Optimal security limits of RFID distance bounding protocols

In this paper, we classify the RFID distance bounding protocols having bitwise fast phases and no final signature. We also give the theoretical security bounds for two specific classes, leaving the security bounds for the general case as an open problem. As for the classification, we introduce the notion of k-previous challenge dependent (k-PCD) protocols where each response bit depends on the current and k-previous challenges and there is no final signature. We treat the case k = 0, which means each response bit depends only on the current challenge, as a special case and define such protocols as current challenge dependent (CCD) protocols. In general, we construct a trade-off curve between the security levels of mafia and distance frauds by introducing two generic attack algorithms. This leads to the conclusion that CCD protocols cannot attain the ideal security against distance fraud, i.e. 1/2, for each challenge-response bit, without totally losing the security against mafia fraud. We extend the generic attacks to 1-PCD protocols and obtain a trade-off curve for 1-PCD protocols pointing out that 1-PCD protocols can provide better security than CCD protocols. Thereby, we propose a natural extension of a CCD protocol to a 1-PCD protocol in order to improve its security. As a study case, we give two natural extensions of Hancke and Kuhn protocol to show how to enhance the security against either mafia fraud or distance fraud without extra cost

A framework for analyzing RFID distance bounding protocols

Many distance bounding protocols appropriate for the RFID technology have been proposed recently. Unfortunately, they are commonly designed without any formal approach, which leads to inaccurate analyzes and unfair comparisons. Motivated by this need, we introduce a unied framework that aims to improve analysis and design of distance bounding protocols. Our framework includes a thorough terminology about the frauds, adversary, and prover, thus disambiguating many misleading terms. It also explores the adversary's capabilities and strategies, and addresses the impact of the prover's ability to tamper with his device. It thus introduces some new concepts in the distance bounding domain as the black-box and white-box models, and the relation between the frauds with respect to these models. The relevancy and impact of the framework is nally demonstrated on a study case: Munilla-Peinado distance bounding protocol

Highly Efficient and Re-executable Private Function Evaluation with Linear Complexity

The file attached to this record is the author's final peer reviewed version. The Publisher's final version can be found by following the DOI link.Private function evaluation aims to securely compute a function f(x1, ... ; xn) without leaking any information other than what is revealed by the output, where f is a private input of one of the parties (say Party1) and xi is a private input of the i-th party Partyi. In this work, we propose a novel and secure two-party private function evaluation (2PFE) scheme based on the DDH assumption. Our scheme introduces a reusability feature that signi cantly improves the state-of-the-art. Accordingly, our scheme has two variants, one is utilized in the initial execution of the function f, and the other is utilized in its subsequent evaluations. To the best of our knowledge, this is the first and most efficient 2PFE scheme that enjoys a reusablity feature. Our protocols achieve linear communication and computation complexities and a constant number of rounds which is at most three

Composition of Government Expenditure and Economic Growth in Ethiopia (1975-2011G.C)

The aim of this quantitative study is to analyze the compositions of public expenditure with economic growth in Ethiopia. The focuses of this paper is to examine which composition of public expenditure promoting economic growth in Ethiopia. Public expenditure data was collected from 1975-2011G.C. Regression analysis is applied to the composition of public expenditure on economic growth.  The study found that the independent variables (agri, he, rtac, trind,) altogether accounted 97 % changes in economic growth. On the other hand, considering the composition of public expenditure, on agriculture, health, trade and industry are statistically significant in explaining changes in economic growth. However, expenditure on road transport and communication is statically insignificant in explaining economic growth in Ethiopia. The study recommended that the government should increase efficiency of the financial resource by scrutinizing and evaluating for spending in transport and communication to create new capacity and support existing capacities. In addition, government should strengthen three principal-agent relationship dimensions(C=M+D – A) of the organizational structure that is crucial in decreasing the opportunity for corruption in government spending. From the social change perspective, if the government put into practice the suggested solutions as inputs for future policy formulation and successful execution of public expenditure, the wellbeing of the public will be enhanced. Ethiopians will experience significant improvements in growth and development, standard of livings and increase in employment. Keywords: Composition of public expenditure, economic growth, co-integration, unit root test

Hard congestion limit of the dissipative Aw-Rascle system with a polynomial offset function

We study the Aw-Rascle system in a one-dimensional domain with periodic boundary conditions, where the offset function is replaced by the gradient of the function $\rho_{n}^{\gamma}$, where $\gamma \to \infty$. The resulting system resembles the 1D pressureless compressible Navier-Stokes system with a vanishing viscosity coefficient in the momentum equation and can be used to model traffic and suspension flows. We first prove the existence of a unique global-in-time classical solution for $n$ fixed. Unlike the previous result for this system, we obtain global existence without needing to add any approximation terms to the system. This is by virtue of a $n-$uniform lower bound on the density which is attained by carrying out a maximum-principle argument on a suitable potential, $W_{n} = \rho_{n}^{-1}\partial_{x}w_{n}$. Then, we prove the convergence to a weak solution of a hybrid free-congested system as $n \to \infty$, which is known as the hard-congestion model