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At the crossroads of technology and policy

Ubiquity, Volume 2003 Issue February, February 1 - February 28, 2003 | BY Ubiquity staff 


Full citation in the ACM Digital Library

Lorrie Cranor on privacy, online voting and Internet censorship.

Lorrie Cranor on privacy, online voting and Internet censorship.

Dr. Lorrie Faith Cranor is a Principal Technical Staff Member at AT&T Labs-Research, where she has done work in a variety of areas where technology and policy issues interact -- including online privacy, electronic voting and spam. She is chair of the Platform for Privacy Preferences Project (P3P) Specification Working Group at the World Wide Web Consortium and author of the book Web Privacy with P3P (O'Reilly 2002).

UBIQUITY: Let's start with a quote from your Web site: "It's always difficult to explain what field I'm in." Why is it difficult, and what field are you in?

CRANOR: I think of my work as being at the intersection of multiple areas, so I never fit into one particular box. My work involves knowledge of both the technical and social aspects of things. Some of the labels people have used to describe this kind of work include social informatics and value-sensitive design. Both of those are reasonable labels for a lot of what I do, but most people don't really know what they mean. So while appropriate, they don't really give the whole picture.

UBIQUITY: How do you explain your interest in privacy?

CRANOR: I'm interested in privacy as it relates to technology. There are a variety of aspects of that. One is how technologies often erode privacy, and thinking about ways to prevent erosion of privacy. Another aspect is looking at ways that technology could help increase privacy. It's not enough just to know a lot about privacy. You should know the philosophical underpinnings and the policy issues. It's not enough to understand the technology. You need to think about both areas. They go together.

UBIQUITY: Can you give a good example of the intersection between privacy and technology?

CRANOR: During the past few years I've spent a lot of time on a project called P3P, the Platform for Privacy Preferences. With P3P, our goal was to create a computer-readable way for Websites to describe their privacy policies so that users wouldn't have to read the long legalese privacy statements at every Website. The project was developed by the World Wide Web consortium. Two groups of people worked on it. There was a group of lawyers and policy advocates, and there was a group of technology people. The technology people focused on the technical mechanism necessary to make it work. The policy people focused on the vocabulary that was used to talk about privacy.

UBIQUITY: Which group did you belong to?

CRANOR: Throughout much of this project I was the interface between these two groups. I went back and forth between them. Sometimes the technical group would push back on the policy group and say, "These things that you want in the vocabulary don't make sense from a technical perspective. So get rid of them." And the vocabulary people would say, "How can we get rid of them? These are really important." Having the understanding of both sides was helpful in working out solutions; figuring out what was important from the policy perspective and figuring out ways of dealing with it technically.

UBIQUITY: Does the average person on the street worry much about privacy?

CRANOR: I think privacy is one of the things that everybody cares about, at least in Western societies. Do they worry about it? It depends upon their knowledge of how their privacy might be invaded. I think a lot of people are unaware of how easily their privacy might be invaded. But once that has been pointed out to them, most people don't like it.

UBIQUITY: How easy would it be for an individual with wicked intentions to invade the files on somebody attached to the Internet? For example, say you wanted to find out where the person searched on the Web. I know there's no quantitative answer to that, but give it a stab.

CRANOR: You can find out a lot if you know a few key pieces of information. For example, if I know somebody's Social Security number, then with some skill at impersonation, I can easily access financial records, health records and various other records. As far as getting somebody's clicks out of the computer, it depends on the circumstances. How do they access the Internet? Does their ISP keep records of those sorts of things? Can I install monitoring software on their computer?

UBIQUITY: How easy is it to get to somebody's hard disk?

CRANOR: It depends on how well the computer is secured and how you access the Internet. It's fairly difficult to access files on a computer that uses a dial-up modem. For example, someone might e-mail an attachment that included software that would cause the computer to automatically e-mail the files back to the attacker. But that would only work if the recipient opened the attachment. That's one way it could be done. Or an attacker might exploit browser bugs and lure someone into visiting a certain site. For people who have broadband connections, if they haven't put up personal firewalls, and depending on their operating system, it may be very easy for somebody to get on their hard drive. If you don't have your sharing settings set appropriately, then one of your neighbors could click on their Microsoft neighborhood and get on your hard drive.

UBIQUITY: Do you think that the danger that is suggested by the movies and the popular press is exaggerated?

CRANOR: I think there are specific episodes in a lot of movies that are exaggerated. But the overall danger is quite real. I view this issue of people getting on to your hard drive as more of a security issue than a privacy issue. It is more or less solvable by using good security software. The more interesting problems from the privacy perspective are the issues of where we have massive databases that provide useful functions for people. If you pull together information from different data bases, you can basically build up files on people, and from all those bits of data, derive new pieces of information.

UBIQUITY: Have you seen any real life examples of this?

CRANOR: One example comes from a professor at Carnegie Mellon University, Latanya Sweeny, who did a study where she accessed a drivers' license database. She was able to demonstrate that with small pieces of information, not a first name, you could uniquely identify people. For example, with somebody's date of birth and their zip code, she uniquely identified something like 99 percent of the people in Cambridge, Massachusetts. By putting those two pieces of information together somebody can figure out who you are pretty easily.

UBIQUITY: How would you characterize the main problem in online privacy? What's the root of all this difficulty?

CRANOR: Look at what distinguishes online privacy issues from off-line privacy issues. In some ways there's nothing new. We've had privacy concerns forever. But with online privacy issues what is added is the ability to quickly and easily connect databases that are not physically located in the same place. Computerization allows us to easily search multiple databases together. It used to be that if I wanted records about somebody, I had to drive to the town hall, go through the file cabinets and pull out records. If a person moved around, I'd have to go to each of the town halls in all the places he or she lived, and pull out birth certificates, tax records and all that stuff. Now, all that information is online. You can get it without leaving your house, if you know how to look for it.

UBIQUITY: Let me refer back to you. You did your doctorate on voting. Is there a good connection there?

CRANOR: I looked at electronic voting, which is again an issue concerning the combination of technical and the social issues. One aspect of my work on voting was that we have secret ballots. We want privacy in the ballot boxes. So I did some privacy-related work as part of that.

UBIQUITY: In your work at AT&T Labs, are you focused primarily on online privacy? What specific goal are you working toward?

CRANOR: For the past five years or so my goal has been to finish the P3P specification, which I did. Not just me personally, but the whole working group at W3C. And I wrote a book about it that was published by O'Reilly a few months ago. Now I'm tying up some loose ends related to P3P. We had developed some P3P software here at AT&T. We're currently working on a new version of that. But thinking more long-term, I've gotten very interested in how to make privacy software, or privacy tools, accessible to users, because privacy is a fuzzy, difficult concept. It's not obvious how to build good software that's related to privacy, or also security. I'm looking generally at those sorts of issues.

UBIQUITY: You said before that everybody appreciates and values privacy. Do you think that they generally value other people's privacy? For instance, do they think that surveillance tools in public places put forth any kind of a problem? Or are people in general fairly blasé about that?

CRANOR: I think it varies. We know most of these things from the various public-opinion surveys that are done. Certainly the responses you get change right after there's been some sort of scary event. Right after September 11, people seemed more willing to give up some privacy. Now, I believe most of the polls show that it's swinging back the other way. I think some people are quick to say, "Given this event, we're willing to put in whatever safeguards are needed, even if that means giving up privacy." There are other people who will say, "No, it's not worth the tradeoff." I also think there are many things that are put in place in the name of security or safety that force us to give up privacy, but it's not clear that they actually increase our security or safety.

UBIQUITY: Let's dwell a minute over the word privacy, which I'm sure you've given a lot of thought to. Is there a right to privacy when you're going down an escalator in a public building? Do you have a right not to have your picture taken?

CRANOR: Well first you have to back up and say, "Is there a right to privacy?"

UBIQUITY: Go ahead, let's do that.

CRANOR: In some countries there is a right to privacy that's written into the constitution or laws. In the US that is not the case. There is no explicit Constitutional right to privacy, although we do have some Constitutional rights to some aspects of privacy. Many people argue that even if we don't constitutionally have that right, we should have privacy as a fundamental human right. Getting back to the question of do you have a right to privacy in a public building, it depends on what you mean by that. If you're talking about having a picture taken of your face in a public building, I believe that US law would say that you don't have a right to privacy in that context.

UBIQUITY: What do the privacy advocacy groups say about this? Do they assert that there is a right to privacy in a public place, or that there should be a right?

CRANOR: It also depends on who's taking the picture. There's a difference between whether the private business owner is taking the picture, or whether the police are taking the picture. It also depends on what happens to the picture. Many businesses have surveillance cameras all over the place that they never look at unless a crime is committed in which case, they'll pull the tapes and investigate it. But there's also a situation like the police setting up cameras and taking pictures of everybody who goes in to watch the Super Bowl. I think the privacy advocacy groups have different reactions to these two situations.

UBIQUITY: Because of the motive?

CRANOR: In part because of the motive, but also in part because of how the information is used. In the Super Bowl case, the idea is to use technology that is rather faulty to begin with to identify the faces of potential terrorists. In part, due to how bad the technology is, the system doesn't really work. It will have many false positives. Looking at faces of people when 99.99 percent or perhaps even 100 percent are completely innocent in the hopes of finding a terrorist is very different than reviewing surveillance camera tapes when a crime has actually been committed.

UBIQUITY: Conversationally you say tapes, but isn't it quite rapidly converting to digital files?

CRANOR: Yes, in some cases it might be digital and in some cases it might be tape.

UBIQUITY: Theoretically they could keep this information for a long time.

CRANOR: It's not so much how long it's kept as to how it's accessed. Let's say that we have a store that keeps tapes. They don't rewrite the tapes, they keep them forever. They have a huge closet they just keep throwing the tapes into. Soon they have 10 years' worth of tapes. It would be very difficult to go back and find something that happened three years and 29 days ago. They would need a very specific reason to look on a specific date for something. Otherwise, the only way to find something is to have somebody sit there in real time and look through tape after tape after tape. If you have all of these tapes digitized and you have tools that let you automatically scan the images looking for something, it makes the information a lot more accessible. Now it can be used for more speculative hunting instead of a very targeted investigation.

UBIQUITY: What's your personal opinion about this? In other words, are you very strongly on one side or the other on the value of these surveillance kinds of technologies, such as retina scanning, or are you in somewhere the middle?

CRANOR: I think I come down fairly strongly on the privacy protection/anti-surveillance side, although perhaps not as strongly as some of the more extreme privacy activists.

UBIQUITY: Are the most extremist, to use your phrase, completely against any of these technologies?

CRANOR: It's not just being for or against the technology. It's a combination of technology and laws and a whole package of things. An extreme view on one end would be to say there should be no surveillance and we should have laws in the US that guarantee a right to privacy in all situations. There are people who feel fairly strongly that we need to have legislative guarantees of privacy and we should have very minimal or no surveillance technology. My feeling is that we should be very cautious when using surveillance technologies. I wouldn't say that there's no place for them, but I think they tend to be overused. And they tend to be used inappropriately.

UBIQUITY: Let me ask you about an event that was in the news recently about a small elementary school, I believe it was in London. The school is introducing retinal scanning in the school cafeteria. The punch line is that the reason for doing it was completely benign, if you can believe the people. It was to prevent insensitive kids from embarrassing poor kids who don't have the money to pay for their lunches.

CRANOR: So basically they are arguing that will protect the privacy of the poor kids.

UBIQUITY: Do you buy that?

CRANOR: Yes and no. Certainly I think it's a good idea to protect the privacy of the poor kids. I'm not so sure about doing it with retinal scan technology that could potentially be a privacy invasion. Biometrics technology has multiple uses. There wasn't enough information in the media reports to know fully what kind of system they were using. The problem with a lot of these systems is that they keep a database of the biometrics information. If somebody were to break into and steal that database, they would have all of this information about the kids' retinas. In the future when these kids become adults there may be other applications of retina scans. The person who stole the retina database now has basically the password needed to get into these other systems. That would be a bad thing. On the other hand, there are ways of implementing biometrics systems where you never actually store that biometrics identifier. It gets encrypted and used in a way that won't allow you to impersonate somebody in the future. I also have a lot of concerns about having it deployed in a low security area such as an elementary school. The people there aren't necessarily experts in using biometrics technology. It's possible that it's being done perfectly well, but I'm very skeptical.

UBIQUITY: Let's move to the topic of your dissertation, and for that matter to the general topic of your first appearance in Ubiquity. You did research on electronic voting. Briefly explain the thrust of the research.

CRANOR: There were basically two aspects to the research that I did. The first aspect was trying to figure out the logistics of building a technical implementation of an Internet voting system that would protect people's privacy, while at the same time making sure that people could only vote once and only eligible voters could vote.

UBIQUITY: What was the other aspect?

CRANOR: The other aspect was voting theory work that looked at developing a new type of voting system that allowed people to basically cast a contingent vote. So in an election where you have three or more candidates, sometimes, it's not advantageous to vote for your first choice if your first choice doesn't have much of a chance of winning. But if you would like to vote for your second choice, because that might influence the outcome of the election, but you'd also like to vote for your first choice so you get it on the record that that person had some support. So I developed a type of voting system that would allow that.

UBIQUITY: I believe that some voting theorists have opposed this idea. It's strongly asserted that a system that has a lot of runoffs when no candidate gets 50 percent of the vote is anti-minority because a minority will almost never get 50 percent of the vote. So it effectively says that minorities will not to get elected.

CRANOR: Yes, to some extent. I think it becomes more of an issue in the case where you're electing multiple people, say, a town council. One way to do it is to have all of the seats be general seats. And the other way to do it is to divide the town into districts. Let's say 20 percent of your population is African American, spread evenly throughout the town. If your town is divided into districts, then 20 percent of the people in every district will be African American. If we assume that people always vote for the person of their same race then no African Americans will ever win. In the case of general seats -- let's say there are five seats and 20 percent of the town is African American -- the African American voters will win one seat.

UBIQUITY: On the more general question of Internet voting, how is it progressing? Will it be a significant reality?

CRANOR: I am afraid that Internet voting will be a reality, and I think it's a bad idea, which surprises people. Usually people think that because I have done Internet voting work, I must be excited that Internet voting is progressing. It's one of those things that the more you know about, the less you like it.

UBIQUITY: What do you dislike about Internet voting?

CRANOR: For one thing, there are huge security risks, especially when people are talking about Internet voting from home or from work as opposed to, say, going to a polling place that happens to be connected to the Internet. That's no fun. If we have to go to the polling place it really doesn't matter if it's connected to the Internet or whatever because we still had to go to a polling place. So when people, especially in the press, talk about Internet voting they're talking about voting from anywhere; from home in your pajamas is the classic example. That means voting over the existing insecure Internet using the existing insecure computers in my house that might have viruses or mis-installed software on them. I think that it is really dangerous, especially in elections where there's something really important at stake.

UBIQUITY: Are there cases where Internet voting has been done successfully?

CRANOR: There has been a lot of experimentation with Internet voting. It's been used fairly successfully for some association elections, stockholder elections and things like that. Electronic voting supporters point to these as evidence that it works. But there wasn't much at stake in those elections. There wasn't much of a reason for malicious people to disrupt those sorts of elections. There are also many examples of elections that haven't worked. It's typically not due to security problems, but due to either the software malfunctioning or user interface issues; users just not being able to figure out how to make it work.

UBIQUITY: Do you think of these problems as essentially unsolvable? Or will they be solved a few years from now?

CRANOR: I don't like to say that problems are unsolvable. But I think that in order to have the kind of comfort level that I would like to have in the security of the system, we need a major change in the type of infrastructure that we would be using. That is, we need people to have computers in their homes that are more secure devices than what we currently have. And we need an Internet infrastructure that's more reliable.

UBIQUITY: Is it possible that your fear or distaste for Internet voting is as much derived from social policy as it is from technology problems?

CRANOR: Yes. There definitely are some social issues as well. One thing that comes up is, why are people excited about Internet voting in the first place? Often people say that it will increase voter turnout because it will be easier for people to vote, so more people will participate. Well, there's very little evidence to show that that would actually happen. There have been a number of attempts to increase voter turnout -- increasing the number of hours that the polls are open, increasing the number of polling places, and various other initiatives. What they find is that the people who voted in previous elections love this, because it makes it easier for them to vote in the next election. But the people who didn't vote in the previous election still don't vote. So it's not clear that having Internet voting would, in fact, encourage more people to actually vote.. Or if it did encourage additional voters, are those people who are not willing to take the time to go to a polling place be willing to educate themselves about the issues that they're voting on. So it's not clear that there is a social benefit to Internet voting.

UBIQUITY: What is Publius?

CRANOR: Publius is a system that Avi Rubin, Marc Waldman and I developed to allow people to publish information on the Web in a way that makes it very difficult to censor. Avi was one of my colleagues here at AT&T, and Marc Waldman was a student at NYU.

UBIQUITY: How is it being received?

CRANOR: We did a public trial where we released the software and set up servers to let people play with the system, and it was very interesting. A lot of civil libertarians thought this was just wonderful. We had a lot of positive press articles and won a Freedom of Expression award for this. But some people said that we were irresponsible to put out such a system. There was an article in "Scientific American" that had our pictures, and, under it, it labeled us as being irresponsible.

UBIQUITY: Why irresponsible?

CRANOR: Because we developed a system where anybody could publish anything, and it would be very difficult for it to be stopped. People suggested all sorts of nasty things that might be published that people might be outraged about and asked, "Well, did you think of that?" It is a double-edged sword, but we feel that on balance it is better to allow people to publish ideas. You can always refute objectionable things with more ideas.

UBIQUITY: Where does that stand now?

CRANOR: Our prototype system is available for people to play with. Marc Waldman has continued to work on new systems that grew out of Publius. Publius was one of the first censorship-resistant publishing systems. I think it inspired many others to do work in this area and develop even better systems. It was also one of the peer-to-peer systems to come out around the time when peer-to-peer was closely associated with music swapping, and it demonstrated that there are other uses for peer-to-peer.


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