There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality.

Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

I and i

2 1 The innovative transport systems and the CityMobil project 10 1.1 The research questions 10 2 The state of art in the field of automatic transport systems 12 2.1 Case studies and demand studies for innovative transport systems 12 3 The design and implementation of surveys 14 3.1 Definition of experimental design 14 3.2 Questionnaire design and delivery 16 3.3 First analyses on the collected sample 18 4 Calibration of Logit Multionomial demand models 21 4.1 Methodology 21 4.2 Calibration of the “full” model. 22 4.3 Calibration of the “final” model 24 4.4 The demand analysis through the final Multinomial Logit model 25 5 The analysis of interaction between the demand and socioeconomic attributes 31 5.1 Methodology 31 5.2 Application of Mixed Logit models to the demand 31 5.3 Analysis of the interactions between demand and socioeconomic attributes through Mixed Logit models 32 5.4 Mixed Logit model and interaction between age and the demand for the CTS 38 5.5 Demand analysis with Mixed Logit model 39 6 Final analyses and conclusions 45 6.1 Comparison between the results of the analyses 45 6.2 Conclusions 48 6.3 Answers to the research questions and future developments 52

The European commission

We present Tor, a circuit-based low-latency anonymous communication service. This second-generation Onion Routing system addresses limitations in the original design by adding perfect forward secrecy, congestion control, directory servers, integrity checking, configurable exit policies, and a practical design for location-hidden services via rendezvous points. Tor works on the real-world Internet, requires no special privileges or kernel modifications, requires little synchronization or coordination between nodes, and provides a reasonable tradeoff between anonymity, usability, and efficiency. We briefly describe our experiences with an international network of more than 30 nodes. We close with a list of open problems in anonymous communication.

/pdf/tor-the-second-generation-onion-router-2qfrg0ppqb.pdf

Tor: the second-generation onion router

Social Network Analysis

National Institute of Standards and Technology における超伝導研究及び生活

The value attached to privacy has become a common notion in the press, featuring frequent stories of people selling sensitive personal information for a couple of dollars. Syverson argues [1] that we should incorporate the risk of data misuse into our reasoning about privacy valuations. Yet there are doubts as to whether people can, and do, value their privacy correctly and appropriately.

Privacy is a complex notion and as such it is very difficult to valuate it taking into account its full complexity. In this experiment we consider one aspect of privacy, namely location privacy, that can be compromised through mobile phone network data. We performed a European-wide study to assess the value that people attach to their location privacy using tools from experimental psychology and economics. We present the first results here.

The Value of Location Information

https://lirias.kuleuven.be/bitstream/123456789/353485/2/article-2179.pdf

Private Client-side Profiling with Random Forests and Hidden Markov Models

We study the effect compulsion attacks, through which an adversary can request a decryption or key from an honest node, have on the security of mix based anonymous communication systems Some specific countermeasures are proposed that increase the cost of compulsion attacks, detect that tracing is taking place and ultimately allow for some anonymity to be preserved even when all nodes are under compulsion Going beyond the case when a single message is traced, we also analyze the effect of multiple messages being traced and devise some techniques that could retain some anonymity Our analysis highlights that we can reason about plausible deniability in terms of the information theoretic anonymity metrics

/pdf/compulsion-resistant-anonymous-communications-54sh4lcdwp.pdf

Compulsion resistant anonymous communications

In recent years, there have been several proposals for anonymous communication systems that provide intentional weaknesses to allow anonymity to be circumvented in special cases. These anonymity revocation schemes attempt to retain the properties of strong anonymity systems while granting a special class of people the ability to selectively break through their protections. We evaluate the two dominant classes of anonymity revocation systems, and identify fundamental flaws in their architecture, leading to a failure to ensure proper anonymity revocation, as well as introducing additional weaknesses for users not targeted for anonymity revocation. © 2008 Springer-Verlag Berlin Heidelberg.

How to bypass two anonymity revocation schemes

Nowadays, service providers gather fine-grained data about users to deliver personalized services, for example, through the use of third-party cookies or social network profiles. This poses a threat both to privacy, since the amount of information obtained is excessive for the purpose of customization, and authenticity, because those methods employed to gather data can be blocked and fooled.

In this paper we propose privacy-preserving profiling techniques, in which users perform the profiling task locally, reveal to service providers the result and prove its correctness. We address how our approach applies to tasks of both classification and pattern recognition. For the former, we describe client-side profiling based on random forests, where users, based on certified input data representing their activity, resolve a random forest and reveal the classification result to service providers. For the latter, we show how to match a stream of user activity to a regular expression, or how to assign it a probability using a hidden Markov model. Our techniques, based on the use of zero-knowledge proofs, can be composed with other protocols as part of the certification of a larger computation.

/pdf/private-client-side-profiling-with-random-forests-and-hidden-4oe7c10lqo.pdf

George Danezis

Papers

The Value of Location Information

Private Client-side Profiling with Random Forests and Hidden Markov Models

Compulsion resistant anonymous communications

How to bypass two anonymity revocation schemes

Private client-side profiling with random forests and hidden markov models