Category Archives: Social networks

Cloudy with a Chance of Privacy

Three Paper Thursday is an experimental new feature in which we highlight research that group members find interesting.

When new technologies become popular, we privacy people are sometimes miffed that nobody asked for our opinions during the design phase. Sometimes this leads us to make sweeping generalisations such as “only use the Cloud for things you don’t care about protecting” or “Facebook is only for people who don’t care about privacy.” We have long accused others of assuming that the real world is incompatible with privacy, but are we guilty of assuming the converse?

On this Three Paper Thursday, I’d like to highlight three short papers that challenge these zero-sum assumptions. Each is eight pages long and none requires a degree in mathematics to understand; I hope you enjoy them.

Continue reading Cloudy with a Chance of Privacy

Metrics for dynamic networks

There’s a huge literature on the properties of static or slowly-changing social networks, such as the pattern of friends on Facebook, but almost nothing on networks that change rapidly. But many networks of real interest are highly dynamic. Think of the patterns of human contact that can spread infectious disease; you might be breathed on by a hundred people a day in meetings, on public transport and even in the street. Yet if we were facing a flu pandemic, how could we measure whether the greatest spreading risk came from high-order static nodes, or from dynamic ones? Should we close the schools, or the Tube?

Today we unveiled a paper which proposes new metrics for centrality in dynamic networks. We wondered how we might measure networks where mobility is of the essence, such as the spread of plague in a medieval society where most people stay in their villages and infection is carried between them by a small number of merchants. We found we can model the effects of mobility on interaction by embedding a dynamic network in a larger time-ordered graph to which we can apply standard graph theory tools. This leads to dynamic definitions of centrality that extend the static definitions in a natural way and yet give us a much better handle on things than aggregate statistics can. I spoke about this work today at a local workshop on social networking, and the paper’s been accepted for Physical Review E. It’s joint work with Hyoungshick Kim.

Can we Fix Federated Authentication?

My paper Can We Fix the Security Economics of Federated Authentication? asks how we can deal with a world in which your mobile phone contains your credit cards, your driving license and even your car key. What happens when it gets stolen or infected?

Using one service to authenticate the users of another is an old dream but a terrible tar-pit. Recently it has become a game of pass-the-parcel: your newspaper authenticates you via your social networking site, which wants you to recover lost passwords by email, while your email provider wants to use your mobile phone and your phone company depends on your email account. The certification authorities on which online trust relies are open to coercion by governments – which would like us to use ID cards but are hopeless at making systems work. No-one even wants to answer the phone to help out a customer in distress. But as we move to a world of mobile wallets, in which your phone contains your credit cards and even your driving license, we’ll need a sound foundation that’s resilient to fraud and error, and usable by everyone. Where might this foundation be? I argue that there could be a quite surprising answer.

The paper describes some work I did on sabbatical at Google and will appear next week at the Security Protocols Workshop.

Digital Activism Decoded: The New Mechanics of Change

The book “Digital Activism Decoded: The New Mechanics of Change” is one of the first on the topic of digital activism. It discusses how digital technologies as diverse as the Internet, USB thumb-drives, and mobile phones, are changing the nature of contemporary activism.

Each of the chapters offers a different perspective on the field. For example, Brannon Cullum investigates the use of mobile phones (e.g. SMS, voice and photo messaging) in activism, a technology often overlooked but increasingly important in countries with low ratios of personal computer ownership and poor Internet connectivity. Dave Karpf considers how to measure the success of digital activism campaigns, given the huge variety of (potentially misleading) metrics available such as page impression and number of followers on Twitter. The editor, Mary Joyce, then ties each of these threads together, identifying the common factors between the disparate techniques for digital activism, and discussing future directions.

My chapter “Destructive Activism: The Double-Edged Sword of Digital Tactics” shows how the positive activism techniques promoted throughout the rest of the book can also be used for harm. Just as digital tools can facilitate communication and create information, they can also be used to block and destroy. I give some examples where these events have occurred, and how the technology to carry out these actions came to be created and deployed. Of course, activism is by its very nature controversial, and so is where to draw the line between positive and negative actions. So my chapter concludes with a discussion of the ethical frameworks used when considering the merits of activism tactics.

Digital Activism Decoded, published by iDebate Press, is now available for download, and can be pre-ordered from Amazon UK or Amazon US (available June 30th now).

Update (2010-06-17): Amazon now have the book in stock at both their UK and US stores.

Digital Activism Decoded

What's the Buzz about? Studying user reactions

Google Buzz has been rolled out to 150M Gmail users around the world. In their own words, it’s a service to start conversations and share things with friends. Cynics have said it’s a megalomaniacal attempt to leverage the existing user base to compete with Facebook/Twitter as a social hub. Privacy advocates have rallied sharply around a particular flaw: the path of least-resistance to signing up for Buzz includes automatically following people based on Buzz’s recommendations from email and chat frequency, and this “follower” list is completely public unless you find the well-hidden privacy setting. As a business decision, this makes sense, the only chance for Buzz to make it is if users can get started very quickly. But this is a privacy misstep that a mandatory internal review would have certainly objected to. Email is still a private, personal medium. People email their mistresses, workers email about job opportunities, reporters email anonymous sources all with the same emails they use for everything else. Besides the few embarrassing incidents this will surely cause, it’s fundamentally playing with people’s perceptions of public and private online spaces and actively changing social norms, as my colleague Arvind Narayanan spelled out nicely.

Perhaps more interesting than the pundit’s responses though is the ability to view thousands of user’s reactions to Buzz as they happen. Google’s design philosophy of “give minimal instructions and just let users type things into text boxes and see what happens” preserved a virtual Pompeii of confused users trying to figure out what the new thing was and accidentally broadcasting their thoughts to the entire Internet. If you search Buzz for words like “stupid,” “sucks,” and “hate” the majority of the conversation so far is about Buzz itself. Thoughts are all over the board: confusion, stress, excitement, malaise, anger, pleading. Thousands of users are badly confused by Google’s “follow” and “profile” metaphors. Others are wondering how this service compares to the competition. Many just want the whole thing to go away (leading a few how-to guides) or are blasting Google or blasting others for complaining.

It’s a major data mining and natural language processing challenge to analyze the entire body of reactions to the new service, but the general reaction is widespread disorientation and confusion. In the emerging field of security psychology, the first 48 hours of Buzz posts could provide be a wealth of data about about how people react when their privacy expectations are suddenly shifted by the machinations of Silicon Valley.

The need for privacy ombudsmen

Facebook is rolling out two new features with privacy implications, an app dashboard and a gaming dashboard. Take a 30 second look at the beta versions which are already live (with real user data) and see if you spot any likely problems. For the non-Facebook users, the new interfaces essentially provide a list of applications that your friends are using, including “Recent Activity” which lists when applications were used. What could possibly go wrong?

Well, some users may use applications they don’t want their friend to know about, like dating or job-search. And they certainly may not want others to know the time they used an application, if this makes it clear that they were playing a game on company time. This isn’t a catastrophic privacy breach, but it will definitely lead to a few embarrassing situations. As I’ve argued before, users should have a basic privacy expectation that if they continue to use a service in a consistent way, data won’t be shared in a new, unexpected manner of which they have no warning or control, and this new feature violates that expectation. The interesting thing is how Facebook is continually caught by surprise when their spiffy new features upset users. They seem equally clueless with their response: allowing developers to opt an application out of appearing on the dashboard. Developers have no incentive to do this, as they want maximum exposure for their apps. A minimally acceptable solution must allow users to opt themselves out.

It’s inexcusable that Facebook doesn’t appear to have a formal privacy testing process to review new features and recommend fixes before they go live. The site is quite complicated, but a small team should be able to identify the issues with something like the new dashboard in a day’s work. It could be effective with with 1% of the manpower of the company’s nudity cops. Notably, Facebook is trying to resolve a class-action lawsuit over their Beacon fiasco by creating an independent privacy foundation, which privacy advocates and users have both objected to. As a better way forward, I’d call for creating an in-house “privacy ombudsmen” team, which has the authority to review new features and publish analysis of them, as a much more direct step to preventing future privacy failures.

Facebook tosses graph privacy into the bin

Facebook has been rolling out new privacy settings in the past 24 hours along with a “privacy transition” tool that is supposed to help users update their settings.  Ostensibly, Facebook’s changes are the result of pressure from the Canadian privacy commissioner, and in Facebook’s own words the changes are meant to be “new tools to control your experience.” The changes have been harshly criticized in a number of high-profile places:  the New York Times, Wired, CnetTechCrunch, Valleywag, ReadWriteWeb, and by the the EFF and the ACLU. The ACLU has the most detailed technical summary of changes, essentially there are more granular controls but many more things will default to “open to everyone.” It’s most telling to check the blogs used by Facebook developers and marketers with a business interest in the matter. Their take is simple: a lot more information is about to be shared and developers need to find out how to use it.

The most discussed issue is the automatic change to more open-settings, which will lead to privacy breaches of the socially-awkward variety, as users will accidentally post something that the wrong person can read. This will assuredly happen more frequently as a direct result of these changes, even though Facebook is trying to force users to read about the new settings, it’s a safe bet that users won’t read any of it. Many people learn how Facebook works by experience, they expect it to keep working that way and it’s a bad precedent to change that when it’s not necessary. The fact that Facebook’s “transition wizard” includes one column of radio buttons for “keep my old settings” and a pre-selected column for “switch to the new settings Facebook wants me to have” shows that either they don’t get it or they really don’t respect their users. Most of this isn’t surprising though: I wrote in June that Facebook would be automatically changing user settings to be more open, TechCrunch also saw this coming in July.

There’s a much more surprising bit which has been mostly overlooked-it’s now impossible for any user to hide their friend list from being globally viewable to the Internet at large. Facebook has a few shameful cop-out statements about this, stating that you can remove it from your default profile view if you wish, but since (in their opinion) it’s “publicly available information”  you can’t hide it from people who really want to see it. It has never worked this way previously, as hiding one’s friend list was always an option, and there have been many research papers, including a few by me and colleagues in Cambridge, concluding that the social graph is actually the most important information to keep private. The threats here are more fundamental and dangerous-unexpected inference of sensitive information, cross-network de-anonymisation, socially targeted phishing and scams.

It’s incredibly disappointing to see Facebook ignoring a growing body of scientific evidence and putting its social graph up for grabs. It will likely be completely crawled fairly soon by professional data aggregators, and probably by enterprising researchers soon after. The social graph is powerful view into who we are—Mark Zuckerberg said so himself—and  it’s a sad day to see Facebook cynically telling us we can’t decide for ourselves whether or not to share it.

UPDATE 2009-12-11: Less than 12 hours after publishing this post, Facebook backed down citing criticism and made it possible to hide one’s friend list. They’ve done this in a laughably ham-handed way, as friend-list visibility is now all-or-nothing while you can set complex ACLs on most other profile items. It’s still bizarre that they’ve messed with this at all, for years the default was in fact to only show your friend list to other friends. One can only conclude that they really want all users sharing their friend list, while trying to appear privacy-concerned: this is precisely the “privacy communication game” which Sören Preibusch and I wrote of in June. This remains an ignoble moment for Facebook-the social graph will still become mostly public as they’ll be changing overnight the visibility of hundreds of millions of users’ friends lists who don’t find this well-hidden opt-out.

User complaints about photos in Facebook ads

I wrote about the mess caused by Facebook’s insecure application platform nearly 2 months ago. I also wrote about the long-term problems with “informed consent” for data use in social networks. In the past week, both problems came to a head as users began complaining about multiple third-party ad networks using their photos in banner ads. When I mentioned this problem in June, Facebook had just shut down the biggest ad networks for “deceptive practices,” specifically by duping users into a US$20 per month ringtone subscription. The void created by banning SocialReach and SocialHour apparently led to many new advertisers popping up in their place, with most carrying on the practice of using user photos to hawk quizzes, dating services, and the like. The ubiquitous ads annoyed enough users that Facebook was convinced to ban advertisers from using personal data. This is a welcome move, but Facebook underhandedly inserted a curious new privacy setting at “Privacy Settings->News Feed and Wall->Facebook Ads”:

Facebook does not give third party applications or ad networks the right to use your name or picture in ads. If this is allowed in the future, this setting will govern the usage of your information.

With this change, Facebook has quietly reserved the right to re-allow applications to utilise user data in ads in the future and opted everybody in to the feature. We’ve written about social networks minimising privacy salience, but this is plainly deceptive. It’s hard not to conclude this setting was purposefully hidden from sight, as ads shown by third-party applications have nothing to do with the News Feed or Wall. The choices of “No One” or “Only Friends” are also obfuscating, as only friends’ applications can access data from Facebook’s API to begin with; this is a simple “opt-out” checkbox dressed up to making being opted in seem more private. Meanwhile, Facebook has been showing users a patronising popup message on log-in:

Worried about privacy? Your photos are safe. There have been misleading rumors recently about the use of your photos in ads. Don’t believe them. These rumors were related to third-party applications, and not ads shown by Facebook. Get the whole story at the Facebook Blog, or check out the Help Center.

This message is misleading, if not outright dishonest, and shows an alarming dismissal of what was a widespread practice that offended many users. People weren’t concerned with whether their photos were sent to advertisers by Facebook itself or third-parties. They don’t want their photos or names used or stored by advertisers regardless of the technical details. The platform API remains fundamentally broken and gives users no way to prevent applications from accessing their photos. Facebook would be best served by fixing this instead of dismissing users’ concern for privacy as “misleading rumors.”