205 resultados para Leonie Reygers
Resumo:
Nonlinear filter generators are common components used in the keystream generators for stream ciphers and more recently for authentication mechanisms. They consist of a Linear Feedback Shift Register (LFSR) and a nonlinear Boolean function to mask the linearity of the LFSR output. Properties of the output of a nonlinear filter are not well studied. Anderson noted that the m-tuple output of a nonlinear filter with consecutive taps to the filter function is unevenly distributed. Current designs use taps which are not consecutive. We examine m-tuple outputs from nonlinear filter generators constructed using various LFSRs and Boolean functions for both consecutive and uneven (full positive difference sets where possible) tap positions. The investigation reveals that in both cases, the m-tuple output is not uniform. However, consecutive tap positions result in a more biased distribution than uneven tap positions, with some m-tuples not occurring at all. These biased distributions indicate a potential flaw that could be exploited for cryptanalysis
Resumo:
This work examines the algebraic cryptanalysis of small scale variants of the LEX-BES. LEX-BES is a stream cipher based on the Advanced Encryption Standard (AES) block cipher. LEX is a generic method proposed for constructing a stream cipher from a block cipher, initially introduced by Biryukov at eSTREAM, the ECRYPT Stream Cipher project in 2005. The Big Encryption System (BES) is a block cipher introduced at CRYPTO 2002 which facilitates the algebraic analysis of the AES block cipher. In this article, experiments were conducted to find solutions of equation systems describing small scale LEX-BES using Gröbner Basis computations. This follows a similar approach to the work by Cid, Murphy and Robshaw at FSE 2005 that investigated algebraic cryptanalysis on small scale variants of the BES. The difference between LEX-BES and BES is that due to the way the keystream is extracted, the number of unknowns in LEX-BES equations is fewer than the number in BES. As far as the authors know, this attempt is the first at creating solvable equation systems for stream ciphers based on the LEX method using Gröbner Basis computations.
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We present several new observations on the SMS4 block cipher, and discuss their cryptographic significance. The crucial observation is the existence of fixed points and also of simple linear relationships between the bits of the input and output words for each component of the round functions for some input words. This implies that the non-linear function T of SMS4 does not appear random and that the linear transformation provides poor diffusion. Furthermore, the branch number of the linear transformation in the key scheduling algorithm is shown to be less than optimal. The main security implication of these observations is that the round function is not always non-linear. Due to this linearity, it is possible to reduce the number of effective rounds of SMS4 by four. We also investigate the susceptibility of SMS4 to further cryptanalysis. Finally, we demonstrate a successful differential attack on a slightly modified variant of SMS4. These findings raise serious questions on the security provided by SMS4.
Resumo:
The number of Australian children requiring foster care due to abuse and neglect is increasing at a faster rate than suitable carers can be recruited. Currently increased numbers of foster children are presenting with higher care needs. Evidence suggests carers with a higher education could contribute to placement stability and ultimately provide more positive outcomes for this group of children. This paper explores the level of interest by tertiary educated persons toward a model of fostering for children with higher needs. Using a descriptive survey methodology, a convenience sample of 644 university undergraduate and postgraduate students within faculties of health sciences, and education, arts and social sciences was employed. Psychology students in the 17-26 year old age group showed greatest interest in a professional foster care model and this was statistically significant (p=0.002 955 CI .000-.010) when compared to other health professionals and other age groups. Education students held the highest interest in general fostering although not statistically significant. When these survey results were extrapolated to the total number of health professionals in Australia there could be 8,385 potential recruits for a model professional foster care. Focused campaigns are required to source professional as recruits to fostering with the benefit of servicing the placement needs of higher care needs children and contributing to general foster care resources.
Resumo:
This is the second part of a paper that explores a range of magico-religious experiences such as immaterial voices and visions, in terms of local cultural, moral and socio-political circumstances in an Aboriginal town in rural Queensland. This part of the paper explores the political and cultural symbolism and meaning of suicide. It charts the saliency of suicide amongst two groups of kin and cohorts and the social meaningfulness and problematic of the voices and visions in relation to suicide, to identity and family forms and to funerals and a heavily drinking lifestyle. I argue that voices and visions are used to reinterpret social experience and to establish meaning and that tragically suicide evokes connectivity rather than anomie and here cannot be understood merely as an individualistic act or evidence of individual pathology. Rather it is about transformation and crossing a threshold to join an enduring domain of Aboriginality. In this life world, where family is the highest social value and where a relational view of persons holds sway, the individualistic practice of psychiatric and other helping professions, is a considerable problem.
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This booklet is the third in the Research in Practice Series, designed to complement Belonging, being & becoming: The Early Years Learning Framework for Australia (DEEWR, 2009). It focuses on Learning Outcome 5 of the Early Years Learning Framework (EYLF): Children are effective communicators (DEEWR, 2009).
Resumo:
Background Energy conserving processes reported in undernourished women during pregnancy are a recognised strategy to provide energy required to support fetal development. Women who are obese before conceiving arguably have sufficient fat stores to support the energy demands of pregnancy without the need to provoke energy conserving mechanisms. Objective We tested the hypothesis that obese women would demonstrate behavioural adaptation (i.e. decrease in self-selected walking (SSW) speed) but not metabolic compensation (i.e. decrease in resting metabolic rate (RMR) or metabolic cost of walking) during gestation. Design RMR, SSW speed, metabolic cost of walking, and anthropometry were measured in 23 women (BMI: 33.6 ± 2.5 kg/m2; 31 ± 4 years) at approximately weeks 15 (wk 15) and 30 (wk 30) of gestation. RMR was also measured in two cohorts of non-pregnant controls matched for age, weight and height of the pregnant cohort at wk 15 (N=23) and wk 30 (N=23). Results GWG varied widely (11.3 ± 5.4 kg) and 52% of women gained more weight than is recommended. RMR increased significantly by an average 177 ± 176 kcal/d (11±12%; P<0.0001); however the within-group variability was large. Both the metabolic cost of walking and SSW speed decreased significantly (P<0.01). While RMR increased in >80% of the cohort, the net oxygen cost of walking decreased in the same proportion of women. Conclusions While the increase in RMR was greater than was explained by weight gain, there was evidence of both behavioural and biological compensation in the metabolic cost of walking in obese women during gestation.
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An initialisation process is a key component in modern stream cipher design. A well-designed initialisation process should ensure that each key-IV pair generates a different key stream. In this paper, we analyse two ciphers, A5/1 and Mixer, for which this does not happen due to state convergence. We show how the state convergence problem occurs and estimate the effective key-space in each case.
Resumo:
For almost a half century David F. Treafust has been an exemplary science educator who has contributed through his dedication and commitments to students, curriculum development and collaboration with teachers, and cutting edge research in science education that has impacted the field globally, nationally and locally. A hallmark of his outstanding career is his collaborative style that inspires others to produce their best work.
Resumo:
How can Australian library and information science (LIS) education produce, in a sustainable manner, the diverse supply of graduates with the appropriate attributes to develop and maintain high quality professional practice in the rapidly changing 21st century? This report presents the key findings of a project that has examined this question through research into future directions for LIS education in Australia. Titled Re-conceptualising and re-positioning Australian library and information science education for the twenty-first century, the purpose of the project was to establish a consolidated and holistic picture of the Australian LIS profession, and identify how its future education and training can be mediated in a cohesive and sustainable manner. The project was undertaken with a team of 12 university and vocational LIS educators from 11 institutions around Australia between November 2009 and December 2010. Collectively, these eleven institutions represented the broad spectrum and diversity of LIS education in Australia, and enabled the project to examine education for the information profession in a holistic and synergistic manner. Participating institutions in the project included Queensland University of Technology (Project Leader), Charles Sturt University, Curtin University of Technology, Edith Cowan University, Monash University, RMIT University, University of Canberra, University of South Australia, University of Tasmania, University of Technology Sydney and Victoria University. The inception and need for the project was motivated by a range of factors. From a broad perspective several of these factors relate to concerns raised at national and international levels regarding problems with education for LIS. In addition, the motivation and need for the project also related to some unique challenges that LIS education faces in the Australian tertiary education landscape. Over recent years a range of responses to explore the various issues confronting LIS education in Australia have emerged at local and national levels however this project represented the first significant investment of funding for national research in this area. In this way, the inception of the project offered a unique opportunity and powerful mechanism through which to bring together key stakeholders and inspire discourse concerning future education for the profession. Therefore as the first national project of its kind, its intent has been to provide foundation research that will inform and guide future directions for LIS education and training in Australia. The primary objective of the project was to develop a Framework for the Education of the Information Professions in Australia. The purpose of this framework was to provide evidence based strategic recommendations that would guide Australia’s future education for the information professions. Recognising the three major and equal players in the education process the project was framed around three areas of consideration: LIS students, the LIS workforce and LIS educators. Each area of consideration aligned to a research substudy in the project. The three research substudies were titled Student Considerations, Workforce Planning Considerations and Tertiary Education Considerations. The Students substudy provided a profile of LIS students and an analysis of their choices, experiences and expectations in regard to LIS education and their graduate destinations. The Workforce substudy provided an overview and analysis of the nature of the current LIS workforce, including a focus on employer expectations and employment opportunities and comment on the core and elective skill, knowledge and attitudes of current and future LIS professionals. Finally the Tertiary Education substudy provided a profile of LIS educators and an analysis of their characteristics and experiences including the key issues and challenges. In addition it also explored current national and international trends and priorities impacting on LIS education. The project utilised a Community Based Participatory Research (CBPR) approach. This approach involves all members of the community in all aspects of the project. It recognised the unique strengths and perspectives that community members bring to the process. For this project ‘community’ comprised of all individuals who have a role in, or a vested interest in, LIS education and included LIS educators, professionals, employers, students and professional associations. Individuals from these sub-groups were invited to participate in a range of aspects of the project from design through to implementation and evaluation. A range of research methodologies were used to consider the many different perspectives of LIS education, including employers and recruiters, professional associations, students, graduates and LIS teaching staff. Data collection involved a mixed method approach of questionnaires, focus groups, semi-structured interviews and environmental scans. An array of approaches was selected to ensure that broadest possible access to different facets of the information profession would be achieved. The main findings and observations from each substudy have highlighted a range of challenges for LIS education that need to be addressed. These findings and observations have grounded the development of the Framework for the Education of the Information Professions in Australia. The framework presents eleven recommendations to progress the national approach to LIS education and guide Australia’s future education for the information professions. The framework will be used by the LIS profession, most notably its educators, as strategic directions for the future of LIS education in Australia. Framework for the Education of the Information Professions in Australia: Recommendation 1: It is recommended that a broader and more inclusive vocabulary be adopted that both recognises and celebrates the expanding landscape of the field, for example ‘information profession’, ‘information sector’, ‘information discipline’ and ‘information education’. Recommendation 2: It is recommended that a self-directed body composed of information educators be established to promote, support and lead excellence in teaching and research within the information discipline. Recommendation 3: It is recommended that Australia’s information discipline continue to develop excellence in information research that will raise the discipline’s profile and contribute to its prominence within the national and international arena. Recommendation 4: It is recommended that further research examining the nature and context of Australia’s information education programs be undertaken to ensure a sustainable and relevant future for the discipline. Recommendation 5: It is recommended that further research examining the pathways and qualifications available for entry into the Australian information sector be undertaken to ensure relevance, attractiveness, accessibility and transparency. Recommendation 6: It is recommended that strategies are developed and implemented to ensure the sustainability of the workforce of information educators. Recommendation 7: It is recommended that a national approach to promoting and marketing the information profession and thereby attracting more students to the field is developed. Recommendation 8: It is recommended that Australia’s information discipline continues to support a culture of quality teaching and learning, especially given the need to accommodate a focus on the broader information landscape and more flexible delivery options. Recommendation 9: It is recommended that strategies are developed that will support and encourage collaboration between information education within the higher education and VET sectors. Recommendation 10: It is recommended that strategies and forums are developed that will support the information sector working together to conceptualise and articulate their professional identity and educational needs. Recommendation 11: It is recommended that a research agenda be established that will identify and prioritise areas in which further development or work is needed to continue advancing information education in Australia. The key findings from this project confirm that a number of pressing issues are confronting LIS education in Australia. Left unaddressed these issues will have significant implications for the future of LIS education as well as the broader LIS profession. Consequently creating a sustainable and cohesive future can only be realised through cooperation and collaboration among all stakeholders including those with the capacity to enact radical change in university and vocational institutions. Indeed the impending adoption and implementation of the project’s recommendations will fundamentally determine whether Australian LIS education is assured both for the present day and into the future.
Resumo:
Various time-memory tradeoffs attacks for stream ciphers have been proposed over the years. However, the claimed success of these attacks assumes the initialisation process of the stream cipher is one-to-one. Some stream cipher proposals do not have a one-to-one initialisation process. In this paper, we examine the impact of this on the success of time-memory-data tradeoff attacks. Under the circumstances, some attacks are more successful than previously claimed while others are less. The conditions for both cases are established.