382 resultados para secure interoperation


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The disparity that exists between the highest and lowest achievers together with deficit approaches to teaching, learning and assessment raise serious equity issues related to fairness, validity, culture and access, which were analysed in a recent Australian Research Council funded project. This chapter explores the potential that exists for teachers to work with Indigenous Teacher Assistants (ITAs) to secure cultural connectedness in teaching, learning and assessment of Indigenous students. The study was a design experiment, which was conducted in seven Catholic and Independent primary schools in northern Queensland and involved semi-structured focus group interviews with Year 4 and 6 Indigenous students, principals, teachers and Indigenous Teacher Assistants. Classroom observations and document analyses were also conducted. This corpus of data was analysed using a sociocultural theoretical lens. The use of a sociocultural analysis helped to identify cultural influences, Indigenous students’ funds of knowledge and values. The information from this analysis was made explicit to teachers to demonstrate how they could enhance their pedagogic and assessment practices by embracing and extending the cultural spaces for learning and teaching of Indigenous students. The way in which teachers construct their interactions for greater cultural connectedness and enhanced learning would appear to rely on relationship building with Indigenous staff, Indigenous students’ cultural knowledge, and improved understanding of assessment and related equity issues.

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Identity-Based (IB) cryptography is a rapidly emerging approach to public-key cryptography that does not require principals to pre-compute key pairs and obtain certificates for their public keys— instead, public keys can be arbitrary identifiers such as email addresses, while private keys are derived at any time by a trusted private key generator upon request by the designated principals. Despite the flurry of recent results on IB encryption and signature, some questions regarding the security and efficiency of practicing IB encryption (IBE) and signature (IBS) as a joint IB signature/encryption (IBSE) scheme with a common set of parameters and keys, remain unanswered. We first propose a stringent security model for IBSE schemes. We require the usual strong security properties of: (for confidentiality) indistinguishability against adaptive chosen-ciphertext attacks, and (for nonrepudiation) existential unforgeability against chosen-message insider attacks. In addition, to ensure as strong as possible ciphertext armoring, we also ask (for anonymity) that authorship not be transmitted in the clear, and (for unlinkability) that it remain unverifiable by anyone except (for authentication) by the legitimate recipient alone. We then present an efficient IBSE construction, based on bilinear pairings, that satisfies all these security requirements, and yet is as compact as pairing-based IBE and IBS in isolation. Our scheme is secure, compact, fast and practical, offers detachable signatures, and supports multirecipient encryption with signature sharing for maximum scalability.

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This study investigates the development of teacher identity in a transnational context through an analysis of the voices of sixteen preservice teachers from Hong Kong who engage in interaction with primary students in an Australian classroom. The context for this research is the school-based experience undertaken by these preservice English as a second language teachers as part of their short language immersion (SLIM) program in Brisbane, Australia. Such SLIM programs are a genre of study abroad programs which have been gaining in popularity within teacher education in Australia, attended by preservice and inservice teachers from China, Hong Kong, Korea, and other Asian countries. This research is conducted at a time when the imperative to globalise higher education provision is a strategic factor in the educational policies of both Australia and Hong Kong. In Australia, international educational services now constitute the country’s third largest export with more than 400,000 students coming to Australia to study annually. In order to maintain Australia’s current global position as the third most popular Englishspeaking study destination, the government is now focusing on sustainability and the quality of the study experience being offered to international students (Bradley Review, 2008). In Hong Kong, the government sponsors both preservice and inservice English as a second language (ESL) teachers to undertake SLIM programs in Australia and other English-speaking countries, as part of their policy of promoting high levels of English proficiency in Hong Kong classrooms. Transnational teacher education is an important issue to which this study contributes insights into the affordances and constraints of a school-based experience in the transnational context. Second language teacher education has been defined as interventions designed to develop participants’ professional knowledge. In this study, it is argued that participation in a different community of practice helps to foreground tacit theories of second language pedagogy, making them visible and open to review. Questions of pedagogy are also seen as questions of teacher identity, constituting the way that one is in the classroom. I take up a sociocultural and poststructural framework, drawing on the work of James Gee and Mikhail Bakhtin, to theorise the construction of teacher identity as emerging through dialogic relations and socially situated discursive practices. From this perspective, this study investigates whether these teachers engage with different ways of representing themselves through appropriating, adapting or rejecting Discourses prevailing in the Australian classroom. Research suggests that reflecting on dilemmas encountered as lived experiences can extend professional understandings. In this study, the participants engage in a process of dialogic reflection on their intercultural classroom interactions, examining with their peers and their lecturer/researcher selected moments of dissonance that they have faced in the unfamiliar context of an Australian primary classroom. It is argued that the recursive and multivoiced nature of this process of reflection on practice allows participants opportunities to negotiate new understandings of second language teacher identity. Dialogic learning, based on the theories of Bakhtin and Vygotsky, provides the theoretic framing not only for the process of reflection instantiated in this study, but also features in the analysis of the participants’ second language classroom practices. The research design uses a combined discourse analytic and ethnographic approach as a logic-of-inquiry to explore the dialogic relationships which these second language teachers negotiate with their students and their peers in the transnational context. In this way, through discourse analysis of their classroom talk and reflective dialogues, assisted by the analytic tools of speech genres and discourse formats, I explore the participants’ ways of doing and being second language teachers. Thus, this analysis traces the process of ideological becoming of these beginner teachers as shifts in their understandings of teacher and student identities. This study also demonstrates the potential for a nontraditional stimulated recall interview to provide dialogic scaffolding for beginner teachers to reflect productively on their practice.

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Unless sustained, coordinated action is generated in road safety, road traffic deaths are poised to rise from approximately 1.3 to 1.9 million a year by 2020 (Krug, 2012). To generate this harmonised response, road safety management agencies are being urged to adopt multisectoral collaboration (WHO, 2009b), which is achievable through the principle of policy integration. Yet policy integration, in its current hierarchical format, is marred by a lack of universality of its interpretation, a failure to anticipate the complexities of coordinated effort, dearth of information about its design and the absence of a normative perspective to share responsibility. This paper addresses this ill-conception of policy integration by reconceptualising it through a qualitative examination of 16 road safety stakeholders’ written submissions, lodged with the Australian Transport Council in 2011. The resulting, new principle of policy integration, Participatory Deliberative Integration, provides a conceptual framework for the alignment of effort across stakeholders in transport, health, traffic law enforcement, relevant trades and the community. With the adoption of Participatory Deliberative Integration, road safety management agencies should secure the commitment of key stakeholders in the development and implementation of, amongst other policy measures, National Road Safety Strategies and Mix Mode Integrated Timetabling.

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International research on prisoners demonstrates poor health outcomes, including chronic disease, with the overall burden to the community high. Prisoners are predominantly male and young. In Australia, the average incarceration length is 3 years, sufficient to impact long term health, including nutrition. Food in prisons is highly controlled, yet gaps exist in policy. In most Western countries prisons promote healthy foods, often incongruent with prisoner expectations or wants. Few studies have been conducted on dietary intakes during incarceration in relation to food policy. In this study detailed diet histories were collected on 120/945 men (mean age = 32 years), in a high-secure prison. Intakes were verified via individual purchase records, mealtime observations, and audits of food preparation, purchasing and holdings. Physical measurements (including fasting bloods) were taken and medical records reviewed. Results showed the standard food provided consistent with current dietary guidelines, however limited in menu choice. Diet histories revealed self-funded foods contributing 1–63% of energy (mean = 30%), 0–83% sugar (mean = 38%), 1–77% saturated fats (mean = 31%) and 1–59% sodium (mean = 23%). High levels of modification to food provided was found using minimal cooking amenities and inclusion of self-funded foods and/or foods retained from previous meals. Medical records and physical measurements confirmed markers of chronic disease. This study highlights the need to establish clear guidelines on all food available in prisons if chronic disease risk reduction is a goal. This study has also supported evidenced based food and nutrition policy including menu choice, food quality, quantity and safety as well as type and access to self-funded foods.

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Background: Adolescent idiopathic scoliosis (AIS) is a deformity of the spine, which may 34 require surgical correction by attaching a rod to the patient’s spine using screws 35 implanted in the vertebral bodies. Surgeons achieve an intra-operative reduction in the 36 deformity by applying compressive forces across the intervertebral disc spaces while 37 they secure the rod to the vertebra. We were interested to understand how the 38 deformity correction is influenced by increasing magnitudes of surgical corrective forces 39 and what tissue level stresses are predicted at the vertebral endplates due to the 40 surgical correction. 41 Methods: Patient-specific finite element models of the osseoligamentous spine and 42 ribcage of eight AIS patients who underwent single rod anterior scoliosis surgery were 43 created using pre-operative computed tomography (CT) scans. The surgically altered 44 spine, including titanium rod and vertebral screws, was simulated. The models were 45 analysed using data for intra-operatively measured compressive forces – three load 46 profiles representing the mean and upper and lower standard deviation of this data 47 were analysed. Data for the clinically observed deformity correction (Cobb angle) were 48 compared with the model-predicted correction and the model results investigated to 49 better understand the influence of increased compressive forces on the biomechanics of 50 the instrumented joints. 51 Results: The predicted corrected Cobb angle for seven of the eight FE models were 52 within the 5° clinical Cobb measurement variability for at least one of the force profiles. 53 The largest portion of overall correction was predicted at or near the apical 54 intervertebral disc for all load profiles. Model predictions for four of the eight patients 55 showed endplate-to-endplate contact was occurring on adjacent endplates of one or 56 more intervertebral disc spaces in the instrumented curve following the surgical loading 57 steps. 58 Conclusion: This study demonstrated there is a direct relationship between intra-59 operative joint compressive forces and the degree of deformity correction achieved. The 60 majority of the deformity correction will occur at or in adjacent spinal levels to the apex 61 of the deformity. This study highlighted the importance of the intervertebral disc space 62 anatomy in governing the coronal plane deformity correction and the limit of this 63 correction will be when bone-to-bone contact of the opposing vertebral endplates 64 occurs.

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In the decision-making of multi-area ATC (Available Transfer Capacity) in electricity market environment, the existing resources of transmission network should be optimally dispatched and coordinately employed on the premise that the secure system operation is maintained and risk associated is controllable. The non-sequential Monte Carlo simulation is used to determine the ATC probability density distribution of specified areas under the influence of several uncertainty factors, based on which, a coordinated probabilistic optimal decision-making model with the maximal risk benefit as its objective is developed for multi-area ATC. The NSGA-II is applied to calculate the ATC of each area, which considers the risk cost caused by relevant uncertainty factors and the synchronous coordination among areas. The essential characteristics of the developed model and the employed algorithm are illustrated by the example of IEEE 118-bus test system. Simulative result shows that, the risk of multi-area ATC decision-making is influenced by the uncertainties in power system operation and the relative importance degrees of different areas.

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Predicate encryption (PE) is a new primitive which supports exible control over access to encrypted data. In PE schemes, users' decryption keys are associated with predicates f and ciphertexts encode attributes a that are specified during the encryption procedure. A user can successfully decrypt if and only if f(a) = 1. In this thesis, we will investigate several properties that are crucial to PE. We focus on expressiveness of PE, Revocable PE and Hierarchical PE (HPE) with forward security. For all proposed systems, we provide a security model and analysis using the widely accepted computational complexity approach. Our first contribution is to explore the expressiveness of PE. Existing PE supports a wide class of predicates such as conjunctions of equality, comparison and subset queries, disjunctions of equality queries, and more generally, arbitrary combinations of conjunctive and disjunctive equality queries. We advance PE to evaluate more expressive predicates, e.g., disjunctive comparison or disjunctive subset queries. Such expressiveness is achieved at the cost of computational and space overhead. To improve the performance, we appropriately revise the PE to reduce the computational and space cost. Furthermore, we propose a heuristic method to reduce disjunctions in the predicates. Our schemes are proved in the standard model. We then introduce the concept of Revocable Predicate Encryption (RPE), which extends the previous PE setting with revocation support: private keys can be used to decrypt an RPE ciphertext only if they match the decryption policy (defined via attributes encoded into the ciphertext and predicates associated with private keys) and were not revoked by the time the ciphertext was created. We propose two RPE schemes. Our first scheme, termed Attribute- Hiding RPE (AH-RPE), offers attribute-hiding, which is the standard PE property. Our second scheme, termed Full-Hiding RPE (FH-RPE), offers even stronger privacy guarantees, i.e., apart from possessing the Attribute-Hiding property, the scheme also ensures that no information about revoked users is leaked from a given ciphertext. The proposed schemes are also proved to be secure under well established assumptions in the standard model. Secrecy of decryption keys is an important pre-requisite for security of (H)PE and compromised private keys must be immediately replaced. The notion of Forward Security (FS) reduces damage from compromised keys by guaranteeing confidentiality of messages that were encrypted prior to the compromise event. We present the first Forward-Secure Hierarchical Predicate Encryption (FS-HPE) that is proved secure in the standard model. Our FS-HPE scheme offers some desirable properties: time-independent delegation of predicates (to support dynamic behavior for delegation of decrypting rights to new users), local update for users' private keys (i.e., no master authority needs to be contacted), forward security, and the scheme's encryption process does not require knowledge of predicates at any level including when those predicates join the hierarchy.

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Information Technology (IT) is successfully applied in a diverse range of fields. Though, the field of Medical Informatics is more than three decades old, it shows a very slow progress compared to many other fields in which the application of IT is growing rapidly. The spending on IT in health care is shooting up but the road to successful use of IT in health care has not been easy. This paper discusses about the barriers to the successful adoption of information technology in clinical environments and outlines the different approaches used by various countries and organisations to tackle the issues successfully. Investing financial and other resources to overcome the barriers for successful adoption of HIT is highly important to realise the dream of a future healthcare system with each customer having secure, private Electronic Health Record (EHR) that is available whenever and wherever needed, enabling the highest degree of coordinated medical care based on the latest medical knowledge and evidence. Arguably, the paper reviews barriers to HIT from organisations’ alignment in respect to the leadership; with their stated values when accepting or willingness to consider the HIT as a determinant factor on their decision-making processes. However, the review concludes that there are many aspects of the organisational accountability and readiness to agree to the technology implementation.

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Standardisation of validated communication protocols that aid in the adoption of policies, methods and tools in a secure eHealth setting require a significant cultural shift among clinicians

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Many software applications extend their functionality by dynamically loading executable components into their allocated address space. Such components, exemplified by browser plugins and other software add-ons, not only enable reusability, but also promote programming simplicity, as they reside in the same address space as their host application, supporting easy sharing of complex data structures and pointers. However, such components are also often of unknown provenance and quality and may be riddled with accidental bugs or, in some cases, deliberately malicious code. Statistics show that such component failures account for a high percentage of software crashes and vulnerabilities. Enabling isolation of such fine-grained components is therefore necessary to increase the stability, security and resilience of computer programs. This thesis addresses this issue by showing how host applications can create isolation domains for individual components, while preserving the benefits of a single address space, via a new architecture for software isolation called LibVM. Towards this end, we define a specification which outlines the functional requirements for LibVM, identify the conditions under which these functional requirements can be met, define an abstract Application Programming Interface (API) that encompasses the general problem of isolating shared libraries, thus separating policy from mechanism, and prove its practicality with two concrete implementations based on hardware virtualization and system call interpositioning, respectively. The results demonstrate that hardware isolation minimises the difficulties encountered with software based approaches, while also reducing the size of the trusted computing base, thus increasing confidence in the solution’s correctness. This thesis concludes that, not only is it feasible to create such isolation domains for individual components, but that it should also be a fundamental operating system supported abstraction, which would lead to more stable and secure applications.

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Authenticated Encryption (AE) is the cryptographic process of providing simultaneous confidentiality and integrity protection to messages. This approach is more efficient than applying a two-step process of providing confidentiality for a message by encrypting the message, and in a separate pass providing integrity protection by generating a Message Authentication Code (MAC). AE using symmetric ciphers can be provided by either stream ciphers with built in authentication mechanisms or block ciphers using appropriate modes of operation. However, stream ciphers have the potential for higher performance and smaller footprint in hardware and/or software than block ciphers. This property makes stream ciphers suitable for resource constrained environments, where storage and computational power are limited. There have been several recent stream cipher proposals that claim to provide AE. These ciphers can be analysed using existing techniques that consider confidentiality or integrity separately; however currently there is no existing framework for the analysis of AE stream ciphers that analyses these two properties simultaneously. This thesis introduces a novel framework for the analysis of AE using stream cipher algorithms. This thesis analyzes the mechanisms for providing confidentiality and for providing integrity in AE algorithms using stream ciphers. There is a greater emphasis on the analysis of the integrity mechanisms, as there is little in the public literature on this, in the context of authenticated encryption. The thesis has four main contributions as follows. The first contribution is the design of a framework that can be used to classify AE stream ciphers based on three characteristics. The first classification applies Bellare and Namprempre's work on the the order in which encryption and authentication processes take place. The second classification is based on the method used for accumulating the input message (either directly or indirectly) into the into the internal states of the cipher to generate a MAC. The third classification is based on whether the sequence that is used to provide encryption and authentication is generated using a single key and initial vector, or two keys and two initial vectors. The second contribution is the application of an existing algebraic method to analyse the confidentiality algorithms of two AE stream ciphers; namely SSS and ZUC. The algebraic method is based on considering the nonlinear filter (NLF) of these ciphers as a combiner with memory. This method enables us to construct equations for the NLF that relate the (inputs, outputs and memory of the combiner) to the output keystream. We show that both of these ciphers are secure from this type of algebraic attack. We conclude that using a keydependent SBox in the NLF twice, and using two different SBoxes in the NLF of ZUC, prevents this type of algebraic attack. The third contribution is a new general matrix based model for MAC generation where the input message is injected directly into the internal state. This model describes the accumulation process when the input message is injected directly into the internal state of a nonlinear filter generator. We show that three recently proposed AE stream ciphers can be considered as instances of this model; namely SSS, NLSv2 and SOBER-128. Our model is more general than a previous investigations into direct injection. Possible forgery attacks against this model are investigated. It is shown that using a nonlinear filter in the accumulation process of the input message when either the input message or the initial states of the register is unknown prevents forgery attacks based on collisions. The last contribution is a new general matrix based model for MAC generation where the input message is injected indirectly into the internal state. This model uses the input message as a controller to accumulate a keystream sequence into an accumulation register. We show that three current AE stream ciphers can be considered as instances of this model; namely ZUC, Grain-128a and Sfinks. We establish the conditions under which the model is susceptible to forgery and side-channel attacks.

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Availability has become a primary goal of information security and is as significant as other goals, in particular, confidentiality and integrity. Maintaining availability of essential services on the public Internet is an increasingly difficult task in the presence of sophisticated attackers. Attackers may abuse limited computational resources of a service provider and thus managing computational costs is a key strategy for achieving the goal of availability. In this thesis we focus on cryptographic approaches for managing computational costs, in particular computational effort. We focus on two cryptographic techniques: computational puzzles in cryptographic protocols and secure outsourcing of cryptographic computations. This thesis contributes to the area of cryptographic protocols in the following ways. First we propose the most efficient puzzle scheme based on modular exponentiations which, unlike previous schemes of the same type, involves only a few modular multiplications for solution verification; our scheme is provably secure. We then introduce a new efficient gradual authentication protocol by integrating a puzzle into a specific signature scheme. Our software implementation results for the new authentication protocol show that our approach is more efficient and effective than the traditional RSA signature-based one and improves the DoSresilience of Secure Socket Layer (SSL) protocol, the most widely used security protocol on the Internet. Our next contributions are related to capturing a specific property that enables secure outsourcing of cryptographic tasks in partial-decryption. We formally define the property of (non-trivial) public verifiability for general encryption schemes, key encapsulation mechanisms (KEMs), and hybrid encryption schemes, encompassing public-key, identity-based, and tag-based encryption avors. We show that some generic transformations and concrete constructions enjoy this property and then present a new public-key encryption (PKE) scheme having this property and proof of security under the standard assumptions. Finally, we combine puzzles with PKE schemes for enabling delayed decryption in applications such as e-auctions and e-voting. For this we first introduce the notion of effort-release PKE (ER-PKE), encompassing the well-known timedrelease encryption and encapsulated key escrow techniques. We then present a security model for ER-PKE and a generic construction of ER-PKE complying with our security notion.

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Denial-of-service (DoS) attacks are a growing concern to networked services like the Internet. In recent years, major Internet e-commerce and government sites have been disabled due to various DoS attacks. A common form of DoS attack is a resource depletion attack, in which an attacker tries to overload the server's resources, such as memory or computational power, rendering the server unable to service honest clients. A promising way to deal with this problem is for a defending server to identify and segregate malicious traffic as earlier as possible. Client puzzles, also known as proofs of work, have been shown to be a promising tool to thwart DoS attacks in network protocols, particularly in authentication protocols. In this thesis, we design efficient client puzzles and propose a stronger security model to analyse client puzzles. We revisit a few key establishment protocols to analyse their DoS resilient properties and strengthen them using existing and novel techniques. Our contributions in the thesis are manifold. We propose an efficient client puzzle that enjoys its security in the standard model under new computational assumptions. Assuming the presence of powerful DoS attackers, we find a weakness in the most recent security model proposed to analyse client puzzles and this study leads us to introduce a better security model for analysing client puzzles. We demonstrate the utility of our new security definitions by including two hash based stronger client puzzles. We also show that using stronger client puzzles any protocol can be converted into a provably secure DoS resilient key exchange protocol. In other contributions, we analyse DoS resilient properties of network protocols such as Just Fast Keying (JFK) and Transport Layer Security (TLS). In the JFK protocol, we identify a new DoS attack by applying Meadows' cost based framework to analyse DoS resilient properties. We also prove that the original security claim of JFK does not hold. Then we combine an existing technique to reduce the server cost and prove that the new variant of JFK achieves perfect forward secrecy (the property not achieved by original JFK protocol) and secure under the original security assumptions of JFK. Finally, we introduce a novel cost shifting technique which reduces the computation cost of the server significantly and employ the technique in the most important network protocol, TLS, to analyse the security of the resultant protocol. We also observe that the cost shifting technique can be incorporated in any Diffine{Hellman based key exchange protocol to reduce the Diffie{Hellman exponential cost of a party by one multiplication and one addition.

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This paper explores why some complaints of sexual harassment lodged under Australian anti-discrimination laws might settle during the conciliation process while others do not. It draws on an analysis of data collected from files of sexual harassment complaints lodged with all state, territory and federal human rights agencies in the area of employment over a six month period. The analysis suggests that complaints that conform with the stereotypical image of sexual harassment, where a woman is physically sexually harassed by a senior man, are more likely to settle as are complaints where the complainant is in full-time, secure employment and where complainants are not legally represented. However, sustained Australian research, including by human rights agencies, is vital is to further explore these issues.