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Facebook and the Campus Cops

March 20, 2006 by

An interesting mini-controversy developed at Princeton last week over the use of the Facebook.com web site by Princeton’s Public Safety officers (i.e., the campus police).

If you’re not familiar with Facebook, you must not be spending much time on a college campus. Facebook is a sort of social networking site for college students, faculty and staff (but mostly students). You can set up a home page with your picture and other information about you. You can make links to your friends’ pages, by mutual consent. You can post photos on your page. You can post comments on your friends’ pages. You can form groups based on some shared interest, and people can join the groups.

The controversy started with a story in the Daily Princetonian revealing that Public Safety had used Facebook in two investigations. In one case, a student’s friend posted a photo of the student that was taken during a party in the student’s room. The photo reportedly showed the student hosting a dorm-room party where alcohol was served, which is a violation of campus rules. In another case, there was a group of students who liked to climb up the sides of buildings on campus. They had set up a building-climbers’ group on Facebook, and Public Safety reportedly used the group to identify the group’s members, so as to have Serious Discussions with them.

Some students reacted with outrage, seeing this as an invasion of privacy and an unfair tactic by Public Safety. I find this reaction really interesting.

Students who stop to think about how Facebook works will realize that it’s not very private. Anybody with a princeton.edu email address can get an account on the Princeton Facebook site and view pages. That’s a large group, including current students, alumni, faculty, and staff. (Public Safety officers are staff members.)

And yet students seem to think of Facebook as somehow private, and they continue to post lots of private information on the site. A few weeks ago, I surfed around the site at random. Within two or three minutes I spotted Student A’s page saying, in a matter of fact way, that Student A had recently slept with Student B. Student B’s page confirmed this event, and described what it was like. Look around on the site and you’ll see many descriptions of private activities, indiscretions, and rule-breaking.

I have to admit that I find this pretty hard to understand. Regular readers of this blog know that I reveal almost nothing about my personal life. If you have read carefully over the last three and a half years, you have learned that I live in the Princeton area, am married, and have at least one child (of unspecified age(s)). Not exactly tabloid material. Some bloggers say more – a lot more – but I am more comfortable this way. Anyway, if I did write about my personal life, I would expect that everybody in the world would find out what I wrote, assuming they cared.

It’s easy to see why Public Safety might be interested in reading Facebook, and why students might want to keep Public Safety away. In the end, Public Safety stated that it would not hunt around randomly on Facebook, but it would continue to use Facebook as a tool in specific investigations. Many people consider this a reasonable compromise. It feels right to me, though I can’t quite articulate why.

Expect this to become an issue on other campuses too.

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Report: Many Apps Misconfigure Security Settings

February 3, 2006 by

My fellow Princeton computer scientists Sudhakar Govindavajhala and Andrew Appel released an eye-opening report this week on access control problems in several popular applications.

In the old days, operating systems had simple access control mechanisms. In Unix, each file belonged to an owner and a (single) group of users. The owner had the option to give the other group members read and/or write permission, and the option to give everybody read and/or write permission. That was pretty much it.

Over time, things have gotten more complicated. Windows controls access to about fifteen types of objects, with about thirty different flavors of privileges that can each be granted or denied, for any object, to any user or group of users. Privileges can be managed with great precision. In theory, this lets people grant others the absolute minimum privileges they need to do their jobs, which is good security practice.

The downside of this complexity is that if the system is hard to understand, people will make mistakes. End users will surely make mistakes. But you might think that big software companies can manage this complexity and will get the security settings on their products right.

Which brings us to Sudhakar and Andrew’s research. They built an automated tool to analyze the access control settings on files, registry entries, and other objects on a Windows machine. The tool looks at the settings on the machine and applies a set of inference rules that encode the various ways a user could try to leverage his privileges improperly. For example, one rule says that if Alice has the privilege to modify a program, and Bob runs that program, then Alice can use any of Bob’s privileges. (She can do this by adding code to the program that does what she wants; when Bob runs the program, that code will run with Bob’s privileges.) The tool looks for privilege escalation attacks, or ways for a relatively unprivileged user to gain more privilege.

Sudhakar and Andrew ran the tool on professionally-managed Windows systems, and the results were sobering. Several popular applications, from companies like Adobe, AOL, Macromedia, and Microsoft, had misconfigured their access control in ways that allowed relatively unprivileged users – in some cases even the lowliest Guest account – to gain full control of the system.

Sudhakar and Andrew notified the affected vendors well before publishing the paper, and some of the problems they found have been patched. But some problems remain, and testing on new systems tends to find still more problems.

There are two lessons here. First, complicated security mechanisms lead to mistakes, even among relatively sophisticated software developers and companies, so the desire to control privileges precisely must be tempered by the virtue of simplicity. Second, if you’re going to have a complicated system, you probably need tools to help you figure out whether you’re using it safely.

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Do University Honor Codes Work?

October 25, 2005 by

Rick Garnett over at ProfsBlawg asked his readers about student honor codes and whether they work. His readers, who seem to be mostly lawyers and law students, chimed in with quite a few comments, most of them negative.

I have dealt with honor codes at two institutions. My undergraduate institution, Caltech, has a simply stated and all-encompassing honor code that is enforced entirely by the students. My sense was that it worked very well when I was there. (I assume it still does.) Caltech has a small (800 students) and relatively homogeneous student body, with a student culture that features less student versus student competitiveness than you might expect. Competition there tends to be student versus crushing workload. The honor code was part of the social contract among students, and everybody appreciated the benefits it provided. For example, you could take your final exams at the time and place of your choosing, even if they were closed-book and had a time limit; you were trusted to follow the rules.

Contrasting this to the reports of Garnett’s readers, I can’t help but wonder if honor codes are especially problematic in law schools. There is reportedly more cutthroat competition between law students, which could be more conducive to ethical corner-cutting. Competitiveness is an engine of our adversarial legal system, so it’s not surprising to see law students so eager to win every point, though it is disappointing if they do so by cheating.

I’ve also seen Princeton’s disciplinary system as a faculty member. Princeton has a student-run honor code system, but it applies only to in-class exams. I don’t have any first-hand experience with this system, but I haven’t heard many complaints. I like the system, since it saves me from the unpleasant and trust-destroying task of policing in-class exams. Instead, I just hand out the exams, then leave the room and wait nearby to answer questions.

Several years ago, I did a three-year term on Princeton’s Student-Faculty Committee on Discipline, which deals with all serious disciplinary infractions, whether academic or non-academic, except those relating to in-class exams. This was hard work. We didn’t hear a huge number of cases, but it took surprisingly long to adjudicate even seemingly simple cases. I thought this committee did its job very well.

One interesting aspect of this committee was that faculty and students worked side by side. I was curious to see any differences between student and faculty attitudes toward the disciplinary process, but it turned out there were surprisingly few. If anything, the students were on average slightly more inclined to impose stronger penalties than the faculty, though the differences were small and opinions shifted from case to case. I don’t think this reflected selection bias either; discussions with other students over the years have convinced me that students support serious and uniform punishment for violators. So I don’t think there will be much difference in the outcomes of a student-run versus a faculty-run disciplinary process.

One lesson from Garnett’s comments is that an honor code will die if students decide that enforcement is weak or biased. Here the secrecy of disciplinary processes, which is of course necessary to protect the accused, can be harmful. Rumors do circulate. Sometimes they’re inaccurate but can’t be corrected without breaching secrecy. For example, when I was on Princeton’s discipline committee, some students believed that star athletes or students with famous relatives would be let off easier. This was untrue, but the evidence to contradict it was all secret.

Academic discipline seems to have a major feedback loop. If students believe that the secret disciplinary processes are generally fair and stringent, they will be happy with the process and will tend to follow the rules. This leaves the formal disciplinary process to deal with the exceptions, which a good process will be able to handle. Students will buy in to the premise of the system, and most people will be happy.

If, on the other hand, students lose their trust in the fairness of the system, either because of false rumors or because the system is actually unfair, then they’ll lose their aversion to rule-breaking and the system, whether honor-based or not, will break down. Several of Garnett’s readers tell a story like this.

One has to wonder whether it makes much difference in practice whether a system is formally honor-based or not. Either way, students have an ethical duty to follow the rules. Either way, violations will be punished if they come to light. Either way, at least a few students will cheat without getting caught. The real difference is whether the institution conspicuously trusts the students to comply with the rules, or whether it instead conspicuously polices compliance. Conspicuous trust is more pleasant for everybody, if it works.

[Feel free to talk about your own experiences in the comments. I’m especially eager to hear from current or past Princeton students.]

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A Visit From Bill Gates

October 17, 2005 by

Bill Gates visited Princeton on Friday, accompanied by his father, a prominent Seattle lawyer who now heads the Gates Foundation, and by Kevin Schofield, a Microsoft exec (and Princeton alumnus) who helped to plan the university visits.

After speaking briefly with Shirley Tilghman, Princeton’s president, Mr. Gates spent an hour in a roundtable discussion with a smallish group of computer science faculty. I was lucky enough to be one of them. The meeting was closed, so I won’t give you a detailed play-by-play. Essentially, we told him about what is happening in computer science at Princeton; he asked questions and conversation ensued. We talked mostly about computer science education. Along the way I gave a quick description of the new infotech policy course that will debut in the spring. Overall, it was a good, high-energy discussion, and Mr. Gates showed a real passion for computer science education.

After the roundtable, he headed off to Richardson Auditorium for a semi-public lecture and Q&A session. (I say semi-public because there wasn’t space for everybody who wanted to get in; tickets were allocated to students by lottery.) The instructions that came with my ticket made it seem like security in the auditorium would be very tight (no backpacks, etc.), but in fact the security measures in place were quite unobtrusive. An untrained eye might not have noticed anything different from an ordinary event. I showed up for the lecture at the last minute, coming straight from the faculty roundtable, so I one of the worst seats in the whole place. (Not that I’m complaining – I certainly wouldn’t have traded away my seat in the faculty roundtable for a better seat at the lecture!)

After an introduction from Shirley Tilghman, Mr. Gates took the stage. He stood alone on the stage and talked for a half-hour or so. His presentation was punctuated by two videos. The first showed a bunch of recent Princeton alums who work at Microsoft talking about life at Microsoft in a semi-serious, semi-humorous way. (The highlight was seeing Corey in a toga.) The second video was a five-minute movie in which Mr. Gates finds himself in the world of Napoleon Dynamite. It co-stars Jon Heder, who played Napoleon in the movie. I haven’t seen the original movie but I’m told that many of the lines and gags in the video come from the movie. People who know the original movie seem to have found the video funny.

The theme of the lecture was the seamless coolness of the future computing environment. It was heavy on promotion and demonstrations of Microsoft products.

The Q&A was pretty interesting. He was asked how to reconcile his current cheerleading for C.S. education with his own history of dropping out of college. He had a funny and thoughful answer. I assume he’s had plenty of chances to hone his answer to that question.

A student asked him a question about DRM. His answer was fairly general, talking about the importance of both consumer flexibility and revenue for creators. He went on to say some harsh things about Blu-Ray DRM, saying that the system over-restricted consumers’ use and that its content-industry backers were making a mistake by pushing for it.

(At this point I had to leave due to a previous commitment, so from here on I’m relying on reports from people who were there.)

Another student asked him about intellectual property, suggesting that Microsoft was both a beneficiary and a victim of a strong patent system. Mr. Gates said that the patent system is basically sound but could benefit from some tweaking. He didn’t elaborate, but I assume he was referring to patent reform suggestions Microsoft has made previously.

After the Q&A, Mr. Gates accepted the “Crystal Tiger” award from a student group. Then he left for his next university visit, reportedly at Howard University.

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DRM Textbooks Offered to Princeton Students

August 8, 2005 by

There’s a story going around the blogosphere that Princeton is experimenting with DRMed e-textbooks. Here’s an example:

Princeton University, intellectual home of Edward Felten and Alex Halderman, has evidently begun to experiment with DRM’d textbooks. According to this post, there are quite a few digital restrictions being managed:

  • Textbook is locked to the computer where you downloaded it from;
  • Copying and burning to CD is prohibited;
  • Printing is limited to small passages;
  • Unless otherwise stated, textbook activation expires after 5 months (*gasp*);
  • Activated textbooks are not returnable;
  • Buyback is not possible.

There an official press release from the publishers for download here.

Several people have written, asking for my opinion on this.

First, a correction. As far as I can tell, Princeton University has no part in this experiment. The Princeton University Store, a bookstore that is located on the edge of the campus but is not affiliated with the University, will be the entity offering DRMed textbooks. The DRM company’s press release tries to leave the impression that Princeton University itself is involved, but this appears to be incorrect.

In any case, I don’t see a reason to object to the U-Store offering these e-books, as long as students are informed about the DRM limitations and can still get the dead-tree version instead. It’s hard to see the value proposition for students in the DRMed version, unless the price is very low. It appears the price will be about two-thirds of the new-book price, which is obviously a bad deal. Our students are smart enough to know which version to buy – and the faculty will be happy to advise them if they’re not sure.

I don’t object to other people wasting their money developing products that consumers won’t want. People waste their money on foolish schemes every day. I wish for their sake that they would be smarter. But why should I object to this product or try to stop it? A product this weak will die on its own.

The problem with DRM is not that bad products can be offered, but that public policy sometimes protects bad products by thwarting the free market and the free flow of ideas. The market will kill DRM, if the market is allowed to operate.

UPDATE (August 12): The DRM vendor announced yesterday that usage restrictions will be eased somewhat. The expiration time has been extended to at least twelve months (longer for some publishers), and restrictions on printing have been loosened in some cases.

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