951 resultados para Security community
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We present some improved analytical results as part of the ongoing work on the analysis of Fugue-256 hash function, a second round candidate in the NIST’s SHA3 competition. First we improve Aumasson and Phans’ integral distinguisher on the 5.5 rounds of the final transformation of Fugue-256 to 16.5 rounds. Next we improve the designers’ meet-in-the-middle preimage attack on Fugue-256 from 2480 time and memory to 2416. Finally, we comment on possible methods to obtain free-start distinguishers and free-start collisions for Fugue-256.
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Halevi and Krawczyk proposed a message randomization algorithm called RMX as a front-end tool to the hash-then-sign digital signature schemes such as DSS and RSA in order to free their reliance on the collision resistance property of the hash functions. They have shown that to forge a RMX-hash-then-sign signature scheme, one has to solve a cryptanalytical task which is related to finding second preimages for the hash function. In this article, we will show how to use Dean’s method of finding expandable messages for finding a second preimage in the Merkle-Damgård hash function to existentially forge a signature scheme based on a t-bit RMX-hash function which uses the Davies-Meyer compression functions (e.g., MD4, MD5, SHA family) in 2 t/2 chosen messages plus 2 t/2 + 1 off-line operations of the compression function and similar amount of memory. This forgery attack also works on the signature schemes that use Davies-Meyer schemes and a variant of RMX published by NIST in its Draft Special Publication (SP) 800-106. We discuss some important applications of our attack.
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Protection of passwords used to authenticate computer systems and networks is one of the most important application of cryptographic hash functions. Due to the application of precomputed memory look up attacks such as birthday and dictionary attacks on the hash values of passwords to find passwords, it is usually recommended to apply hash function to the combination of both the salt and password, denoted salt||password, to prevent these attacks. In this paper, we present the first security analysis of salt||password hashing application. We show that when hash functions based on the compression functions with easily found fixed points are used to compute the salt||password hashes, these hashes are susceptible to precomputed offline birthday attacks. For example, this attack is applicable to the salt||password hashes computed using the standard hash functions such as MD5, SHA-1, SHA-256 and SHA-512 that are based on the popular Davies-Meyer compression function. This attack exposes a subtle property of this application that although the provision of salt prevents an attacker from finding passwords, salts prefixed to the passwords do not prevent an attacker from doing a precomputed birthday attack to forge an unknown password. In this forgery attack, we demonstrate the possibility of building multiple passwords for an unknown password for the same hash value and salt. Interestingly, password||salt (i.e. salts suffixed to the passwords) hashes computed using Davies-Meyer hash functions are not susceptible to this attack, showing the first security gap between the prefix-salt and suffix-salt methods of hashing passwords.
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This study addresses the under-researched area of community sport in rurally isolated contexts. Data were gathered using semi-structured interviews with teachers, children, parents, and local community members from a small township in an isolated North Queensland region. The data indicate that community sport for young people is circumstantially difficult in some regional centres, but is none-the-less viewed differently by different sectors of the community. There is much value ascribed to sport as part of the social and cultural capital of the area however, it appears that community opinion is divided on the quality of sport experiences available with the young people of the community being particularly critical of the facilities, equipment, and the level of service from sports organisations in larger towns and cities.
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Problem, research strategy and findings: On January 10, 2011, the town of Grantham, Queensland (Australia), was inundated with a flash flood in which 12 of the town's 370 residents drowned. The overall damage bill in Queensland was AUD∃2.38 billion (USD∃2.4 billion) with 35 deaths, and more than three-quarters of the state was declared a flood disaster zone. In this study, we focus on the unusual and even rare decision to relocate Grantham in March 2011. The Lockyer Valley Regional Council (LVRC) acquired a 377-hectare (932-acre) site to enable a voluntary swap of equivalent-sized lots. In addition, planning regulations were set aside to streamline the relocation of a portion of the town. We review the natural hazard literature as it relates to community relocation, state and local government documents related to Grantham, and reports and newspaper articles related to the flood. We also analyze data from interviews with key stakeholders. We document the process of community relocation, assess the relocation process in Grantham against best practice, examine whether the process of community relocation can be upscaled and if the Grantham relocation is an example of good planning or good politics. Takeaway for practice: Our study reveals two key messages for practice. Community relocation (albeit a small one) is possible, and the process can be done quickly; some Grantham residents moved into their new, relocated homes in December 2012, just 11 months after the flood. Moreover, the role of existing planning regulations can be a hindrance to quick action; political leadership, particularly at the local level, is key to implementing the relocation.
‘It’s about finding a way’ : children, sites of opportunity, and building everyday peace in Colombia
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The multiple forms of violence associated with protracted conflict disproportionately affect young people. Literature on conflict-affected children often focuses on the need to provide stability and security through institutions such as schools but rarely considers how young people themselves see these sites as part of their everyday lives. The enduring, pervasive, and complex nature of Colombia’s conflict means many young Colombians face the challenges of poverty, persistent social exclusion, and violence. Such conditions are exacerbated in ‘informal’ barrio communities such as los Altos de Cazucá, just south of the capital Bogotá. Drawing on field research in this community, particularly through interviews conducted with young people aged 10 to 17 this article explores how young people themselves understand the roles of the local school and ngo in their personal conceptualisations of the violence in their everyday lives. The evidence indicates that children use spaces available to them opportunistically and that these actions can and should be read as contributing to local, everyday forms of peacebuilding. The ways in which institutional spaces are understood and used by young people as ‘sites of opportunity’ challenges the assumed illegitimacy of young people’s voices and experiences in these environments.
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Twenty first century society presents critical challenges for higher education (Brew 2013, 2). The challenges facing modern communities require graduates to have skills that respond to issues at the boundaries of, and intersections between, disciplines. Mounting evidence suggests that interdisciplinary curriculum and pedagogies help students to develop boundary-crossing skills and a deeper awareness of the student’s domain-specific knowledge (Spelt et al. 2009; Strober 2011). Spelt et al. (2009) describe boundary-crossing skills as the ability to engage with different discourses, take account of multiple perspectives, synthesise knowledge of different disciplines, and cope with complexity. In this chapter we investigate emerging conditions, practical processes, and pedagogical strategies that are enabling the Lab stakeholders, the community, the university, and students to participate in interdisciplinary community-engaged learning. Aspects of the Lab that are considered in this chapter include building trust, sharing values, establishing learning goals that are reflected in learning experiences and assessment, and employing strategies that define and attend to relationships and roles. The case study, “The Recognition of Aboriginal and Torres Strait Islander Peoples in the Australian Constitution”, a QUT collaborative project with the Social Justice Research Unit Anglicare Southern Queensland, describes the collaborators, processes, outcomes, and the lessons learned through one Lab project over three semesters. The issues illustrated in the case study are then further explored in a critical discussion of the strategies supporting interdisciplinarity in community-engaged learning across university/community collaboration, within and across the university, and for student participants
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The philosophical promise of community development to “resource and empower people so that they can collectively control their own destinies” (Kenny 1996:104) is no doubt alluring to Indigenous Australia. Given the historical and contemporary experiences of colonial control and surveillance of Aboriginal bodies, alongside the continuing experiences of socio-economic disadvantage, community development reaffirms the aspirational goal of Indigenous Australians for self-determination. Self-determination as a national policy agenda for Indigenous Australians emerged in the 1970s and saw the establishment of a wide range of Aboriginal community-controlled services (Tsey et al 2012). Sullivan (2010:4) argues that the Aboriginal community controlled service sector during this time has, and continues to be, instrumental to advancing the plight of Indigenous Australians both materially and politically. Yet community development and self-determination remain highly problematic and contested in how they manifest in Indigenous social policy agendas and in practice (Hollinsworth 1996; Martin 2003; McCausland 2005; Moreton-Robinson 2009). Moreton-Robinson (2009:68) argues that a central theme underpinning these tensions is a reading of Indigeneity in which Aboriginal and Torres Strait Islander people, behaviours, cultures, and communities are pathologised as “dysfunctional” thus enabling assertions that Indigenous people are incapable of managing their own affairs. This discourse distracts us from the “strategies and tactics of patriarchal white sovereignty” that inhibit the “state’s earlier policy of self-determination” (Moreton-Robinson 2009:68). We acknowledge the irony of community development espoused by Ramirez above (1990), that the least resourced are expected to be most resourceful.; however, we wish to interrogate the processes that inhibit Indigenous participation and control of our own affairs rather than further interrogate Aboriginal minds as uneducated, incapable and/or impaired...
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This chapter explores the dialectic meaning of ‘home’, and movement away from home. Movement away from home – migration – is characterized as a dynamic, dialectic, and developmental experience. We emphasize the sense of being at home and the intertwined sense of identity as interlinked and mutually defining anchors of our existence that become inevitably shaken and ruptured in the experience of migration. But when looking at how this rupture is experienced and managed, we highlight the inherently complex and dialectic nature of migration, instead of seeing it as a unidirectional sequence of rupture → shock → coping → new stable being. We discuss the complexities of migration experiences as entailing dialectics of home and non-home, rupture and continuity, novelty and everydayness, changing and remaining. The sense of being at home is simultaneously enabling and constraining, helping us to build self-continuity in a new environment, yet also holding us back and distancing us from novelty. Similarly, migration is a threat, yet also a promise; it is a painful, yet possibly exhilarating experience that makes us lose our centre of security and familiarity, yet also opens up opportunities for transformation and re-invention.
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A Bitcoin wallet is a set of private keys known to a user and which allow that user to spend any Bitcoin associated with those keys. In a hierarchical deterministic (HD) wallet, child private keys are generated pseudorandomly from a master private key, and the corresponding child public keys can be generated by anyone with knowledge of the master public key. These wallets have several interesting applications including Internet retail, trustless audit, and a treasurer allocating funds among departments. A specification of HD wallets has even been accepted as Bitcoin standard BIP32. Unfortunately, in all existing HD wallets---including BIP32 wallets---an attacker can easily recover the master private key given the master public key and any child private key. This vulnerability precludes use cases such as a combined treasurer-auditor, and some in the Bitcoin community have suspected that this vulnerability cannot be avoided. We propose a new HD wallet that is not subject to this vulnerability. Our HD wallet can tolerate the leakage of up to m private keys with a master public key size of O(m). We prove that breaking our HD wallet is at least as hard as the so-called "one more" discrete logarithm problem.
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Using data from 28 countries in four continents, the present research addresses the question of how basic values may account for political activism. Study 1 (N = 35,116) analyses data from representative samples in 20 countries that responded to the 21-item version of the Portrait Values Questionnaire (PVQ-21) in the European Social Survey. Study 2 (N = 7,773) analyses data from adult samples in six of the same countries (Finland, Germany, Greece, Israel, Poland, and United Kingdom) and eight other countries (Australia, Brazil, Chile, Italy, Slovakia, Turkey, Ukraine, and United States) that completed the full 40-item PVQ. Across both studies, political activism relates positively to self-transcendence and openness to change values, especially to universalism and autonomy of thought, a subtype of self-direction. Political activism relates negatively to conservation values, especially to conformity and personal security. National differences in the strength of the associations between individual values and political activism are linked to level of democratization.
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This video was prepared as a teaching resource for CARRS-Q's Under the Limit Drink Driving Rehabilitation Program
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Do the political values of the general public form a coherent system? What might be the source of coherence? We view political values as expressions, in the political domain, of more basic personal values. Basic personal values (e.g., security, achievement, benevolence, hedonism) are organized on a circular continuum that reflects their conflicting and compatible motivations. We theorize that this circular motivational structure also gives coherence to political values. We assess this theorizing with data from 15 countries, using eight core political values (e.g., free enterprise, law and order) and ten basic personal values. We specify the underlying basic values expected to promote or oppose each political value. We offer different hypotheses for the 12 non-communist and three post-communist countries studied, where the political context suggests different meanings of a basic or political value. Correlation and regression analyses support almost all hypotheses. Moreover, basic values account for substantially more variance in political values than age, gender, education, and income. Multidimensional scaling analyses demonstrate graphically how the circular motivational continuum of basic personal values structures relations among core political values. This study strengthens the assumption that individual differences in basic personal values play a critical role in political thought.
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Cochrane Journal Club resource for the Cochrane Systematic Review: Community wide interventions for increasing physical activity. The resource includes a power-point presentation describing the essential components of the paper, summary, Discussion points: a critical appraisal and an author profile.