5 resultados para DDOS ATTACKS

em WestminsterResearch - UK


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This paper proposes a technique to defeat Denial of Service (DoS) and Distributed Denial of Service (DDoS) attacks in Ad Hoc Networks. The technique is divided into two main parts and with game theory and cryptographic puzzles. Introduced first is a new client puzzle to prevent DoS attacks in such networks. The second part presents a multiplayer game that takes place between the nodes of an ad hoc network and based on fundamental principles of game theory. By combining computational problems with puzzles, improvement occurs in the efficiency and latency of the communicating nodes and resistance in DoS and DDoS attacks. Experimental results show the effectiveness of the approach for devices with limited resources and for environments like ad hoc networks where nodes must exchange information quickly.

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In this paper we propose a model for intelligent agents (sensors) on a Wireless Sensor Network to guard against energy-drain attacks in an energy-efficient and autonomous manner. This is intended to be achieved via an energy-harvested Wireless Sensor Network using a novel architecture to propagate knowledge to other sensors based on automated reasoning from an attacked sensor.

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In democratic polities, constitutional equilibria or balances of power between the executive and the legislature shift over time. Normative and empirical political theorists have long recognised that war, civil unrest, economic and political crises, terrorist attacks, and other events strengthen the power of the executive, disrupt and threaten constitutional politics, and damage democratic institutions: crises require swift action and executives are thought to be more capable than parliaments and legislatures of taking such actions. The terrorist attacks on New York and Washington on 11 September 2001 and the ensuing so-called 'war on terror' declared by President Bush clearly constituted a crisis, not only in the United States but also in other political systems, in part because of the US's hegemonic position in defining and shaping many other states' foreign and domestic policies. Dicey, Schmitt, and Rossiter suggest that critical events and political crises inevitably trigger the concentration of (emergency) powers in the hands of the executive. Aristotle and Machiavelli questioned the inevitability of this process. This article and the articles that follow in this Special Issue utilise empirical evidence, through the use of case studies of the United States, the United Kingdom, Russia, Australia, Israel, Italy and Indonesia, to address this debate. Specifically, the issue explores to what extent the external shock or crisis of 9/11 (and other terrorist attacks) and the ensuing 'war on terror' significantly changed the balance of executive-legislative relations from t (before the crisis) to t+1 (after the crisis) in these political systems, all of which were the targets of actual or foiled terrorist attacks. The most significant findings are that the shock of 9/11 and the 'war on terror' elicited varied responses by national executives and legislatures/parliaments and thus the balance of executive-legislative relations in different political systems; that, therefore, executive-legislative relations are positive rather than zero-sum; and that domestic political contexts conditioned these institutional responses.

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Congressional dominance theory holds that not only can the US Congress control the executive, it does. The terrorist attacks on New York and Washington on 11 September 2001 and the Bush administration's ensuing global 'war on terror' suggest a different result. Bush's response to 9/11 signalled not only new directions in US foreign and domestic policy but a new stage in the aggrandisement of presidential power in the United States and a further step in the marginalisation of the Congress. Informed by a constitutional doctrine unknown to the framers of the US Constitution, the Bush administration pursued a presidentialist or 'ultra-separationist' governing strategy that was disrespectful to the legislature's intended role in the separated system. Using its unilateral powers, in public and in secret, claiming 'inherent' authority from the Constitution, and exploiting the public's fear of a further terrorist attack and of endangering the lives of US troops abroad, the administration skilfully drove its legislation through the Congress. Occasionally, the Congress was able to extract concessions - notably in the immediate aftermath of 9/11, when partisan control of the government was split - but more typically, for most of the period, the Congress acquiesced to administration demands, albeit with the consolation of minor concessions. The administration not only dominated the lawmaking process, it also cowed legislators into legitimating often highly controversial (and sometimes illegal) administration-determined definitions of counter-terrorism and national security policy. Certainly, the Congress undertook a considerable amount of oversight during the period of the 'war on terror'; lawmakers also complained. But the effects on policy were marginal. This finding held true for periods of Democratic as well as Republican majorities.

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The infrastructure cloud (IaaS) service model offers improved resource flexibility and availability, where tenants - insulated from the minutiae of hardware maintenance - rent computing resources to deploy and operate complex systems. Large-scale services running on IaaS platforms demonstrate the viability of this model; nevertheless, many organizations operating on sensitive data avoid migrating operations to IaaS platforms due to security concerns. In this paper, we describe a framework for data and operation security in IaaS, consisting of protocols for a trusted launch of virtual machines and domain-based storage protection. We continue with an extensive theoretical analysis with proofs about protocol resistance against attacks in the defined threat model. The protocols allow trust to be established by remotely attesting host platform configuration prior to launching guest virtual machines and ensure confidentiality of data in remote storage, with encryption keys maintained outside of the IaaS domain. Presented experimental results demonstrate the validity and efficiency of the proposed protocols. The framework prototype was implemented on a test bed operating a public electronic health record system, showing that the proposed protocols can be integrated into existing cloud environments.