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Pek G.,Laboratory of Cryptography and System Security | Buttyan L.,Budapest University of Technology and Economics | Bencsath B.,Budapest University of Technology and Economics
ACM Computing Surveys | Year: 2013

Virtualization is a powerful technology for increasing the efficiency of computing services; however, besides its advantages, it also raises a number of security issues. In this article, we provide a thorough survey of those security issues in hardware virtualization. We focus on potential vulnerabilities and existing attacks on various virtualization platforms, but we also briefly sketch some possible countermeasures. To the best of our knowledge, this is the first survey of security issues in hardware virtualization with this level of details. Moreover, the adversary model and the structuring of the attack vectors are original contributions, never published before. © 2013 ACM.


Laszka A.,Laboratory of Cryptography and System Security | Foldes A.M.,Budapest University of Technology and Economics
Infocommunications Journal | Year: 2013

Recently, content-adaptive steganography was modeled by Johnson et al. as a stochastic, two-player, zero-sum game between a steganographer and a steganalyst [1]. To model economically rational steganalysts, we generalize this model by introducing a non-uniform cost of steganalysis. We characterize the Nash equilibria of our game based on the theory of blocking games [2], a class of quasi-zero-sum games, which were previously used to study the attack-resilience of systems and networks. Finally, we provide efficiently computable linear programs for finding an equilibrium. To the best of our knowledge, our paper is not only the first one to solve our generalized model, but it is also the first one to solve the original model for every possible combination of the parameter values.


Laszka A.,Laboratory of Cryptography and System Security | Gueye A.,U.S. National Institute of Standards and Technology
Performance Evaluation Review | Year: 2014

To design robust network topologies that resist strategic attacks, one must first be able to quantify robustness. In a recent line of research, the theory of network blocking games has been used to derive robustness metrics for topologies. However, these previous works did not consider the budget constraints of the network operator. In this paper, we introduce a budget limit on the operator and study two budget constraint formulations: the maximum and the expected cost constraints. For practical applications, the greatest challenge posed by blocking games is their computational complexity. Therefore, we show that the expected cost constraint formulation leads to games that can be solved efficiently, while the maximum cost constraint leads to NP-hard problems. As an illustrative example, this paper discusses the particular case of All-to-One (e.g., sensor or access) networks.


Buttyan L.,Laboratory of Cryptography and System Security | Grilo A.M.,University of Lisbon
IEEE International Conference on Communications | Year: 2011

We propose a secure distributed transport protocol for wireless sensor networks that resists against attacks on the reliability service provided by the protocol, as well as against energy depleting attacks. Our protocol is based on the Distributed Transport for Sensor Networks (DTSN) protocol, to which we add a security extension that consists in an efficient, symmetric key based authentication scheme for control packets. Besides describing the operation of our protocol, we also provide its analysis in terms of security and overhead. © 2011 IEEE.


Laszka A.,Laboratory of Cryptography and System Security | Gueye A.,U.S. National Institute of Standards and Technology
Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) | Year: 2013

Recently, network blocking game (NBG) models have been introduced and utilized to quantify the vulnerability of network topologies in adversarial environments. In NBG models, the payoff matrix of the game is only "implicitly " given. As a consequence, computing a Nash equilibrium in these games is expected to be harder than in more conventional models, where the payoff matrix is "explicitly " given. In this paper, we first show that computing a Nash equilibrium of a NBG is in general NP-hard. Surprisingly, however, there are particular interesting cases for which the game can be solved in polynomial time. We revisit these cases in a framework where the network is to be operated under budget constraints, which previous models did not consider. We generalize previous blocking games by introducing a budget limit on the operator and consider two constraint formulations: the maximum and the expected cost constraints. For practical applications, the greatest challenge posed by blocking games is their computational complexity. Therefore, we show that the maximum cost constraint leads to NP-hard problems, even for games that were shown to be efficiently solvable in the unconstrained case. On the other hand, we show that the expected cost constraint formulation leads to games that can be solved efficiently. © Springer International Publishing 2013.

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