736 resultados para security


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Choi et al. recently proposed an efficient RFID authentication protocol for a ubiquitous computing environment, OHLCAP(One-Way Hash based Low-Cost Authentication Protocol). However, this paper reveals that the protocol has several security weaknesses : 1) traceability based on the leakage of counter information, 2) vulnerability to an impersonation attack by maliciously updating a random number, and 3) traceability based on a physically-attacked tag. Finally, a security enhanced group-based authentication protocol is presented.

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Despite the conventional wisdom that proactive security is superior to reactive security, we show that reactive security can be competitive with proactive security as long as the reactive defender learns from past attacks instead of myopically overreacting to the last attack. Our game-theoretic model follows common practice in the security literature by making worst-case assumptions about the attacker: we grant the attacker complete knowledge of the defender’s strategy and do not require the attacker to act rationally. In this model, we bound the competitive ratio between a reactive defense algorithm (which is inspired by online learning theory) and the best fixed proactive defense. Additionally, we show that, unlike proactive defenses, this reactive strategy is robust to a lack of information about the attacker’s incentives and knowledge.

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Machine learning has become a valuable tool for detecting and preventing malicious activity. However, as more applications employ machine learning techniques in adversarial decision-making situations, increasingly powerful attacks become possible against machine learning systems. In this paper, we present three broad research directions towards the end of developing truly secure learning. First, we suggest that finding bounds on adversarial influence is important to understand the limits of what an attacker can and cannot do to a learning system. Second, we investigate the value of adversarial capabilities-the success of an attack depends largely on what types of information and influence the attacker has. Finally, we propose directions in technologies for secure learning and suggest lines of investigation into secure techniques for learning in adversarial environments. We intend this paper to foster discussion about the security of machine learning, and we believe that the research directions we propose represent the most important directions to pursue in the quest for secure learning.

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All organisations, irrespective of size and type, need effective information security management (ISM) practices to protect vital organisational in- formation assets. However, little is known about the information security management practices of nonprofit organisations. Australian nonprofit organisations (NPOs) employed 889,900 people, managed 4.6 million volunteers and contributed $40,959 million to the economy during 2006-2007 (Australian Bureau of Statistics, 2009). This thesis describes the perceptions of information security management in two Australian NPOs and examines the appropriateness of the ISO 27002 information security management standard in an NPO context. The overall approach to the research is interpretive. A collective case study has been performed, consisting of two instrumental case studies with the researcher being embedded within two NPOs for extended periods of time. Data gathering and analysis was informed by grounded theory and action research, and the Technology Acceptance Model was utilised as a lens to explore the findings and provide limited generalisability to other contexts. The major findings include a distinct lack of information security management best practice in both organisations. ISM Governance and risk management was lacking and ISM policy was either outdated or non- existent. While some user focused ISM practices were evident, reference to standards, such as ISO 27002, were absent. The main factor that negatively impacted on ISM practices was the lack of resources available for ISM in the NPOs studied. Two novel aspects of information security dis- covered in this research were the importance of accuracy and consistency of information. The contribution of this research is a preliminary understanding of ISM practices and perceptions in NPOs. Recommendations for a new approach to managing information security management in nonprofit organisations have been proposed.

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Defence organisations perform information security evaluations to confirm that electronic communications devices are safe to use in security-critical situations. Such evaluations include tracing all possible dataflow paths through the device, but this process is tedious and error-prone, so automated reachability analysis tools are needed to make security evaluations faster and more accurate. Previous research has produced a tool, SIFA, for dataflow analysis of basic digital circuitry, but it cannot analyse dataflow through microprocessors embedded within the circuit since this depends on the software they run. We have developed a static analysis tool that produces SIFA compatible dataflow graphs from embedded microcontroller programs written in C. In this paper we present a case study which shows how this new capability supports combined hardware and software dataflow analyses of a security critical communications device.

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Attachment difficulties have been proposed as a key risk factor for the development of alexithymia, a multifaceted personality trait characterised by difficulties identifying and describing feelings, a lack of imagination and an externally oriented thinking style. The present study investigated the relationship between attachment and alexithymia in an alcohol dependent population. Participants were 210 outpatients in a Cognitive Behavioural Treatment Program assessed on the Toronto Alexithymia Scale (TAS-20) and the Revised Adult Attachment Scale (RAAS). Significant relationships between anxious attachment and alexithymia factors were confirmed. Furthermore, alexithymic alcoholics reported significantly higher levels of anxious attachment and significantly lower levels of closeness (secure attachment) compared to non-alexithymic alcoholics. These findings highlight the importance of assessing and targeting anxious attachment among alexithymic alcoholics in order to improve alcohol treatment outcomes. Keywords: Attachment, alexithymia, alcohol dependence.

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With the rise in attacks and attempted attacks on marine‐based critical infrastructure, maritime security is an issue of increasing importance worldwide. However, there are three significant shortfalls in the efforts to overcome potential threats to maritime security: the need for greater understanding of whether current standards of best practice are truly successful in combating and reducing the risks of terrorism and other security issues, the absence of a collective maritime security best practice framework and the need for improved access to maritime security specific graduate and postgraduate (long) courses. This paper presents an overview of existing international, regional national standards of best practice and shows that literature concerning the measurement and/ or success of standards is virtually non‐existent. In addition, despite the importance of maritime workers to ensuring the safety of marine based critical infrastructure, a similar review of available Australian education courses shows a considerable lack of availability of maritime security‐specific courses other than short courses that cover only basic security matters. We argue that the absence of an Australian best practice framework informed by evaluation of current policy responses – particularly in the post 9/11 environment – leaves Australia vulnerable to maritime security threats. As this paper shows, the reality is that despite the security measures put in place post 9/11, there is still considerable work to be done to ensure Australia is equipped to overcome the threats posed to maritime security.

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Barreto-Lynn-Scott (BLS) curves are a stand-out candidate for implementing high-security pairings. This paper shows that particular choices of the pairing-friendly search parameter give rise to four subfami- lies of BLS curves, all of which offer highly efficient and implementation- friendly pairing instantiations. Curves from these particular subfamilies are defined over prime fields that support very efficient towering options for the full extension field. The coefficients for a specific curve and its correct twist are automat-ically determined without any computational effort. The choice of an extremely sparse search parameter is immediately reflected by a highly efficient optimal ate Miller loop and final exponentiation. As a resource for implementors, we give a list with examples of implementation-friendly BLS curves through several high-security levels.

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Power system dynamic analysis and security assessment are becoming more significant today due to increases in size and complexity from restructuring, emerging new uncertainties, integration of renewable energy sources, distributed generation, and micro grids. Precise modelling of all contributed elements/devices, understanding interactions in detail, and observing hidden dynamics using existing analysis tools/theorems are difficult, and even impossible. In this chapter, the power system is considered as a continuum and the propagated electomechanical waves initiated by faults and other random events are studied to provide a new scheme for stability investigation of a large dimensional system. For this purpose, the measured electrical indices (such as rotor angle and bus voltage) following a fault in different points among the network are used, and the behaviour of the propagated waves through the lines, nodes, and buses is analyzed. The impact of weak transmission links on a progressive electromechanical wave using energy function concept is addressed. It is also emphasized that determining severity of a disturbance/contingency accurately, without considering the related electromechanical waves, hidden dynamics, and their properties is not secure enough. Considering these phenomena takes heavy and time consuming calculation, which is not suitable for online stability assessment problems. However, using a continuum model for a power system reduces the burden of complex calculations