February 20, 2018

A Freedom-of-Speech-based Approach To Limiting Filesharing – Part II: The Block List

On Wednesday we discussed the open structure of filesharing and its resulting vulnerability to spam. While there are some similarities between e-mail and gnutella spam, the spoof files have no analogue in e-mail. When MediaDefender puts up spoofs for Rihanna’s Disturbia, unless you are using gnutella to search for Disturbia – which you cannot legally do – the spam has no effect on you. But of course, if MediaDefender is allowed to persist in doing this successfully, gnutella would lose much of its appeal.

The solution that has traditionally been adopted is an IP block list. When MediaDefender puts up spoof files, they come from the IP addresses of MediaDefender’s computers. While it is possible that MediaDefender could (and doubtless would have to) get several computers to perform the spoofing, they are all accessing the internet through a single ISP. Therefore, when an ISP is found to be hosting a spoofing operation such as MediaDefender’s, the entire range of IP addresses owned by the ISP is added to filesharing program’s IP block list. When an IP address is on the block list, other computers will refuse to connect to it, thereby preventing it from filesharing.

Because filesharing becomes useless without something to stop spoof files, IP block lists are a common part of P2P sharing programs. Generally, they are posted on web sites and downloaded by the P2P program, at the direction of the user. The program is generally configurable to download the block list from a site of the user’s choosing, and the block list file is stored in a known location and is readable and editable by interested users. For example, this forum discussion describes how to download the block file for the P2P client eMule.

What is not broadly appreciated is the role that LimeWire the corporation plays in the gnutella network. LimeWire is not merely a provider of software (and there are non-LimeWire gnutella clients, not as popular as LimeWire). Limewire’s client software, aside from supporting the gnutella protocol, receives from LimeWire a cryptographically signed file, called simpp.xml. This file contains a number of parameters for the operation of the client, including its IP block list. Because of the strong cryptographic signing by LimeWire corporation, no one else may send the list. LimeWire can therefore, at its sole discretion, block hosts from sending data to essentially all of its clients. Anyone putting up files that LimeWire deems unsuitable is knocked off in a matter of hours, and, since LimeWire is by far the most popular gnutella client, the spoofer is effectively shut down.

The LimeWire P2P clients are unusual in that there is nothing configurable about the choice of block list. Moreover, unlike other programs, there is no way for anyone other than LimeWire to send it, and no way for a non-technical user to examine its contents – in fact, the typical non-technical user would not even know that blocking is going on. (The only way to turn off blocking is on an advanced configuration panel.)

(One other interesting feature is also revealed from looking at the simpp.xml file: LimeWire has added a facility that allows its server, and only its server, to contact a running LimeWire client and ask it various questions about what the client is doing. This feature allows LimeWire to phone up LimeWire clients and inspect them, thereby gathering information about its network. This feature could be used as a sort of mini-spyware, though it is not clear exactly what LimeWire does with it.)

Tomorrow we shall see one way to interpret the legal significance of these behaviors on LimeWire corporation’s part.

A Freedom-of-Speech Approach To Limiting Filesharing – Part I: Filesharing and Spam

[Today we kick off a series of three guest posts by Mitch Golden. Mitch was a professor of physics when, in 1995, he was bitten by the Internet bug and came to New York to become an entrepreneur and consultant. He has worked on a variety of Internet enterprises, including one in the filesharing space. As usual, the opinions expressed in these posts are Mitch’s alone. — Ed]

The battle between the record labels and filesharers has been somewhat out of the news a bit of late, but it rages on still. There is an ongoing court case Arista Records v LimeWire, in which a group of record labels are suing to have LimeWire held accountable for the copyright infringing done by its users. Though this case has attracted less attention than similar cases before it, it may raise interesting issues not addressed in previous cases. Though I am a technologist, not a lawyer, this series of posts will advocate a way of looking at the issues, including legal, using a freedom-of-speech based approach, which leads to some unusual conclusions.

Let’s start by reviewing some salient features of filesharing.

Filesharing is a way for a group of people – who generally do not know one another – to allow one another to see what files they collectively have on their machines, and to exchange desired files with each other. There are at least two components to a filesharing system: one allows a user who is looking for a particular file to see if someone has it, and another that allows the file to be transferred from one machine to the other.

One of the most popular filesharing programs in current use is LimeWire, which uses a protocol called gnutella. Gnutella is decentralized, in the sense that neither the search nor the exchange of files requires any central server. It is possible, therefore, for people to exchange copyrighted files – in violation of the law – without creating any log of the search or exchange in a central repository.

The gnutella protocol was originally created by developers from Nullsoft, the company that had developed the popular music player WinAmp, shortly after it was acquired by AOL. AOL was at that time merging with Time Warner, a huge media company, and so the idea that they would be distributing a filesharing client was quite unamusing to management. Work was immediately discontinued; however, the source for the client and the implementation of the protocol had already been released under the GPL, and so development continued elsewhere. LimeWire made improvements both to the protocol and the interface, and their client became quite popular.

The decentralized structure of filesharing does not serve a technical purpose. In general, centralized searching is simpler, quicker and more efficient, and so, for example, to search the web we use Google or Yahoo, which are gigantic repositories. In filesharing, the decentralized search structure instead serves a legal purpose: to diffuse the responsibility so no particular individual or organization can be held accountable for promoting the illegal copying of copyright materials. At the time the original development was going on, the Napster case was in the news, in which the first successful filesharing service was being sued by the record labels. The outcome of that case a few months later resulted in Napster being shut down, as the US courts held it (which was a centralized search repository) responsible for the copyright infringing file sharing its users were doing.

Whatever their legal or technical advantages, decentralized networks, by virtue of their openness, are vulnerable to a common problem: spam. For example, because anyone may send anyone else an e-mail, we are all subject to a deluge of messages trying to sell us penny stocks and weight loss remedies. Filesharing too is subject this sort of cheating. If someone is looking for, say, Rihanna’s recording Disturbia, and downloads an mp3 file that purports to be such, what’s to stop a spammer from instead serving a file with an audio ad for a Canadian pharmacy?

Spammers on the filesharing networks, however, have more than just the usual commercial motivations in mind. In general, there are four categories of fake files that find their way onto the network.

  • Commercial spam
  • Pornography and Ads for Pornography
  • Viruses and trojans
  • Spoof files

The last of these has no real analogue to anything people receive in e-mail It works as follows: if, for example, Rihanna’s record label wants to prevent you from downloading Disturbia, they might hire a company called MediaDefender. MediaDefender’s business is to put as many spoof files as possible on gnutella that purport to be Disturbia, but instead contain useless noise. If MediaDefender can succeed in flooding the network so that the real Disturbia is needle in a haystack, then the record label has thwarted gnutella’s users from violating their copyright.

Since people are still using filesharing, clearly a workable solution has been found to the problem of spoof files. In tomorrow’s post, I discuss this solution, and in the following post, I suggest its legal ramifications.

The Return of 3-D Movies

[Today’s guest post is by longtime reader and commenter Mitch Golden. Thanks, Mitch! If you’re a Freedom to Tinker reader and have a great idea for a guest post, please let me know. – Ed]

Last Friday I was at a movie preview for a concert movie called U23D, which, as you will correctly surmise, was a U2 concert filmed in digital 3D.

A few weeks ago I saw the new film Beowulf, also in 3D.

As I look out the office window to the AMC Loews on 84th St, I see that the marquee is already pitching Hannah Montana 3d, not due out until February.

And outside that same theater is a 3d movie poster for the upcoming Speed Racer movie.

Suddenly everything is floating in space, after decades of flatness. What gives?

Those of us who frequent Freedom To Tinker know that there are two approaches for producers operating in our world of nearly-zero-cost copying. The option most often pursued thus far by the content industries has been to pin hope on a technological fix – DRM – and then use political muscle to get governments around the world to mandate its use. Thus far this strategy can only be said to have been pretty much a total train wreck for all the parties involved – from the record industry to Microsoft – and it has had the disastrous side effect (from their point of view) of persuading an entire generation – and then some – that the media companies are “the man” and so file sharing is not immoral.

Of course the other option – thus far being resisted strenuously by the record labels – is to try a new business model. Sell the customers something better than what they can get for free. Maybe – just maybe – that’s what’s going on here.

As you doubtless know, there’s nothing new about 3d movie or photos. In fact, they go back nearly to the very beginning of photography. To make the 3d effect work, you just need to present different images, shot from slightly different perspectives, to the two eyes. While various systems have been invented over the years to do this (see the wikipedia page on the subject for a bit of the history of the technology), they all to a greater or lesser extent shared the common faults that (a) the theater had to install special equipment (including a more expensive screen that reflects polarized light without depolarizing it), (b) the film was bigger and more difficult to handle, and (c) splicing the film print when it broke required careful treatment to avoid getting the two eyes out of sync. So it just wasn’t quite worth it.

So why are we seeing these movies again now? One possibility is that the explanation for the renaissance of 3d is just that digital technology solves some of these problems (especially b and c), and so filmmakers are interested in trying again.

However, I think it’s possible there’s something else going on. Could it have something to do with the fact that a 3d movie cannot be pirated?

According to IMDB, the LA premier of Beowulf was on November 5, 2007 and the film was officially released in the US on November 16. On the other hand, according to vcdquality (a news site that announces the “releases” of films into various darknets) it was already available for file sharing by November 15.

Isn’t it just possible that the studios were thinking: Hey guys, I know you could just download this fantasy flick and see it on your widescreen monitor. But unless you give us $11 and sit in a dark theater with the polarized glasses, you won’t be seeing the half-naked Angelina Jolie literally popping off the screen!

Maybe the studios have learned something after all.