December 25, 2024

Posts Comments

Archives for 2009

Introducing FedThread: Opening the Federal Register

October 5, 2009 by

Today we are rolling out FedThread, a new way of interacting with the Federal Register. It’s the latest civic technology project from our team at Princeton’s Center for Information Technology Policy.

The Federal Register is “[t]he official daily publication for rules, proposed rules, and notices of Federal agencies and organizations, as well as executive orders and other presidential documents.” It’s published by the U.S. government, five days a week. The Federal Register tells citizens what their government is doing, in a lot more detail than the news media do.

FedThread makes the Federal Register more open and accessible. FedThread gives users:

  • collaborative annotation: Users can attach a note to any paragraph of the Federal Register; a conversation thread hangs off of every paragraph.
  • advanced search: Users can search the Federal Register (going back to 2000) on full text, by date, agency, and other fields.
  • customized feeds: Any search can be turned into an RSS feed. The resulting feed will include any new items that match the search query. Feeds can be delivered by email as well.

I think FedThread is a nice tool, but what’s most amazing to me is that the whole project took only ten days to create. Ten days ago we had no code, no HTML, no plan, not even a block diagram on a whiteboard. Today we launched a pretty good service.

How was this possible? Three things enabled it.

First, government provided the necessary data, for bulk download, in a format (XML) that’s easy for software to handle. This let us acquire and manipulate the underlying data (Federal Register contents) quickly. Folks at the Government Printing Office, National Archives and Records Administration, and Office of Science and Technology Policy all helped to make this possible. The roll-out of the government’s XML-based Federal Register site today is a significant step forward.

Second, we had great tools, such as Linux, Apache, MySql, Python, Django, jQuery, Datejs, and lxml. These tools are capable, flexible, and free, and they fit together in useful ways. More than once we faced a challenging engineering problem, only to find an existing tool that did almost exactly what we needed. When we needed a tool for managing inline discussion threads within a document, Adrian Holovaty, Jacob Kaplan-Moss and Jack Slocum graciously let us use their code from djangobook.com, which served as the basis for our system. Tools like these help small teams build big projects quickly.

Third, we have a amazing team. A project like this needs people who are super-smart, tireless, have great engineering judgment, and know how to work as a team. Joe Calandrino, Ari Feldman, Harlan Yu, and Bill Zeller all did fantastic work building the site. We set an insane schedule — at the start we guessed we had a 50% chance of having anything at all ready by today — and they raced ahead of the schedule, to the point that we expanded the project’s scope more than once. Great job, guys! Now please get some sleep.

We hope FedThread is a useful tool that brings more people into contact with the operations of their government — one small step in a larger trend of using technology to make government more transparent.

Filed Under: Uncategorized Tagged With:

Antisocial networking

October 2, 2009 by

I just got my invitation to Google Wave. The prototype that’s now public doesn’t have all of the amazing features in the original video demos. At this point, it’s pretty much just a way of collecting IM-style conversations all in one place. But several of my friends are already there, and I’ve had a few conversations there already.

How am I supposed to know that there’s something new going on at Wave? Right now, I need to keep a tab open in my browser and check in, every once in a while, to see what’s up. Right now, my standard set of tabs includes my Gmail, calendar, RSS reader, New York Times homepage, Facebook page, and now Google Wave. Add in the occasional Twitter tab (or dedicated Twitter client, if I feel like running it) plus I’ll occasionally have an IM window open. All of these things are competing for my attention when I’m supposed to be getting real work done.

A common way that people try to solve this problem is by building bridges between these services. If you use Twitter and Facebook, there are several ways to arrange for your tweets to show up at Facebook (bewildering Facebook users with all the #hashtags and @references) and there are also a handful of ways for getting data out of Facebook. I’d been using FriendFeed as a central hub for all this, but it would sometimes stop working for days at a time. Now that they’ve been bought out by Facebook, maybe this will shake itself out.

The bigger problem is that these various vendors and technologies have different data models for visibility and for how metadata is represented. In Twitter, everything is default-public, follow-up comments are first-class objects in the system, and there’s effectively no metadata outside of the message, causing Twitter users to have adopted a variety of seemingly obscure conventions (e.g., “RT” to indicate a retweet of some other tweet). Contrast this with Facebook, where comments are a very different sort of message from the parent messages, where they have all sorts of security rules (that nobody really understands) about who can see what, and where there is actually structure to a message. If I link to a Youtube video, it gets magically embedded, versus the annoying URL shorteners that people have to use to shoehorn messages into Twitter.

Comments are a favorite area for people to complain. Twitter comments are often implicit with the @username tags. If I’m following a friend and a friend-of-my-friend comments on one of their tweets, I won’t necessary see it. In Facebook, I have a better shot at seeing those comments. But what if I wrote a blog post here at Freedom to Tinker, which Facebook nicely picks it up and makes it look just like I posted a note on my Facebook page. Now we’ll have comments on Freedom to Tinker and more comments inside Facebook which won’t intermingle. Of course, thanks to FriendFeed, a tweet will (probably) be automatically generated when I post this, causing some small amount of Twitter commenting traffic, and there may be comments within FriendFeed itself as well as Google Reader commentary (which is also different from Google Reader’s “share with note” commentary).

Given these disparate data models, there’s no easy way to unify Twitter and Facebook, much less the commenting disaspora, even assuming you could sort out the security concerns and you could work around Facebook’s tendency to want to restrict the flow of data out of its system. This is all the more frustrating because RSS completely solved the initial problem of distributing new blog posts in the blog universe. I used to keep a bunch of tabs open to various blog-like things that I followed, but that quickly proved unwieldy, whereas an RSS aggregator (Google Reader, for me) solved the problem nicely. Could there ever be a social network/microblogging aggregator?

There are no lack of standards-in-the-wings that would like to do this. (See, for example, OpenMicroBlogging, or our own work on BirdFeeder.) Something like Google Wave could subsume every one of these platforms, although I fear that integrating so many different data models would inevitably result in a deeply clunky UI.

In the end, I think the federation ideas behind Google Wave and BirdFeeder, and good old RSS blog feeds, will ultimately win out, with interoperability between the big vendors, just like they interoperate with email. Getting there, however, isn’t going to happen easily.

Filed Under: Uncategorized Tagged With:

Breaking Vanish: A Story of Security Research in Action

September 29, 2009 by

Today, seven colleagues and I released a new paper, “Defeating Vanish with Low-Cost Sybil Attacks Against Large DHTs“. The paper’s authors are Scott Wolchok (Michigan), Owen Hofmann (Texas), Nadia Heninger (Princeton), me, Alex Halderman (Michigan), Christopher Rossbach (Texas), Brent Waters (Texas), and Emmett Witchel (Texas).

Our paper is the next chapter in an interesting story about the making, breaking, and possible fixing of security systems.

The story started with a system called Vanish, designed by a team at the University of Washington (Roxana Geambasu, Yoshi Kohno, Amit Levy, and Hank Levy). Vanish tries to provide “vanishing data objects” (VDOs) that can be created at any time but will only be usable within a short time window (typically eight hours) after their creation. This is an unusual kind of security guarantee: the VDO can be read by anybody who sees it in the first eight hours, but after that period expires the VDO is supposed to be unrecoverable.

Vanish uses a clever design to do this. It takes your data and encrypts it, using a fresh random encryption key. It then splits the key into shares, so that a quorum of shares (say, seven out of ten shares) is required to reconstruct the key. It takes the shares and stores them at random locations in a giant worldwide system called the Vuze DHT. The Vuze DHT throws away items after eight hours. After that the shares are gone, so the key cannot be reconstructed, so the VDO cannot be decrypted — at least in theory.

What is this Vuze DHT? It’s a worldwide peer-to-peer network, containing a million or so computers, that was set up by Vuze, a company that uses the BitTorrent protocol to distribute (licensed) video content. Vuze needs a giant data store for its own purposes, to help peers find the videos they want, and this data store happens to be open so that Vanish can use it. The million-computer extent of the Vuze data store was important, because it gave the Vanish designers a big haystack in which to hide their needles.

Vanish debuted on July 20 with a splashy New York Times article. Reading the article, Alex Halderman and I realized that some of our past thinking about how to extract information from large distributed data structures might be applied to attack Vanish. Alex’s student Scott Wolchok grabbed the project and started doing experiments to see how much information could be extracted from the Vuze DHT. If we could monitor Vuze and continuously record almost all of its contents, then we could build a Wayback Machine for Vuze that would let us decrypt VDOs that were supposedly expired, thereby defeating Vanish’s security guarantees.

Scott’s experiments progressed rapidly, and by early August we were pretty sure that we were close to demonstrating a break of Vanish. The Vanish authors were due to present their work in a few days, at the Usenix Security conference in Montreal, and we hoped to demonstrate a break by then. The question was whether Scott’s already heroic sleep-deprived experimental odyssey would reach its destination in time.

We didn’t want to ambush the Vanish authors with our break, so we took them aside at the conference and told them about our preliminary results. This led to some interesting technical discussions with the Vanish team about technical details of Vuze and Vanish, and about some alternative designs for Vuze and Vanish that might better resist attacks. We agreed to keep them up to date on any new results, so they could address the issue in their talk.

As it turned out, we didn’t establish a break before the Vanish team’s conference presentation, so they did not have to modify their presentation much, and Scott finally got to catch up on his sleep. Later, we realized that evidence to establish a break had actually been in our experimental logs before the Vanish talk, but we hadn’t been clever enough to spot it at the time. Science is hard.

Some time later, I ran into my ex-student Brent Waters, who is now on the faculty at the University of Texas. I mentioned to Brent that Scott, Alex and I had been studying attacks on Vanish and we thought we were pretty close to making an attack work. Amazingly, Brent and some Texas colleagues (Owen Hoffman, Christopher Rossbach, and Emmett Witchel) had also been studying Vanish and had independently devised attacks that were pretty similar to what Scott, Alex, and I had.

We decided that it made sense to join up with the Texas team, work together on finishing and testing the attacks, and then write a joint paper. Nadia Heninger at Princeton did some valuable modeling to help us understand our experimental results, so we added her to the team.

Today we are releasing our joint paper. It describes our attacks and demonstrates that the attacks do indeed defeat Vanish. We have a working system that can decrypt Vanishing data objects (made with the original version of Vanish) after they are supposedly unrecoverable.

Our paper also discusses what went wrong in the original Vanish design. The people who designed Vanish are smart and experienced, but they obviously made some kind of mistake in their original work that led them to believe that Vanish was secure — a belief that we now know is incorrect. Our paper talks about where we think the Vanish authors went wrong, and what security practitioners can learn from the Vanish experience so far.

Meanwhile, the Vanish authors went back to the drawing board and came up with a bunch of improvements to Vanish and Vuze that make our attacks much more expensive. They wrote their own paper about their experience with Vanish and their new modifications to it.

Where does this leave us?

For now, Vanish should be considered too risky to rely on. The standard for security is not “no currently demonstrated attacks”, it is “strong evidence that the system resists all reasonable attacks”. By updating Vanish to resist our attacks, the Vanish authors showed that their system is not a dead letter. But in my view they are still some distance from showing that Vanish is secure . Given the complexity of underlying technologies such as Vuze, I wouldn’t be surprised if more attacks turn out to be possible. The latest version of Vanish might turn out to be sound, or to be unsound, or the whole approach might turn out to be flawed. It’s too early to tell.

Vanish is an interesting approach to a real problem. Whether this approach will turn out to work is still an open question. It’s good to explore this question — and I’m glad that the Vanish authors and others are doing so. At this point, Vanish is of real scientific interest, but I wouldn’t rely on it to secure my data.

[Update (Sept. 30, 2009): I rewrote the paragraphs describing our discussions with the Vanish team at the conference. The original version may have given the wrong impression about our intentions.]

Filed Under: Uncategorized Tagged With: , ,

Android Open Source Model Has a Short Circuit

September 26, 2009 by

[Update: Google subsequently worked out a mechanism that allows Cyanogen and others to distribute their mods separate from the Google Apps.]

Last year, Google entered the mobile phone market with a Linux-based mobile operating system. The company brought together device manufacturers and carriers in the Open Handset Alliance, explaining that, “Together we have developed Android™, the first complete, open, and free mobile platform.” There has been considerable engagement from the open source developer community, as well as significant uptake from consumers. Android may have even been instrumental in motivating competing open platforms like LiMo. In addition to the underlying open source operating system, Google chose to package essential (but proprietary) applications with Android-based handsets. These applications include most of the things that make the handsets useful (including basic functions to sync with the data network). This two-tier system of rights has created a minor controversy.

A group of smart open source developers created a modified version of the Android+Apps package, called Cyanogen. It incorporated many useful and performance-enhancing updates to the Android OS, and included unchanged versions of the proprietary Apps. If Cyanogen hadn’t included the Apps, the package would have been essentially useless, given that Google doesn’t appear to provide a means to install the Apps on a device that has only a basic OS. As Cyanogen gained popularity, Google decided that it could no longer watch the project distribute their copyright-protected works. The lawyers at Google decided that they needed to send a Cease & Desist letter to the Cyanogen developer, which caused him to take the files off of his site and spurred backlash from the developer community.

Android represents a careful balance on the part of Google, in which the company seeks to foster open platforms but maintain control over its proprietary (but free) services. Google has stated as much, in response to the current debate. Android is an exciting alternative to the largely closed-source model that has dominated the mobile market to date. Google closely integrated their Apps with the operating system in a way that makes for a tremendously useful platform, but in doing so hampered the ability of third-party developers to fully contribute to the system. Perhaps the problem is simply that they did not choose the right location to draw the line between open vs. closed source — or free-to-distribute vs. not.

The latter distinction might offer a way out of the conundrum. Google could certainly grant blanket rights to third-parties to redistribute unchanged versions of their Apps. This might compromise their ability to make certain business arrangements with carriers or handset providers in which they package the software for a fee. That may or may not be worth it from their business perspective, but they could have trouble making the claim that Android is a “complete, open, and free mobile platform” if they don’t find a way to make it work for developers.

This all takes place in the context of a larger debate over the extent to which mobile platforms should be open — voluntarily or via regulatory mandate. Google and Apple have been arguing via letters to the FCC about whether or not Apple should allow the Google Voice application in the iPhone App Store. However, it is yet to be determined whether the Commission has the jurisdiction and political will to do anything about the issue. There is a fascinating sideshow in that particular dispute, in which AT&T has made the very novel claim that Google Voice violates network neutrality (well, either that or common carriage — they’ll take whichever argument they can win). Google has replied. This is a topic for another day, but suffice to say the clear regulatory distinctions between telephone networks, broadband, and devices have become muddied.

(Cross-posted to Managing Miracles)

Filed Under: Broadband Tagged With: , ,

The Markey Net Neutrality Bill: Least Restrictive Network Management?

September 25, 2009 by

It’s an exciting time in the net neutrality debate. FCC Chairman Jules Genachowski’s speech on Monday promised a new FCC proceeding that will aim to create a formal rule to replace the Commission’s existing policy statement.

Meanwhile, net neutrality advocates in Congress are pondering new legislation for two reasons: First, there is a debate about whether the FCC currently has enough authority to enforce a net neutrality rule. Second, regardless of whether the Commission has such authority today or doesn’t, some would rather see net neutrality rules etched into statute than leave them to the uncertainties of the rulemaking process under this and future Commissions.

One legislative proposal comes from Rep. Ed Markey and colleagues. Called the Internet Freedom Preservation Act of 2009, its current draft is available on the Free Press web site.

I favor the broad goals that motivate this bill — an Internet that remains friendly to innovation and broadly available. But I personally believe the current draft of this bill would be a mistake, because it embodies a very optimistic view of the FCC’s ability to wield regulatory authority and avoid regulatory capture, not only under the current administration but also over the long-run future. It puts a huge amount of statutory weight behind the vague-till-now idea of “reasonable network management” — something that the FCC’s policy statement (and many participants in the debate) have said ISPs should be permitted to do, but whose meaning remains unsettled. Indeed, Ed raised questions back in 2006 about just how hard it might be to decide what this phrase should mean.

The section of the Markey bill that would be labeled as section 12 (d) in statute says that a network management practice

. . . is a reasonable practice only if it furthers a critically important interest, is narrowly tailored to further that interest, and is the means of furthering that interest that is the least restrictive, least discriminatory, and least constricting of consumer choice available.

This language — particularly the trio of “leasts” — puts the FCC in a position to intervene if, in the Commission’s judgment, any alternative course of action would have been better for consumers than the one an ISP actually took. Normally, to call something “reasonable” means that it is within the broad range of possibilities that might make sense to an imagined “reasonable person.” This bill’s definition of “reasonable” is very different, since on its terms there is no scope for discretion within reasonableness — the single best option is the only one deemed reasonable by the statute.

The bill’s language may sound familiar — it is a modified form of the judicial “strict scrutiny” standard the courts use to review government action when the state uses a suspect classification (such as race) or burdens a fundamental right (such as free speech in certain contexts). In those cases, the question is whether or not a “compelling governmental interest” justifies the policy under review. Here, however, it’s not totally clear whose interest, in what, must be compelling in order for a given network management practice to count as reasonable. We are discussing the actions of ISPs, who are generally public companies– do their interests in profit maximization count as compelling? Shareholders certainly think so. What about their interests in R&D? Or, does the statute mean to single out the public’s interest in the general goods outlined in section 12 (a), such as “protect[ing] the open and interconnected nature of broadband networks” ?

I fear the bill would spur a food fight among ISPs, each of whom could complain about what the others were doing. Such a battle would raise the probability that those ISPs with the most effective lobbying shops will prevail over those with the most attractive offerings for consumers, if and when the two diverge.

Why use the phrase “reasonable network management” to describe this exacting standard? I think the most likely answer is simply that many participants in the net neutrality debate use the phrase as a shorthand term for whatever should be allowed — so that “reasonable” turns out to mean “permitted.”

There is also an interesting secondary conversation to be had here about whether it’s smart to bar in statue, as the Markey bill would, “. . .any offering that. . . prioritizes traffic over that of other such providers,” which could be read to bar evenhanded offers of prioritized packet routing to any customer who wants to pay a premium, something many net neutrality advocates (including, e.g. Prof. Lessig) have said they think is fine.

My bottom line is that we ought to speak clearly. It might or might not make sense to let the FCC intervene whenever it finds ISPs’ network management to be less than perfect (I think it would not, but recognize the question is debatable). But whatever its merits, a standard like that — removing ISP discretion — deserves a name of its own. Perhaps “least restrictive network management” ?

Cross-posted at the Yale ISP Blog.

Filed Under: Broadband Tagged With: ,