Cryptographic Randomized Response Techniques

We develop cryptographically secure techniques to guarantee unconditional privacy for respondents to polls. Our constructions are efficient and practical, and are shown not to allow cheating respondents to affect the ``tally'' by more than their own vote -- which will be given the exact same weight as that of other respondents. We demonstrate solutions to this problem based on both traditional cryptographic techniques and quantum cryptography.Comment: 21 page

Differential Privacy - A Balancing Act

Data privacy is an ever important aspect of data analyses. Historically, a plethora of privacy techniques have been introduced to protect data, but few have stood the test of time. From investigating the overlap between big data research, and security and privacy research, I have found that differential privacy presents itself as a promising defender of data privacy.Differential privacy is a rigorous, mathematical notion of privacy. Nevertheless, privacy comes at a cost. In order to achieve differential privacy, we need to introduce some form of inaccuracy (i.e. error) to our analyses. Hence, practitioners need to engage in a balancing act between accuracy and privacy when adopting differential privacy. As a consequence, understanding this accuracy/privacy trade-off is vital to being able to use differential privacy in real data analyses.In this thesis, I aim to bridge the gap between differential privacy in theory, and differential privacy in practice. Most notably, I aim to convey a better understanding of the accuracy/privacy trade-off, by 1) implementing tools to tweak accuracy/privacy in a real use case, 2) presenting a methodology for empirically predicting error, and 3) systematizing and analyzing known accuracy improvement techniques for differentially private algorithms. Additionally, I also put differential privacy into context by investigating how it can be applied in the automotive domain. Using the automotive domain as an example, I introduce the main challenges that constitutes the balancing act, and provide advice for moving forward

Privacy preserving data publishing with multiple sensitive attributes

Data mining is the process of extracting hidden predictive information from large databases, it has a great potential to help governments, researchers and companies focus on the most significant information in their data warehouses. High quality data and effective data publishing are needed to gain a high impact from data mining process. However there is a clear need to preserve individual privacy in the released data. Privacy-preserving data publishing is a research topic of eliminating privacy threats. At the same time it provides useful information in the released data. Normally datasets include many sensitive attributes; it may contain static data or dynamic data. Datasets may need to publish multiple updated releases with different time stamps. As a concrete example, public opinions include highly sensitive information about an individual and may reflect a person's perspective, understanding, particular feelings, way of life, and desires. On one hand, public opinion is often collected through a central server which keeps a user profile for each participant and needs to publish this data for researchers to deeply analyze. On the other hand, new privacy concerns arise and user's privacy can be at risk. The user's opinion is sensitive information and it must be protected before and after data publishing. Opinions are about a few issues, while the total number of issues is huge. In this case we will deal with multiple sensitive attributes in order to develop an efficient model. Furthermore, opinions are gathered and published periodically, correlations between sensitive attributes in different releases may occur. Thus the anonymization technique must care about previous releases as well as the dependencies between released issues. This dissertation identifies a new privacy problem of public opinions. In addition it presents two probabilistic anonymization algorithms based on the concepts of k-anonymity [1, 2] and l-diversity [3, 4] to solve the problem of both publishing datasets with multiple sensitive attributes and publishing dynamic datasets. Proposed algorithms provide a heuristic solution for multidimensional quasi-identifier and multidimensional sensitive attributes using probabilistic l-diverse definition. Experimental results show that these algorithms clearly outperform the existing algorithms in term of anonymization accuracy

From Social Data Mining to Forecasting Socio-Economic Crisis

Socio-economic data mining has a great potential in terms of gaining a better understanding of problems that our economy and society are facing, such as financial instability, shortages of resources, or conflicts. Without large-scale data mining, progress in these areas seems hard or impossible. Therefore, a suitable, distributed data mining infrastructure and research centers should be built in Europe. It also appears appropriate to build a network of Crisis Observatories. They can be imagined as laboratories devoted to the gathering and processing of enormous volumes of data on both natural systems such as the Earth and its ecosystem, as well as on human techno-socio-economic systems, so as to gain early warnings of impending events. Reality mining provides the chance to adapt more quickly and more accurately to changing situations. Further opportunities arise by individually customized services, which however should be provided in a privacy-respecting way. This requires the development of novel ICT (such as a self- organizing Web), but most likely new legal regulations and suitable institutions as well. As long as such regulations are lacking on a world-wide scale, it is in the public interest that scientists explore what can be done with the huge data available. Big data do have the potential to change or even threaten democratic societies. The same applies to sudden and large-scale failures of ICT systems. Therefore, dealing with data must be done with a large degree of responsibility and care. Self-interests of individuals, companies or institutions have limits, where the public interest is affected, and public interest is not a sufficient justification to violate human rights of individuals. Privacy is a high good, as confidentiality is, and damaging it would have serious side effects for society.Comment: 65 pages, 1 figure, Visioneer White Paper, see http://www.visioneer.ethz.c

Curtailment of Early Election Predictions: Can We Predict the Outcome?

This note analyzes the constitutional ramifications of legislative attempts to restrict early election predictions. First, specific congressional proposals and state legislative enactments will be examined. Secondly, the various standards of review the Supreme Court applies when government regulation threatens to infringe upon first amendment free speech will be examined. Lastly, this paper will examine the competing interests involved in early election predictions and will conclude that limitations on this process would be an unconstitutional impairment of the public\u27s first amendment rights