aside the merits of the argument, what’s most remarkable here is that Comcast’s technical description of BitTorrent cites as evidence not a textbook, nor a standards document, nor a paper from the research literature, nor a paper by the designer of BitTorrent, nor a document from the BitTorrent company, nor the statement of any expert, but a speech by a member of Congress. Congressmembers know many things, but they’re not exactly the first group you would turn to for information about how network protocols work.

This is not the only odd source that Comcast cites. Later (p. 28) they claim that the forged TCP Reset packets that they send shouldn’t be called “forged”. For this proposition they cite some guy named George Ou who blogs at ZDNet. They give no reason why we should believe Mr. Ou on this point. My point isn’t to attack Mr. Ou, who for all I know might actually have some relevant expertise. My point is that if this is the most authoritative citation Comcast can find, then their argument doesn’t look very solid. (And, indeed, it seems pretty uncontroversial to call these particular packets “forged”, given that they mislead the recipient about (1) which IP address sent the packet, and (2) why the packet was sent.)

Comcast is a big company with plenty of resources. It’s a bit depressing that they would file arguments like this with the FCC, an agency smart enough to tell the difference. Is this really the standard of technical argumentation in FCC proceedings?

Could Use-Based Broadband Pricing Help the Net Neutrality Debate?

Yesterday, thanks to a leaked memo, it came to light that Time Warner Cable intends to try out use-based broadband pricing on a few of its customers. It looks like the plan is for several tiers of use, with the heaviest users possibly paying overage charges on a per-byte basis. In confirming its plans to Reuters, Time Warner pointed out that its heaviest-using five percent of customers generate the majority of data traffic on the network, but still pay as though they were typical users. Under the new proposal, pricing would be based on the total amount of data transferred, rather than the peak throughput on a connection.

If the current, flattened pricing is based on what the connection is worth to a typical customer, who makes only limited use of the connection, then the heaviest five percent of users (let’s call them super-users as shorthand) are reaping a surplus. Bandwidth use might be highly elastic with respect to price, but I think it is also true that the super users do reap a great deal more benefit from their broadband connections than other users do – think of those who pioneer video consumption online, for example.

What happens when network operators fail to see this surplus? They have marginally less incentive to build out the network and drive down the unit cost of data transfer. If the pricing model changed so that network providers’ revenue remained the same in total but was based directly on how much the network is used, then the price would go down for the lightest users and up for the heaviest. If a tiered structure left prices the same for most users and raised them on the heaviest, operators’ total revenue would go up. In either case, networks would have an incentive to encourage innovative, high-bandwidth uses of their networks – regardless of what kind of use that is.

Gigi Sohn of Public Knowledge has come out in favor of Time Warner’s move on these and other grounds. It’s important to acknowledge that network operators still have familiar, monopolistic reasons to intervene against traffic that competes with phone service or cable. But under the current pricing structure, they’ve had a relatively strong argument to discriminate in favor of the traffic they can monetize, and against the traffic they can’t. By allowing them to monetize all traffic, a shift to use based pricing would weaken one of the most persuasive reasons network operators have to oppose net neutrality.