scholarly journals (∈, δ)-Indistinguishable Mixing for Cryptocurrencies

2021 ◽  
Vol 2022 (1) ◽  
pp. 49-74
Author(s):  
Mingyu Liang ◽  
Ioanna Karantaidou ◽  
Foteini Baldimtsi ◽  
S. Dov Gordon ◽  
Mayank Varia
Keyword(s):  
Theoretical Approach ◽  
Differential Privacy ◽  
Computation Time ◽  
Ring Signatures ◽  
Mixing Schemes ◽  
Definition Of

Abstract We propose a new theoretical approach for building anonymous mixing mechanisms for cryptocurrencies. Rather than requiring a fully uniform permutation during mixing, we relax the requirement, insisting only that neighboring permutations are similarly likely. This is defined formally by borrowing from the definition of differential privacy. This relaxed privacy definition allows us to greatly reduce the amount of interaction and computation in the mixing protocol. Our construction achieves O(n·polylog(n)) computation time for mixing n addresses, whereas all other mixing schemes require O(n 2) total computation across all parties. Additionally, we support a smooth tolerance of fail-stop adversaries and do not require any trusted setup. We analyze the security of our generic protocol under the UC framework, and under a stand-alone, game-based definition. We finally describe an instantiation using ring signatures and confidential transactions.

scholarly journals Theoretical approach of the international business environment

2021 ◽  
Author(s):  
Nicolae Țău ◽  
◽  
Ibrahim Mustafa Sharfeldin Mohammedelkhatim ◽  
Keyword(s):  
International Business ◽  
Theoretical Approach ◽  
Business Environment ◽  
Large Field ◽  
Huge Number ◽  
Knowledge And Skills ◽  
Goods And Services ◽  
National Boundaries ◽  
Definition Of

The definition of international business is related to commercial transactions that occur across country borders. The exchange of goods and services among peoples and businesses is organized between multiple countries. The term is composed of two words; International has many meanings, among them external and global. The word Business has also various senses such as trade, transaction and commercial relations. This huge number of words and concepts describes the large field of affairs. International business means the exchange of goods, services, resources, knowledge and skills among other things between two or more firms and/ or countries. It can also denote the trade conducted across national boundaries for the profit of all parties connected on an industry. It refers to negotiated commerce and investment performed by firms across boarders functioning together at several levels.

scholarly journals Differential Privacy for Statistics: What we Know and What we Want to Learn

2010 ◽  
Vol 1 (2) ◽  
Author(s):  
Cynthia Dwork ◽  
Adam Smith
Keyword(s):  
Research Agenda ◽  
Data Privacy ◽  
Differential Privacy ◽  
Definition Of

We motivate and review the definition of differential privacy, survey some results on differentially private statistical estimators, and outline a research agenda. This survey is based on two presentations given by the authors at an NCHS/CDC sponsored workshop on data privacy in May 2008.

Contemporary Terrorist Challenges and Threats in Europe

2021 ◽  
Vol 38 (38) ◽  
pp. 122-137
Author(s):  
Darko Trifunovic ◽  
Juliusz Piwowarski
Keyword(s):  
Significant Role ◽  
Theoretical Approach ◽  
Essential Elements ◽  
International Terrorism ◽  
The Internet ◽  
Security Threats ◽  
Unique Definition ◽  
Use Of The Internet ◽  
Definition Of ◽  
Security Science

This article generally contains two parts. One is a theoretical approach to dealing with the phenomenon of terrorism as well as international terrorism. Within the first part, a unique definition of the concept of security science is given, without which it is not possible to properly perceive or investigate security threats and risks within which terrorism is one of the significant threats. The second part deals with models of terrorist activities with special attention to the webspace and the significant role that terrorists attach to the increasing use of the Internet for their purposes. The theoretical part leads to the conclusion that there are five essential elements whose presence, if detected in one territory or state, indicates the existence of a mechanism that produces or creates new jihad warriors. The paper also gives a unique forecast of the degree of endangerment on the example of a territory, which gives scientists who investigate these threats a new direction of research.

scholarly journals Privacy-Preserving Monotonicity of Differential Privacy Mechanisms

2018 ◽  
Vol 8 (11) ◽  
pp. 2081 ◽  
Author(s):  
Hai Liu ◽  
Zhenqiang Wu ◽  
Yihui Zhou ◽  
Changgen Peng ◽  
Feng Tian ◽  
...  
Keyword(s):  
Differential Privacy ◽  
Estimation Error ◽  
Privacy Preserving ◽  
Randomized Response ◽  
Response Mechanism ◽  
Rational Model ◽  
Trade Off ◽  
Definition Of ◽  
Utility Metrics ◽  
Monotonicity Results

Differential privacy mechanisms can offer a trade-off between privacy and utility by using privacy metrics and utility metrics. The trade-off of differential privacy shows that one thing increases and another decreases in terms of privacy metrics and utility metrics. However, there is no unified trade-off measurement of differential privacy mechanisms. To this end, we proposed the definition of privacy-preserving monotonicity of differential privacy, which measured the trade-off between privacy and utility. First, to formulate the trade-off, we presented the definition of privacy-preserving monotonicity based on computational indistinguishability. Second, building on privacy metrics of the expected estimation error and entropy, we theoretically and numerically showed privacy-preserving monotonicity of Laplace mechanism, Gaussian mechanism, exponential mechanism, and randomized response mechanism. In addition, we also theoretically and numerically analyzed the utility monotonicity of these several differential privacy mechanisms based on utility metrics of modulus of characteristic function and variant of normalized entropy. Third, according to the privacy-preserving monotonicity of differential privacy, we presented a method to seek trade-off under a semi-honest model and analyzed a unilateral trade-off under a rational model. Therefore, privacy-preserving monotonicity can be used as a criterion to evaluate the trade-off between privacy and utility in differential privacy mechanisms under the semi-honest model. However, privacy-preserving monotonicity results in a unilateral trade-off of the rational model, which can lead to severe consequences.

A “Global Theory of Federalism”: The Nature and Challenges of a Federal State

2005 ◽  
Vol 6 (10) ◽  
pp. 1297-1318 ◽  
Author(s):  
Anna Gamper
Keyword(s):  
Theoretical Approach ◽  
Constitutional Law ◽  
Federal State ◽  
Common Denominator ◽  
Global Theory ◽  
Theoretical Approaches ◽  
Interdisciplinary Character ◽  
Or Economics ◽  
Definition Of ◽  
Concrete Concept

Innumerable attempts have been made to explore the theoretical nature of federalism. Due to the long history, worldwide existence and interdisciplinary character of federalism, a plethora of literature has been written on the topic. Yet, these endeavours have not even resulted in a clear and commonly used definition of the term. Surely, it is one of the great dilemmas of this field of research that despite so much discussion, there is no settled common denominator of ‘federalism'. Whereas practical studies and exchange of experience between the various federal systems offer a more conventional research arena, comparative theoretical approaches are much more seldom. This is not the least because of the tremendous semantic challenges of a comparative theoretical approach. At first glance, it is sometimes difficult to understand the terminology of federalism, the meaning of which differs according to the perspectives of constitutional law, political science or economics. Even more difficulty arises when the substance of federal theories is discussed. Again, differences between theories may be due to different academic approaches, particularly between understanding federalism as an overall principle or as a more concrete concept of a federal state and, in particular, whether the constituent units of a federal state are states, and, if states, whether they are sovereign.

scholarly journals Privacy-Preserving Data Sharing for Genome-Wide Association Studies

2013 ◽  
Vol 5 (1) ◽  
Author(s):  
Caroline Uhler ◽  
Aleksandra B. Slavkovic ◽  
Stephen E. Fienberg
Keyword(s):  
Differential Privacy ◽  
Association Studies ◽  
Simulated Data ◽  
Privacy Preserving ◽  
External Information ◽  
Genome Wide Association Studies ◽  
Chi Square ◽  
Gwas Study ◽  
Genome Wide ◽  
Definition Of

Traditional statistical methods for confidentiality protection of statistical databases do not scale well to deal with GWAS databases especially in terms of guarantees regarding protection from linkage to external information. The more recent concept of differential privacy, introduced by the cryptographic community, is an approach which provides a rigorous definition of privacy with meaningful privacy guarantees in the presence of arbitrary external information, although the guarantees may come at a serious price in terms of data utility. Building on such notions, we propose new methods to release aggregate GWAS data without compromising an individual’s privacy. We present methods for releasing differentially private minor allele frequencies, chi-square statistics and p-values. We compare these approaches on simulated data and on a GWAS study of canine hair length involving 685 dogs. We also propose a privacy-preserving method for finding genome-wide associations based on a differentially-private approach to penalized logistic regression.

scholarly journals Calibrating Noise to Sensitivity in Private Data Analysis

2017 ◽  
Vol 7 (3) ◽  
pp. 17-51 ◽  
Author(s):  
Cynthia Dwork ◽  
Frank McSherry ◽  
Kobbi Nissim ◽  
Adam Smith
Keyword(s):  
Standard Deviation ◽  
Differential Privacy ◽  
Random Noise ◽  
Sensitive Information ◽  
Private Data ◽  
Single Argument ◽  
True Answer ◽  
Definition Of ◽  
Analytical Tools ◽  
Separation Results

We continue a line of research initiated in Dinur and Nissim (2003); Dwork and Nissim (2004); and Blum et al. (2005) on privacy-preserving statistical databases. Consider a trusted server that holds a database of sensitive information. Given a query function $f$ mapping databases to reals, the so-called {\em true answer} is the result of applying $f$ to the database. To protect privacy, the true answer is perturbed by the addition of random noise generated according to a carefully chosen distribution, and this response, the true answer plus noise, is returned to the user. Previous work focused on the case of noisy sums, in which $f = \sum_i g(x_i)$, where $x_i$ denotes the $i$th row of the database and $g$ maps database rows to $[0,1]$. We extend the study to general functions $f$, proving that privacy can be preserved by calibrating the standard deviation of the noise according to the {\em sensitivity} of the function $f$. Roughly speaking, this is the amount that any single argument to $f$ can change its output. The new analysis shows that for several particular applications substantially less noise is needed than was previously understood to be the case. The first step is a very clean definition of privacy---now known as differential privacy---and measure of its loss. We also provide a set of tools for designing and combining differentially private algorithms, permitting the construction of complex differentially private analytical tools from simple differentially private primitives. Finally, we obtain separation results showing the increased value of interactive statistical release mechanisms over non-interactive ones.

scholarly journals Special Issue on the Theory and Practice of Differential Privacy

2017 ◽  
Vol 7 (2) ◽  
Author(s):  
Marco Gaboardi ◽  
Chris J. Skinner
Keyword(s):  
Data Analysis ◽  
Programming Languages ◽  
Differential Privacy ◽  
International Workshop ◽  
Theory And Practice ◽  
Release Mechanism ◽  
Special Issue ◽  
Research Areas ◽  
Recent Developments ◽  
Definition Of

This special issue presents papers based on contributions to the first international workshop on the “Theory and Practice of Differential Privacy” (TPDP) held in London, UK, 18 April 2015, as part of the European joint conference on Theory And Practice of Software (ETAPS). Differential privacy is a mathematically rigorous definition of the privacy protection provided by a data release mechanism: it offers a strong guaranteed bound on what can be learned about a user as a result of participating in a differentially private data analysis. Researchers in differential privacy come from several areas of computer science, including algorithms, programming languages, security, databases and machine learning, as well as from several areas of statistics and data analysis. The workshop was intended to be an occasion for researchers from these different research areas to discuss the recent developments in the theory and practice of differential privacy. The program of the workshop included 10 contributed talks, 1 invited speaker and 1 joint invited speaker with the workshop “Hot Issues in Security Principles and Trust” (HotSpot 2016). Participants at the workshop were invited to submit papers to this special issue. Six papers were accepted, most of which directly reflect talks presented at the workshop

scholarly journals AnoA: A Framework for Analyzing Anonymous Communication Protocols

2017 ◽  
Vol 7 (2) ◽  
Author(s):  
Michael Backes ◽  
Aniket Kate ◽  
Praveen Manoharan ◽  
Sebastian Meiser ◽  
Esfandiar Mohammadi
Keyword(s):  
Quantitative Analysis ◽  
Complex Systems ◽  
Differential Privacy ◽  
The Internet ◽  
Anonymous Communication ◽  
Universal Composability ◽  
Multiplicative Factor ◽  
Generic Framework ◽  
The Subject ◽  
Definition Of

Anonymous communication (AC) protocols such as the widely used Tor network have been designed to provide anonymity over the Internet to their participating users. While AC protocols have been the subject of several security and anonymity analyses in the last years, there still does not exist a framework for analyzing these complex systems and their different anonymity properties in a unified manner.   In this work we present AnoA: a generic framework for defining, analyzing, and quantifying anonymity properties for AC protocols. In addition to quantifying the (additive) advantage of an adversary in an indistinguishability-based definition, AnoA uses a multiplicative factor, inspired from differential privacy. AnoA enables a unified quantitative analysis of well-established anonymity properties, such as sender anonymity, sender unlinkability, and relationship anonymity. AnoA modularly specifies adversarial capabilities by a simple wrapper-construction, called adversary classes. We examine the structure of these adversary classes and identify conditions under which it suffices to establish anonymity guarantees for single messages in order to derive guarantees for arbitrarily many messages. This then leads us to the definition of Plug’n’Play adversary classes (PAC), which are easy-to-use, expressive, and satisfy this condition. We prove that our framework is compatible with the universal composability (UC) framework and show how to apply AnoA to a simplified version of Tor against passive adversaries, leveraging a recent realization proof in the UC framework.

scholarly journals On the 'Semantics' of Differential Privacy: A Bayesian Formulation

2014 ◽  
Vol 6 (1) ◽  
Author(s):  
Shiva P. Kasiviswanathan ◽  
Adam Smith
Keyword(s):  
Differential Privacy ◽  
Side Information ◽  
Precise Formulation ◽  
Statistical Databases ◽  
Bayesian Formulation ◽  
Definition Of

Differential privacy is a definition of privacy for algorithms that analyze and publish information about statistical databases. It is often claimed that differential privacy provides guarantees against adversaries with arbitrary side information. In this paper, we provide a precise formulation of these guarantees in terms of the inferences drawn by a Bayesian adversary. We show that this formulation is satisfied by both epsilon-differential privacy as well as a relaxation known as (epsilon,delta)-differential privacy. Our formulation follows the ideas originally due to Dwork and McSherry. This paper is, to our knowledge, the first place such a formulation appears explicitly. The analysis of the relaxed definition is new to this paper, and provides some guidance for setting the delta parameter when using (epsilon,delta)-differential privacy.

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