935 resultados para Secure Actions, Homomorphic Encryption, Electronic Commerce


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In this paper, we show implementation results of various algorithms that sort data encrypted with Fully Homomorphic Encryption scheme based on Integers. We analyze the complexities of sorting algorithms over encrypted data by considering Bubble Sort, Insertion Sort, Bitonic Sort and Odd-Even Merge sort. Our complexity analysis together with implementation results show that Odd-Even Merge Sort has better performance than the other sorting techniques. We observe that complexity of sorting in homomorphic domain will always have worst case complexity independent of the nature of input. In addition, we show that combining different sorting algorithms to sort encrypted data does not give any performance gain when compared to the application of sorting algorithms individually.

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Homomorphic encryption offers potential for secure cloud computing. However due to the complexity of homomorphic encryption schemes, performance of implemented schemes to date have been unpractical. This work investigates the use of hardware, specifically Field Programmable Gate Array (FPGA) technology, for implementing the building blocks involved in somewhat and fully homomorphic encryption schemes in order to assess the practicality of such schemes. We concentrate on the selection of a suitable multiplication algorithm and hardware architecture for large integer multiplication, one of the main bottlenecks in many homomorphic encryption schemes. We focus on the encryption step of an integer-based fully homomorphic encryption (FHE) scheme. We target the DSP48E1 slices available on Xilinx Virtex 7 FPGAs to ascertain whether the large integer multiplier within the encryption step of a FHE scheme could fit on a single FPGA device. We find that, for toy size parameters for the FHE encryption step, the large integer multiplier fits comfortably within the DSP48E1 slices, greatly improving the practicality of the encryption step compared to a software implementation. As multiplication is an important operation in other FHE schemes, a hardware implementation using this multiplier could also be used to improve performance of these schemes.

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Organizing and managing channels of distribution is an important marketing task. Due to the emergence of electronic commerce on the Internet, e-channel distribution systems have been adopted by many manufacturers. However, academic and anecdotal evidence both point to the pressures arising from this new e-channel manufacturing environment. Questions marks therefore remain on how the addition of this e-channel affects the traditional marketing strategies of leasing and selling. We set up several two-period dual-channel models in which a manufacturer sells a durable product through both a manufacturer-owned e-channel and an independent reseller (leaser) who adopts selling (leasing) to consumers. Our main results indicate that, direct selling cost aside, product durability plays an important role in shaping the strategies of all members. With either marketing strategy, the additional expansion of an e-channel territory may secure Pareto gains, in which all members benefit.

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Os Mercados Eletrónicos atingiram uma complexidade e nível de sofisticação tão elevados, que tornaram inadequados os modelos de software convencionais. Estes mercados são caracterizados por serem abertos, dinâmicos e competitivos, e constituídos por várias entidades independentes e heterogéneas. Tais entidades desempenham os seus papéis de forma autónoma, seguindo os seus objetivos, reagindo às ocorrências do ambiente em que se inserem e interagindo umas com as outras. Esta realidade levou a que existisse por parte da comunidade científica um especial interesse no estudo da negociação automática executada por agentes de software [Zhang et al., 2011]. No entanto, a diversidade dos atores envolvidos pode levar à existência de diferentes conceptualizações das suas necessidades e capacidades dando origem a incompatibilidades semânticas, que podem prejudicar a negociação e impedir a ocorrência de transações que satisfaçam as partes envolvidas. Os novos mercados devem, assim, possuir mecanismos que lhes permitam exibir novas capacidades, nomeadamente a capacidade de auxiliar na comunicação entre os diferentes agentes. Pelo que, é defendido neste trabalho que os mercados devem oferecer serviços de ontologias que permitam facilitar a interoperabilidade entre os agentes. No entanto, os humanos tendem a ser relutantes em aceitar a conceptualização de outros, a não ser que sejam convencidos de que poderão conseguir um bom negócio. Neste contexto, a aplicação e exploração de relações capturadas em redes sociais pode resultar no estabelecimento de relações de confiança entre vendedores e consumidores, e ao mesmo tempo, conduzir a um aumento da eficiência da negociação e consequentemente na satisfação das partes envolvidas. O sistema AEMOS é uma plataforma de comércio eletrónico baseada em agentes que inclui serviços de ontologias, mais especificamente, serviços de alinhamento de ontologias, incluindo a recomendação de possíveis alinhamentos entre as ontologias dos parceiros de negociação. Este sistema inclui também uma componente baseada numa rede social, que é construída aplicando técnicas de análise de redes socias sobre informação recolhida pelo mercado, e que permite melhorar a recomendação de alinhamentos e auxiliar os agentes na sua escolha. Neste trabalho são apresentados o desenvolvimento e implementação do sistema AEMOS, mais concretamente: • É proposto um novo modelo para comércio eletrónico baseado em agentes que disponibiliza serviços de ontologias; • Adicionalmente propõem-se o uso de redes sociais emergentes para captar e explorar informação sobre relações entre os diferentes parceiros de negócio; • É definida e implementada uma componente de serviços de ontologias que é capaz de: • o Sugerir alinhamentos entre ontologias para pares de agentes; • o Traduzir mensagens escritas de acordo com uma ontologia em mensagens escritas de acordo com outra, utilizando alinhamentos previamente aprovados; • o Melhorar os seus próprios serviços recorrendo às funcionalidades disponibilizadas pela componente de redes sociais; • É definida e implementada uma componente de redes sociais que: • o É capaz de construir e gerir um grafo de relações de proximidade entre agentes, e de relações de adequação de alinhamentos a agentes, tendo em conta os perfis, comportamento e interação dos agentes, bem como a cobertura e utilização dos alinhamentos; • o Explora e adapta técnicas e algoritmos de análise de redes sociais às várias fases dos processos do mercado eletrónico. A implementação e experimentação do modelo proposto demonstra como a colaboração entre os diferentes agentes pode ser vantajosa na melhoria do desempenho do sistema e como a inclusão e combinação de serviços de ontologias e redes sociais se reflete na eficiência da negociação de transações e na dinâmica do mercado como um todo.

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Este é um estudo sobre o perfil do e-consumidor brasileiro. Através de um enquadramento do ecommerce no Brasil e de uma pesquisa qualitativa, o trabalho busca identificar quem é este consumidor, o que ele compra, porque ele compra online, como coleta as informações necessárias para escolher um produto ou serviço, quais são os fatores determinantes da compra e quais os locais escolhidos.

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"Mémoire présenté à la Faculté des études supérieures en vue de l'obtention du grade de Maîtrise en droit (LLM)"

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"Thèse en vue de l'obtention du grade de docteur en droit de l'Université Panthéon-Assas (Paris II) et de docteur en droit de la faculté de droit de l'Université de Montréal en droit privé"

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Le sujet sur lequel porte la présente étude est inspiré de la problématique à la base du développement du commerce électronique : la confiance. En effet, l’accroissement exponentiel du nombre d’internautes et des sites Web commerciaux pose un sérieux problème à ce niveau. Ces sites présentent au public une information et des services divers, mais peu vérifiables. Ainsi, le principal obstacle au développement du commerce électronique avec les particuliers est le manque de confiance qu’inspirent les lieux visités. En effet, comment savoir si l’entreprise existe, quelles sont ses politiques concernant la sécurité ou la gestion des renseignements personnels, etc. La vérification et la certification des sites apparaissent comme une solution de plus en plus attrayante et utilisée pour ajouter cet élément de confiance. Déjà, de nombreux sceaux de qualité sont apparus sur les sites commerciaux. Certains sceaux portent sur la confidentialité tandis que d’autres ciblent la protection des consommateurs. La certification peut provenir de la compagnie même, d’un tiers certificateur ou d’un organisme public. Ces éléments constituent des balises et repères importants pour le consommateur sur Internet. Toutefois, les incidences légales sont multiples et certains concepts demeurent flous. Pour apporter une réponse à ces questions, nous définirons le concept de certification des sites Web et ses enjeux dont plus particulièrement la problématique de la confiance des consommateurs. Les différents objets de la certification seront analysés, tant au niveau de l’entité, du contenu du site que de la dimension transactionnelle de celui-ci. Les processus possibles et les impacts de la certification occupent la seconde partie du travail. Il s’agit d’examiner successivement les étapes menant à la certification, soit l’établissement des standards, de l’évaluation de l’entité et de la certification elle-même. L’analyse des impacts de la certification, tant sur le plan de la portée, de la responsabilité légale et des effets sur la concurrence de la certification constitue quant à eux, l’aboutissement de la recherche, soit de savoir quel est l’impact juridique d’un tel mécanisme. Le but de la recherche est de permettre au lecteur de mieux cerner ce phénomène de l’utilisation de la certification sur Internet avec ses avantages et ses limites. Certes, cet outil peut s’avérer très utile pour bâtir la confiance des consommateurs, promouvoir l’essor du commerce électronique et constituer une forme d’autoréglementation. Toutefois, mal utilisé ou mal encadré, il peut engendrer l’effet inverse et détruire cette confiance si fragile à construire dans un environnement dématérialisé.

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Cet article délivre un bref aperçu de la nouvelle législation européenne et allemande relative au commerce électronique et à la protection des consommateurs. Il décrit le développement du commerce électronique, de la législation et de la jurisprudence au cours des dernières années. Une distinction est établie entre les niveaux européen et allemand. La nouvelle Directive sur le commerce électronique a été adoptée le 8 juin 2000 et doit être transposée dans la loi nationale avant le 17 janvier 2002. Elle sera décrite et succinctement analysée avant d’aborder la nouvelle loi allemande portant sur les contrats à distance qui vient d’être adoptée par le Parlement allemand pour transposer la Directive sur les contrats à distance de 1997. Le cadre juridique existant avant l’entrée en vigueur de la nouvelle loi sur les contrats à distance sera également exposée en tenant compte de la protection des consommateurs. Alors que l’Union européenne vient de créer une nouvelle Directive sur le commerce électronique, les États membres sont encore occupés à transformer celle de 1997 en loi nationale. En comparant la législation européenne et allemande, nous soulignerons donc le point faible de la législation européenne : le temps nécessaire pour établir un cadre juridique efficace et fonctionnel peut facilement atteindre plusieurs années. L’article s’achèvera sur une courte présentation du « powershopping » ou « community shopping », en passe de devenir un nouveau modèle pour le consommateur européen, qui a fait l’objet de décisions restrictives ces derniers temps.

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In the context of the digital business ecosystems, small organizations cooperate between them in order to achieve common goals or offer new services for expanding their markets. There are different approaches for these cooperation models such as virtual enterprises, virtual organizations or dynamic electronic institutions which in their lifecycle have in common a dissolution phase. However this phase has not been studied deeply in the current literature and it lacks formalization. In this paper a first approach for achieving and managing the dissolution phase is proposed, as well as a CBR process in order to support it in a multi-agent system

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Persuasive technologies have been extensively applied in the context of e-commerce for the purpose of marketing, enhancing system credibility, and motivating users to adopt the systems. Recognising that persuasion impacts on consumer behaviour to purchase online have not been investigated previously. This study reviews theories of technology acceptance, and identifies their limitation in not considering the effect of persuasive technologies when determining user online technology acceptance. The study proposes a theoretical model that considers the effect of persuasive technologies on consumer acceptance of e-commerce websites; with consideration of other related variables, i.e. trust and technological attributes. Moreover the paper proposes a model based on the UTAUT2, which contains relevant contributing factors; including the concept of perceived persuasiveness.

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As a continually growing financial service of electronic commerce, Internet banking requires the development and implementation of a sound security procedure. This involves designing effective methods via which users can
be authenticated in a remote environment. Specifically for Internet banking there is areal need for away uniquely to identify and authenticate users without the possibility of their authenticity being cloned. Some technologies in use have been presented for meeting the security requirements for national, regional and global Internet banking assurance. However, there has been little research conducted particularly on the creation of secure
and trusted pathways. Concentrates on presenting a security framework for Internet banking based on discovering and defining these pathways in terms of adequate authentication mechanisms. Proposes a framework concerning how to identify security requirements for Internet banking such that the
transactions being conducted are secured within their respective environments.

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Purpose: Online education has been growing rapidly, but has not had the benefit of the extensive teaching pedagogy development of traditional face-to-face teaching. This paper aims to provide a review of the current literature and present the results of a survey, conducted to determine the effectiveness of a graduate online subject. Design/methodology/approach: The literature was reviewed to identify measures of success and quality in online education delivery. These measures were then considered in relation to their application in practice via a case study based around a survey conducted at Deakin University in Australia. Findings: A total of 16 relevant measures of teaching quality were identified in the literature. Most measures had elements of bias and some were more generally applicable to online learning. The case study suggested that the value of computer mediated learning in an online environment was limited and that a combination of print and computer mediated conferencing performed better in more of the identified quality matrices. Practice implications: Online learning does not save teaching resources if standards of quality are maintained. It can be used to provide a remote teaching facility, provided it is backed up by resources such as printed study guides. For the subject evaluated, online mediated learning did not the provide the same quality of education. Originality/value: Whilst some research has been conducted in this area, no substantive grounded theory has been applied to postgraduate or fee-paying online education regimes. As a result, case studies of such applications can be very helpful in the design of future teaching systems.

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E-commerce security is a complex issue; it is concerned with a number of security risks that can appear at either a technical level or organisational level. This paper uses a systemic framework, the viable system model (VSM) to determine the high level security risks and then uses baseline security methods to determine the lower level security risks.