70 resultados para universal designated verifier signature

em Deakin Research Online - Australia


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In Asiacrypt 2003, the concept of universal designated verifier signature (UDVS) was introduced by Steinfeld, Bull, Wang and Pieprzyk. In the new paradigm, any signature holder (not necessarily the signer) can designate the publicly verifiable signature to any desired designated verifier (using the verifier’s public key), such that only the designated verifier can believe that the signature holder does have a valid publicly verifiable signature, and hence, believes that the signer has signed the message. Any other third party cannot believe this fact because this verifier can use his secret key to create a valid UDVS which is designated to himself. In ACNS 2005, Zhang, Furukawa and Imai proposed the first UDVS scheme without random oracles. In this paper, we give a security analysis to the scheme of Zhang et al. and propose a novel UDVS scheme without random oracles based on Waters’ signature scheme, and prove that our scheme is secure under the Gap Bilinear Diffie Hellman assumption

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The notion of strong designated verifier signature was put forth by Jakobsson, Sako and Impagliazzo in 1996, but the formal definition was defined recently by Saeednia, Kremer and Markowitch in 2003 and revisited by Laguil- laumie and Vergnaud in 2004. In this paper, we firstly propose the notion of short strong designated verifier sig- nature scheme, and extend it to the short identity-based strong designated verifier scheme. Then, we propose the first construction of short strong designated verifier sig- nature scheme. We also extend our scheme to construct a short identity-based strong designated verifier signature scheme. The size of the signature of our schemes is the shortest compared to any existing schemes reported in the literature. We provide formal security proofs for our schemes based on the random oracle model. Finally, we also discuss an extension of our scheme to construct a short strong designated verifier signature without random oracle.

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Certificateless cryptography has attracted a lot of attention from the research community, due to its applicability in information security. In this paper, we analyze two recently proposed certificateless signature schemes and point out their security flaws. In particular, we demonstrate universal forgeries against these schemes with known message attacks

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The acceptance/rejection approach is widely used in universal nonuniform random number generators. Its key part is an accurate approximation of a given probability density from above by a hat function. This article uses a piecewise constant hat function, whose values are overestimates of the density on the elements of the partition of the domain. It uses a sawtooth overestimate of Lipschitz continuous densities, and then examines all local maximizers of such an overestimate. The method is applicable to multivariate multimodal distributions. It exhibits relatively short preprocessing time and fast generation of random variates from a very large class of distributions

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The principle of proportionality prescribes that the punishment should equal the crime. It is one of the most important principles of sentencing. Yet, despite its widespread acceptance it offers no meaningful guide to sentencing. Hence penalty levels fluctuate greatly between jurisdictions and within jurisdictions. This is because there is no universally agreed criterion for measuring offence seriousness or penalty severity. This article suggests that the appropriate criteria for matching offence seriousness and penalty severity is the level of unhappiness or pain stemming from each of these impositions. Thus, for example, the level of pain meted out to a rape offender should equal the level of pain caused to a rape victim. Emerging scientific studies on human well-being and happiness show that human beings are similarly built in terms of the experiences that are either conducive or inimical to well-being. This commonality provides a strong foundation to be confident to make reasonably accurate predictions concerning the extent to which adverse events, such as being the victim of a criminal offence or subjected to a form of criminal sanction will stifle human flourishing. This will then allow us to match accurately offence seriousness and penalty level.

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While the Australian Government partly justified the introduction of a universal National Service Training Scheme for eighteen-year old males in 1951 by highlighting the threat of imminent war and the consequent need for military preparedness, advocates also believed that national service encouraged the development of a sense of civil responsibility. Its confidence in the potential of national service to promote citizenship explains why the government was so strongly committed to the scheme's universality. Nonetheless, although the government went to great lengths to enforce compliance, Aborigines and those from other "non-white" backgrounds were actively discouraged from participation and women were only reluctantly admitted to the professional army. As would be expected in this period, they were never considered for national service. An examination of the rationale for national service and the associated discourse for inclusion and exclusion not only indicates the social assumptions shaping policy-making by government and bureaucratic elites in 1950s Australia, but also reveals their wider social aspirations.

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While increased awareness of disability issues has resulted in the development of guidelines for developing accessible software, such guidelines do not guarantee that the end product will be optimal for users with a disability. We present an overview of a user-centred approach to the needs analysis and ultimate design of a disability aware email client (Multimail). We discuss the process we used to work with participants in developing the software and reflect on the benefits and challenges of the process.

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It has been possible to nominate places for their cultural landscape values to the World Heritage List since December 1992. The Operational Guidelines (2005) define cultural landscapes as cultural properties that ‘represent the “combined works of nature and man” designated in Article 1 of the Convention’. They are illustrative of the evolution of human society and settlement over time, under the influence of the physical constraints and/or opportunities presented by their natural environment and of successive social, economic and cultural forces, both internal and external’ (Para 47). Refining this further, the World Heritage system recognises three categories of cultural landscapes:

1. Clearly defined landscapes designed and intentionally created by man;

2. Organically evolved landscapes of two subtypes:
·  Relict or fossil landscapes in which an evolutionary process has come to an end but where its distinguishing features are still visible;
·  Continuing landscapes which retain an active social role in contemporary society associated with a traditional way of life and in which the evolutionary process is still in progress and where it exhibits significant material evidence of its evolution over time;

3. Associative cultural landscapes where the outstanding universal value relates to the powerful religious, artistic, or cultural associations of the natural elements rather than the evidence of material culture.

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Researchers worldwide have been actively seeking for the most robust and powerful solutions to detect and classify key events (or highlights) in various sports domains. Most approaches have employed manual heuristics that model the typical pattern of audio-visual features within particular sport events To avoid manual observation and knowledge, machine-learning can be used as an alternative approach. To bridge the gaps between these two alternatives, an attempt is made to integrate statistics into heuristic models during highlight detection in our investigation. The models can be designed with a modest amount of domain-knowledge, making them less subjective and more robust for different sports. We have also successfully used a universal scope of detection and a standard set of features that can be applied for different sports that include soccer, basketball and Australian football. An experiment on a large dataset of sport videos, with a total of around 15 hours, has demonstrated the effectiveness and robustness of our
aIlgorithms.

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I. The Evolution of International Criminal Law International criminal justice concerns breaches of international rules entailing the personal criminal liability of individuals (as opposed to the State for which the individuals may act as agents or organs), and presently includes acts such as genocide, torture, crimes against humanity, aggression and terrorism. ... A rule stating: any act of armed conflict which directly causes the death of a civilian is a war crime unless it can be shown that the military advantage gained by the attack outweighs the harm. ... Thus, so far as international criminal law is concerned any act during armed conflict which results in the death or injury to a person who does not pose a direct threat to the life of the accused should be a war crime. ... Pursuant to the Rome Statute and as a matter of customary international law torture is a war crime when performed in the context of an armed conflict, and a crime against humanity when it is part of systematic criminal conduct. ... Torture can also constitute an individual international crime, even where it does not satisfy the criteria of a war crime or crime against humanity. ...

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This thesis describes the exploration and the development of computational means to investigate the behaviour of design objects before they are available for investigation in the physical world. The motivation is to inform the design process about the design object's performance in order to achieve better--more performance-oriented--design outcomes in the sense of energy efficiency and comfort performance than can be achieved by conventional design techniques.

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Focused ion beam (FIB) milling system has been used to create nanosized patterns as the template for patterned growth of carbon nanotubes on Si substrate surface without predeposition of metal catalysts. Carbon nanotubes only nucleate and grow on the template under controlled pyrolysis of iron phthalocyanine at 1000 °C. The size, growth direction, and density of the patterned nanotubes can be controlled under different growth conditions and template sizes. Atomic force microscopy and electron microscopy analyses reveal that the selective growth on the FIB template is due to its special surface morphology and crystalline structure.