Entries Tagged "academic papers"

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Research on Balancing Privacy with Surveillance

Interesting research: Michael Kearns, Aaron Roth, Zhiwei Steven Wu, and Grigory Yaroslavtsev, “Private algorithms for the protected in social network search,” PNAS, Jan 2016:

Abstract: Motivated by tensions between data privacy for individual citizens and societal priorities such as counterterrorism and the containment of infectious disease, we introduce a computational model that distinguishes between parties for whom privacy is explicitly protected, and those for whom it is not (the targeted subpopulation). The goal is the development of algorithms that can effectively identify and take action upon members of the targeted subpopulation in a way that minimally compromises the privacy of the protected, while simultaneously limiting the expense of distinguishing members of the two groups via costly mechanisms such as surveillance, background checks, or medical testing. Within this framework, we provide provably privacy-preserving algorithms for targeted search in social networks. These algorithms are natural variants of common graph search methods, and ensure privacy for the protected by the careful injection of noise in the prioritization of potential targets. We validate the utility of our algorithms with extensive computational experiments on two large-scale social network datasets.

Posted on February 24, 2016 at 6:05 AM • View Comments

Practical TEMPEST Attack

Four researchers have demonstrated a TEMPEST attack against a laptop, recovering its keys by listening to its electrical emanations. The cost for the attack hardware was about $3,000.

News article:

To test the hack, the researchers first sent the target a specific ciphertext—­in other words, an encrypted message.

“During the decryption of the chosen ciphertext, we measure the EM leakage of the target laptop, focusing on a narrow frequency band,” the paper reads. The signal is then processed, and “a clean trace is produced which reveals information about the operands used in the elliptic curve cryptography,” it continues, which in turn “is used in order to reveal the secret key.”

The equipment used included an antenna, amplifiers, a software-defined radio, and a laptop. This process was being carried out through a 15cm thick wall, reinforced with metal studs, according to the paper.

The researchers obtained the secret key after observing 66 decryption processes, each lasting around 0.05 seconds. “This yields a total measurement time of about 3.3 sec,” the paper reads. It’s important to note that when the researchers say that the secret key was obtained in “seconds,” that’s the total measurement time, and not necessarily how long it would take for the attack to actually be carried out. A real world attacker would still need to factor in other things, such as the target reliably decrypting the sent ciphertext, because observing that process is naturally required for the attack to be successful.

For half a century this has been a nation-state-level espionage technique. The cost is continually falling.

Posted on February 23, 2016 at 5:49 AM • View Comments

Determining Physical Location on the Internet

Interesting research: “CPV: Delay-based Location Verification for the Internet“:

Abstract: The number of location-aware services over the Internet continues growing. Some of these require the client’s geographic location for security-sensitive applications. Examples include location-aware authentication, location-aware access policies, fraud prevention, complying with media licensing, and regulating online gambling/voting. An adversary can evade existing geolocation techniques, e.g., by faking GPS coordinates or employing a non-local IP address through proxy and virtual private networks. We devise Client Presence Verification (CPV), a delay-based verification technique designed to verify an assertion about a device’s presence inside a prescribed geographic region. CPV does not identify devices by their IP addresses. Rather, the device’s location is corroborated in a novel way by leveraging geometric properties of triangles, which prevents an adversary from manipulating measured delays. To achieve high accuracy, CPV mitigates Internet path asymmetry using a novel method to deduce one-way application-layer delays to/from the client’s participating device, and mines these delays for evidence supporting/refuting the asserted location. We evaluate CPV through detailed experiments on PlanetLab, exploring various factors that affect its efficacy, including the granularity of the verified location, and the verification time. Results highlight the potential of CPV for practical adoption.

News articles.

Posted on February 12, 2016 at 6:19 AM • View Comments

Worldwide Encryption Products Survey

Today I released my worldwide survey of encryption products.

The findings of this survey identified 619 entities that sell encryption products. Of those 412, or two-thirds, are outside the U.S.-calling into question the efficacy of any US mandates forcing backdoors for law-enforcement access. It also showed that anyone who wants to avoid US surveillance has over 567 competing products to choose from. These foreign products offer a wide variety of secure applications­—voice encryption, text message encryption, file encryption, network-traffic encryption, anonymous currency­—providing the same levels of security as US products do today.

Details:

  • There are at least 865 hardware or software products incorporating encryption from 55 different countries. This includes 546 encryption products from outside the US, representing two-thirds of the total.
  • The most common non-US country for encryption products is Germany, with 112 products. This is followed by the United Kingdom, Canada, France, and Sweden, in that order.
  • The five most common countries for encryption products­—including the US­—account for two-thirds of the total. But smaller countries like Algeria, Argentina, Belize, the British Virgin Islands, Chile, Cyprus, Estonia, Iraq, Malaysia, St. Kitts and Nevis, Tanzania, and Thailand each produce at least one encryption product.
  • Of the 546 foreign encryption products we found, 56% are available for sale and 44% are free. 66% are proprietary, and 34% are open source. Some for-sale products also have a free version.
  • At least 587 entities­—primarily companies—­either sell or give away encryption products. Of those, 374, or about two-thirds, are outside the US.
  • Of the 546 foreign encryption products, 47 are file encryption products, 68 e-mail encryption products, 104 message encryption products, 35 voice encryption products, and 61 virtual private networking products.

The report is here, here, and here. The data, in Excel form, is here.

Press articles are starting to come in. (Here are the previous blog posts on the effort.)

I know the database is incomplete, and I know there are errors. I welcome both additions and corrections, and will be releasing a 1.1 version of this survey in a few weeks.

EDITED TO ADD (2/13): More news.

Posted on February 11, 2016 at 11:05 AM • View Comments

Tracking Anonymous Web Users

This research shows how to track e-commerce users better across multiple sessions, even when they do not provide unique identifiers such as user IDs or cookies.

Abstract: Targeting individual consumers has become a hallmark of direct and digital marketing, particularly as it has become easier to identify customers as they interact repeatedly with a company. However, across a wide variety of contexts and tracking technologies, companies find that customers can not be consistently identified which leads to a substantial fraction of anonymous visits in any CRM database. We develop a Bayesian imputation approach that allows us to probabilistically assign anonymous sessions to users, while ac- counting for a customer’s demographic information, frequency of interaction with the firm, and activities the customer engages in. Our approach simultaneously estimates a hierarchical model of customer behavior while probabilistically imputing which customers made the anonymous visits. We present both synthetic and real data studies that demonstrate our approach makes more accurate inference about individual customers’ preferences and responsiveness to marketing, relative to common approaches to anonymous visits: nearest- neighbor matching or ignoring the anonymous visits. We show how companies who use the proposed method will be better able to target individual customers, as well as infer how many of the anonymous visits are made by new customers.

Posted on February 5, 2016 at 6:56 AM • View Comments

Paper on the Going Dark Debate

I am pleased to have been a part of this report, part of the Berkman Center’s Berklett Cybersecurity project:

Don’t Panic: Making Progress on the “Going Dark” Debate

From the report:

In this report, we question whether the “going dark” metaphor accurately describes the state of affairs. Are we really headed to a future in which our ability to effectively surveil criminals and bad actors is impossible? We think not. The question we explore is the significance of this lack of access to communications for legitimate government interests. We argue that communications in the future will neither be eclipsed into darkness nor illuminated without shadow.

In short our findings are:

  • End-to-end encryption and other technological architectures for obscuring user data are unlikely to be adopted ubiquitously by companies, because the majority of businesses that provide communications services rely on access to user data for revenue streams and product functionality, including user data recovery should a password be forgotten.
  • Software ecosystems tend to be fragmented. In order for encryption to become both widespread and comprehensive, far more coordination and standardization than currently exists would be required.
  • Networked sensors and the Internet of Things are projected to grow substantially, and this has the potential to drastically change surveillance. The still images, video, and audio captured by these devices may enable real-time intercept and recording with after-the-fact access. Thus an inability to monitor an encrypted channel could be mitigated by the ability to monitor from afar a person through a different channel.
  • Metadata is not encrypted, and the vast majority is likely to remain so. This is data that needs to stay unencrypted in order for the systems to operate: location data from cell phones and other devices, telephone calling records, header information in e-mail, and so on. This information provides an enormous amount of surveillance data that was unavailable before these systems became widespread.
  • These trends raise novel questions about how we will protect individual privacy and security in the future. Today’s debate is important, but for all its efforts to take account of technological trends, it is largely taking place without reference to the full picture.

New York Times coverage. Lots more news coverage here. Slashdot thread. BoingBoing post.

EDITED TO ADD (2/8): Eleven news articles: one, two, three, four, five, six, seven, eight, nine, ten, and eleven.

Posted on February 2, 2016 at 2:20 PM • View Comments

Psychological Model of Selfishness

This is interesting:

Game theory decision-making is based entirely on reason, but humans don’t always behave rationally. David Rand, assistant professor of psychology, economics, cognitive science, and management at Yale University, and psychology doctoral student Adam Bear incorporated theories on intuition into their model, allowing agents to make a decision either based on instinct or rational deliberation.

In the model, there are multiple games of prisoners dilemma. But while some have the standard set-up, others introduce punishment for those who refuse to cooperate with a willing partner. Rand and Bear found that agents who went through many games with repercussions for selfishness became instinctively cooperative, though they could override their instinct to behave selfishly in cases where it made sense to do so.

However, those who became instinctively selfish were far less flexible. Even in situations where refusing to cooperate was punished, they would not then deliberate and rationally choose to cooperate instead.

The paper:

Abstract: Humans often cooperate with strangers, despite the costs involved. A long tradition of theoretical modeling has sought ultimate evolutionary explanations for this seemingly altruistic behavior. More recently, an entirely separate body of experimental work has begun to investigate cooperation’s proximate cognitive underpinnings using a dual-process framework: Is deliberative self-control necessary to reign in selfish impulses, or does self-interested deliberation restrain an intuitive desire to cooperate? Integrating these ultimate and proximate approaches, we introduce dual-process cognition into a formal game-theoretic model of the evolution of cooperation. Agents play prisoner’s dilemma games, some of which are one-shot and others of which involve reciprocity. They can either respond by using a generalized intuition, which is not sensitive to whether the game is one-shot or reciprocal, or pay a (stochastically varying) cost to deliberate and tailor their strategy to the type of game they are facing. We find that, depending on the level of reciprocity and assortment, selection favors one of two strategies: intuitive defectors who never deliberate, or dual-process agents who intuitively cooperate but sometimes use deliberation to defect in one-shot games. Critically, selection never favors agents who use deliberation to override selfish impulses: Deliberation only serves to undermine cooperation with strangers. Thus, by introducing a formal theoretical framework for exploring cooperation through a dual-process lens, we provide a clear answer regarding the role of deliberation in cooperation based on evolutionary modeling, help to organize a growing body of sometimes-conflicting empirical results, and shed light on the nature of human cognition and social decision making.

Very much in line with what I wrote in Liars and Outliers.

Posted on January 28, 2016 at 6:18 AM • View Comments

Security Trade-offs in the Longbow vs. Crossbow Decision

Interesting research: Douglas W. Allen and Peter T. Leeson, “Institutionally Constrained Technology Adoption: Resolving the Longbow Puzzle,” Journal of Law and Economics, v. 58, Aug 2015.

Abstract: For over a century the longbow reigned as undisputed king of medieval European missile weapons. Yet only England used the longbow as a mainstay in its military arsenal; France and Scotland clung to the technologically inferior crossbow. This longbow puzzle has perplexed historians for decades. We resolve it by developing a theory of institutionally constrained technology adoption. Unlike the crossbow, the longbow was cheap and easy to make and required rulers who adopted the weapon to train large numbers of citizens in its use. These features enabled usurping nobles whose rulers adopted the longbow to potentially organize effective rebellions against them. Rulers choosing between missile technologies thus confronted a trade-off with respect to internal and external security. England alone in late medieval Europe was sufficiently politically stable to allow its rulers the first-best technology option. In France and Scotland political instability prevailed, constraining rulers in these nations to the crossbow.

It’s nice to see my security interests intersect with my D&D interests.

Posted on January 22, 2016 at 6:44 AM • View Comments

De-Anonymizing Users from their Coding Styles

Interesting blog post:

We are able to de-anonymize executable binaries of 20 programmers with 96% correct classification accuracy. In the de-anonymization process, the machine learning classifier trains on 8 executable binaries for each programmer to generate numeric representations of their coding styles. Such a high accuracy with this small amount of training data has not been reached in previous attempts. After scaling up the approach by increasing the dataset size, we de-anonymize 600 programmers with 52% accuracy. There has been no previous attempt to de-anonymize such a large binary dataset. The abovementioned executable binaries are compiled without any compiler optimizations, which are options to make binaries smaller and faster while transforming the source code more than plain compilation. As a result, compiler optimizations further normalize authorial style. For the first time in programmer de-anonymization, we show that we can still identify programmers of optimized executable binaries. While we can de-anonymize 100 programmers from unoptimized executable binaries with 78% accuracy, we can de-anonymize them from optimized executable binaries with 64% accuracy. We also show that stripping and removing symbol information from the executable binaries reduces the accuracy to 66%, which is a surprisingly small drop. This suggests that coding style survives complicated transformations.

Here’s the paper.

And here’s their previous paper, de-anonymizing programmers from their source code.

Posted on January 4, 2016 at 7:41 AM • View Comments

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Sidebar photo of Bruce Schneier by Joe MacInnis.