Tor Needs Bridges
The Internet anonymity service Tor needs people who are willing to run bridges. It’s a goodness for the world; do it if you can.
Entries Tagged "anonymity"
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Identifying People from their Writing Style
It’s called stylometry, and it’s based on the analysis of things like word choice, sentence structure, syntax and punctuation. In one experiment, researchers were able to identify 80% of users with a 5,000-word writing sample.
Download tools here, including one to anonymize your writing style.
Pseudonymity
Long essay on the value of pseudonymity. From the conclusions:
Here lies the huge irony in this discussion. Persistent pseudonyms aren’t ways to hide who you are. They provide a way to be who you are. You can finally talk about what you really believe; your real politics, your real problems, your real sexuality, your real family, your real self. Much of the support for “real names” comes from people who don’t want to hear about controversy, but controversy is only a small part of the need for pseudonyms. For most of us, it’s simply the desire to be able to talk openly about the things that matter to every one of us who uses the Internet. The desire to be judged—not by our birth, not by our sex, and not by who we work for—but by what we say.
[…]
I leave you with this question. What if I had posted this under my pseudonym? Why should that have made a difference? I would have written the same words, but ironically, I could have added some more personal and perhaps persuasive arguments which I dare not make under this account. Because I was forced to post this under my real name, I had to weaken my arguments; I had to share less of myself. Have you ever met “Kee Hinckley”? Have you met me under my other name? Does it matter? There is nothing real on the Internet; all you know about me is my words. You can look me up on Google, and still all you will know is my words. One real person wrote this post. It could have been submitted under either name. But one of them is not allowed to. Does that really make sense?
Behind every pseudonym is a real person. Deny the pseudonym and you deny the person.
This is, of a course, a response to the Google+ names policy.
The Non-Anonymity of Bubble Forms
It turns out that “fill-in-the-bubble” forms are not so anonymous.
Why it's So Difficult to Trace Cyber-Attacks
I’ve been asked this question by countless reporters in the past couple of weeks. Here’s a good explanation. Shorter answer: it’s easy to spoof source destination, and it’s easy to hijack unsuspecting middlemen and use them as proxies.
No, mandating attribution won’t solve the problem. Any Internet design will necessarily include anonymity.
Realistic Masks
They’re causing problems:
A white bank robber in Ohio recently used a “hyper-realistic” mask manufactured by a small Van Nuys company to disguise himself as a black man, prompting police there to mistakenly arrest an African American man for the crimes.
In October, a 20-year-old Chinese man who wanted asylum in Canada used one of the same company’s masks to transform himself into an elderly white man and slip past airport security in Hong Kong.
Authorities are even starting to think that the so-called Geezer Bandit, a Southern California bank robber believed for months to be an old man, might actually be a younger guy wearing one of the disguises made by SPFXMasks.
News coverage of the incidents has pumped up demand for the masks, which run from $600 to $1,200, according to company owner Rusty Slusser. But he says he’s not happy about it.
[…]
Slusser opened SPFXMasks in 2003. His six-person crew uses silicone that looks and feels like flesh, down to the pores. Each strand of hair and it’s human hair is sewn on individually. Artists methodically paint the masks to create realistic skin tones.
“I wanted to make something that looks so real that when you go out for Halloween no one can tell,” Slusser said. “It’s like ‘Mission: Impossible’ you pull it over your head one time and that’s it. It’s like a 10-hour makeup job in 10 seconds.”
He experimented until he found the right recipe for silicone that would seem like skin. A key discovery was that if the inside of the mask is smooth even if the outside is bumpy with pores, a nose and other features it will stretch over most faces and move with facial muscles.
Haystack
I stayed clear of Haystack—the anonymity program that was going to protect the privacy of dissidents the world over—because I didn’t have enough details about the program to have an intelligent opinion. The project has since imploded, and here are two excellent essays about the program and the hype surrounding it.
Makeup to Fool Face Recognition Software
An NYU student has been reverse-engineering facial recognition algorithms to devise makeup patterns to confuse face recognition software.
De-Anonymizing Social Network Users
Interesting paper: “A Practical Attack to De-Anonymize Social Network Users.”
Abstract. Social networking sites such as Facebook, LinkedIn, and Xing have been reporting exponential growth rates. These sites have millions of registered users, and they are interesting from a security and privacy point of view because they store large amounts of sensitive personal user data.
In this paper, we introduce a novel de-anonymization attack that exploits group membership information that is available on social networking sites. More precisely, we show that information about the group memberships of a user (i.e., the groups of a social network to which a user belongs) is often sufficient to uniquely identify this user, or, at least, to significantly reduce the set of possible candidates. To determine the group membership of a user, we leverage well-known web browser history stealing attacks. Thus, whenever a social network user visits a malicious website, this website can launch our de-anonymization attack and learn the identity of its visitors.
The implications of our attack are manifold, since it requires a low effort and has the potential to affect millions of social networking users. We perform both a theoretical analysis and empirical measurements to demonstrate the feasibility of our attack against Xing, a medium-sized social network with more than eight million members that is mainly used for business relationships. Our analysis suggests that about 42% of the users that use groups can be uniquely identified, while for 90%, we can reduce the candidate set to less than 2,912 persons. Furthermore, we explored other, larger social networks and performed experiments that suggest that users of Facebook and LinkedIn are equally vulnerable (although attacks would require more resources on the side of the attacker). An analysis of an additional five social networks indicates that they are also prone to our attack.
News article. Moral: anonymity is really, really hard—but we knew that already.
Anonymity and the Internet
Universal identification is portrayed by some as the holy grail of Internet security. Anonymity is bad, the argument goes; and if we abolish it, we can ensure only the proper people have access to their own information. We’ll know who is sending us spam and who is trying to hack into corporate networks. And when there are massive denial-of-service attacks, such as those against Estonia or Georgia or South Korea, we’ll know who was responsible and take action accordingly.
The problem is that it won’t work. Any design of the Internet must allow for anonymity. Universal identification is impossible. Even attribution—knowing who is responsible for particular Internet packets—is impossible. Attempting to build such a system is futile, and will only give criminals and hackers new ways to hide.
Imagine a magic world in which every Internet packet could be traced to its origin. Even in this world, our Internet security problems wouldn’t be solved. There’s a huge gap between proving that a packet came from a particular computer and that a packet was directed by a particular person. This is the exact problem we have with botnets, or pedophiles storing child porn on innocents’ computers. In these cases, we know the origins of the DDoS packets and the spam; they’re from legitimate machines that have been hacked. Attribution isn’t as valuable as you might think.
Implementing an Internet without anonymity is very difficult, and causes its own problems. In order to have perfect attribution, we’d need agencies—real-world organizations—to provide Internet identity credentials based on other identification systems: passports, national identity cards, driver’s licenses, whatever. Sloppier identification systems, based on things such as credit cards, are simply too easy to subvert. We have nothing that comes close to this global identification infrastructure. Moreover, centralizing information like this actually hurts security because it makes identity theft that much more profitable a crime.
And realistically, any theoretical ideal Internet would need to allow people access even without their magic credentials. People would still use the Internet at public kiosks and at friends’ houses. People would lose their magic Internet tokens just like they lose their driver’s licenses and passports today. The legitimate bypass mechanisms would allow even more ways for criminals and hackers to subvert the system.
On top of all this, the magic attribution technology doesn’t exist. Bits are bits; they don’t come with identity information attached to them. Every software system we’ve ever invented has been successfully hacked, repeatedly. We simply don’t have anywhere near the expertise to build an airtight attribution system.
Not that it really matters. Even if everyone could trace all packets perfectly, to the person or origin and not just the computer, anonymity would still be possible. It would just take one person to set up an anonymity server. If I wanted to send a packet anonymously to someone else, I’d just route it through that server. For even greater anonymity, I could route it through multiple servers. This is called onion routing and, with appropriate cryptography and enough users, it adds anonymity back to any communications system that prohibits it.
Attempts to banish anonymity from the Internet won’t affect those savvy enough to bypass it, would cost billions, and would have only a negligible effect on security. What such attempts would do is affect the average user’s access to free speech, including those who use the Internet’s anonymity to survive: dissidents in Iran, China, and elsewhere.
Mandating universal identity and attribution is the wrong goal. Accept that there will always be anonymous speech on the Internet. Accept that you’ll never truly know where a packet came from. Work on the problems you can solve: software that’s secure in the face of whatever packet it receives, identification systems that are secure enough in the face of the risks. We can do far better at these things than we’re doing, and they’ll do more to improve security than trying to fix insoluble problems.
The whole attribution problem is very similar to the copy-protection/digital-rights-management problem. Just as it’s impossible to make specific bits not copyable, it’s impossible to know where specific bits came from. Bits are bits. They don’t naturally come with restrictions on their use attached to them, and they don’t naturally come with author information attached to them. Any attempts to circumvent this limitation will fail, and will increasingly need to be backed up by the sort of real-world police-state measures that the entertainment industry is demanding in order to make copy-protection work. That’s how China does it: police, informants, and fear.
Just as the music industry needs to learn that the world of bits requires a different business model, law enforcement and others need to understand that the old ideas of identification don’t work on the Internet. For good or for bad, whether you like it or not, there’s always going to be anonymity on the Internet.
This essay originally appeared in Information Security, as part of a point/counterpoint with Marcus Ranum. You can read Marcus’s response below my essay.
EDITED TO ADD (2/5): Microsoft’s Craig Mundie wants to abolish anonymity as well.
What Mundie is proposing is to impose authentication. He draws an analogy to automobile use. If you want to drive a car, you have to have a license (not to mention an inspection, insurance, etc). If you do something bad with that car, like break a law, there is the chance that you will lose your license and be prevented from driving in the future. In other words, there is a legal and social process for imposing discipline. Mundie imagines three tiers of Internet ID: one for people, one for machines and one for programs (which often act as proxies for the other two).
Sidebar photo of Bruce Schneier by Joe MacInnis.