Information Leakage as a Model for Quality of Anonymity Networks

Measures for anonymity in systems must be on one hand simple and concise, and on the other hand reflect the realities of real systems. Such systems are heterogeneous, as are the ways they are used, the deployed anonymity measures, and finally the possible attack methods. Implementation quality and topologies of the anonymity measures must be considered as well. We therefore propose a new measure for the anonymity degree, that takes into account these various. We model the effectiveness of single mixes or of mix networks in terms of information leakage, and we measure it in terms of covert channel capacity. The relationship between the anonymity degree and information leakage is described, and an example is shown

Information Leakage as a Model for Quality of Anonymity Networks

Measures for anonymity in systems must be on one hand simple and concise, and on the other hand reflect the realities of real systems. Such systems are heterogeneous, as are the ways they are used, the deployed anonymity measures, and finally the possible attack methods. Implementation quality and topologies of the anonymity measures must be considered as well. We therefore propose a new measure for the anonymity degree, that takes into account these various. We model the effectiveness of single mixes or of mix networks in terms of information leakage, and we measure it in terms of covert channel capacity. The relationship between the anonymity degree and information leakage is described, and an example is shown

Organized Anonymous Agents

Anonymity can be of great importance in distributed agent applications such as e-commerce & auctions. This paper proposes and analyzes a new approach for organized anonymity of agents based on the use of pseudonyms. A novel naming scheme is presented that can be used by agent platforms to provide automatic anonymity for all agents on its platform, or, alternatively, to provide anonymity on demand. The paper also introduces a new technique, based on the use of handles, that can be fully integrated in an agent platform. Performance measures for an anonymity service implemented for the AgentScape platform provides some insight in the overhead involved. 1

A framework for automatically checking anonymity with μ CRL

We present a powerful and flexible method for automatically checking anonymity in a possibilistic general-purpose process algebraic verification toolset. We propose new definitions of a choice anonymity degree and a player anonymity degree, to quantify the precision with which an intruder is able to single out the true originator of a given event or to associate the right event to a given protocol participant. We show how these measures of anonymity can be automatically calculated from a protocol specification in µCRL, by using a combination of dedicated tools and existing state-of-the-art µCRL tools. To illustrate the flexibility of our method we test the Dining Cryptographers problem and the FOO 92 voting protocol. Our definitions of anonymity provide an accurate picture of the different ways that anonymity can break down, due for instance to coallitions of inside intruders. Our calculations can be performed on a cluster of machines, allowing us to check protocols for large numbers of participants

Removing the anonymity axiom in assessing pro-poor growth

The recent focus on ‘pro-poor growth’ led also to an intense debate on how exactly to define and to measure pro-poor growth. However, all suggested measures, irrespective whether they use the absolute or the relative definition of pro-poor growth have in common that they are based on the anonymity axiom, i.e. they do not distinguish between changes in horizontal and vertical inequality. That means usual assessments of pro-poor growth look at distributional changes over time and ignore how specific groups or households moved. Such a perspective may provide a very incomplete picture given that the common objective of most studies investigating the pro-poorness of growth is to test whether specific policy reforms where beneficial to the initially poor or not. Using panel data from Indonesia and Peru, this paper analyzes and illustrates empirically the implications of removing the anonymity axiom from measurements of pro-poor growth. It is shown that postulating anonymity, when assessing pro-poor growth can lead to misleading conclusions on how a specific policy affected the incomes of the initially poor. For both countries, the analysis shows substantial convergence to the mean, which is, at least for the case of Indonesia, robust to measurement error in the expenditure data.Anonymity axiom, pro-poor growth, income mobility, horizontal equity, inequality, decomposition

Enhanced anonymity in tax experiments does not affect compliance

In the domain of classical economic games, it has previously been suggested that deviations from purely rational behavior could be explained by a lack of experimenter-subject anonymity. In fact, some experiments show that contributions and prosocial behavior increase when participants feel observed. In the present study, we investigate whether measures of enhanced anonymity, beyond a conventional standard, are necessary in the particular case of tax behavior experiments. This issue might be pivotal for both the validity and generalizability of existing published studies as well as for designing future studies. We suspect social desirability to be even more relevant in experiments on tax compliance, which often apply a context-rich setting, entailing a strong ethical component. Interestingly, certain common experimental practices reflect potential breaches of anonymity during sign-up, the actual task, and the payment phase. Accordingly, we tested whether (1) tax compliance is higher under conditions of regular anonymity compared to enhanced anonymity, and (2) whether this anonymity manipulation moderates established effects of tax-related parameters, such as audit probability and fine rate. Despite an enhanced perception of anonymity due to our manipulation, we did not observe a difference in relative tax compliance between the regular and enhanced anonymity conditions. Additionally, enhanced anonymity did not interact with the effects of tax rate, audit probability, and fine level on tax compliance. We conclude that commonly used procedures in tax experiments are sufficient to guarantee a satisfactory level of anonymity

Standardization of guidelines for patient photograph deidentification

IMPORTANCE: This work was performed to advance patient care by protecting patient anonymity. OBJECTIVES: This study aimed to analyze the current practices used in patient facial photograph deidentification and set forth standardized guidelines for improving patient autonomy that are congruent with medical ethics and Health Insurance Portability and Accountability Act. DESIGN: The anonymization guidelines of 13 respected journals were reviewed for adequacy in accordance to facial recognition literature. Simple statistics were used to compare the usage of the most common concealment techniques in 8 medical journals which may publish the most facial photographs. SETTING: Not applicable. PARTICIPANTS: Not applicable. MAIN OUTCOME MEASURES: Facial photo deidentification guidelines of 13 journals were ascertained. Number and percentage of patient photographs lacking adequate anonymization in 8 journals were determined. RESULTS: Facial image anonymization guidelines varied across journals. When anonymization was attempted, 87% of the images were inadequately concealed. The most common technique used was masking the eyes alone with a black box. CONCLUSIONS: Most journals evaluated lack specific instructions for properly de-identifying facial photographs. The guidelines introduced here stress that both eyebrows and eyes must be concealed to ensure patient privacy. Examples of proper and inadequate photo anonymization techniques are provided. RELEVANCE: Improving patient care by ensuring greater patient anonymity

Website Proprietorship and Online Harassment

Although harassment and bullying have always existed, when such behavior is conducted online, the consequences can be uniquely devastating. The anonymity of harassers, the ease of widespread digital dissemination, and the inability to contain and/or eliminate online information can aggravate the nature of harassment on the Internet. Furthermore, section 230 of the Communications Decency Act provides Web site sponsors with immunity for content posted by others and no incentive to remove offending content. Given the unique nature of online harassment, ex post punitive measures are inadequate to redress grievances. In this Article, I propose the imposition of proprietorship liability upon Web site sponsors who fail to adopt reasonable measures to prevent foreseeable harm, such as online harassment. I also introduce several proposals to deter online harassment that would qualify as reasonable measures. These proposals incorporate contractual and architectural restraints, limits on anonymity, and restrictions on posting certain types of digital images