[pt] O mashup, estilo musical popularizado a partir dos primeiros anos do século XXI, ilustra como a democratização do acesso à internet e também aos softwares de download e edição de música em arquivo digital trouxe o ouvinte/usuário para o protagonismo nas novas formas de composição. Com o advento de programas como o Napster e outras redes de trocas de arquivo em MP3, o cidadão teve acesso a ferramentas diversas e reconfigurou a noção de produção musical, além de, naquele momento, instaurar outros ambientes de interação social. O mashup, um dos principais campos estéticos em que ficaram claros esses meios de criação, consiste em escolher trechos de duas ou mais músicas e recombiná-las a partir da junção delas, criando uma terceira composição. Ficam estabelecidos, assim, outros meios de apropriação e uso de bens culturais, deslocando sentidos como autoria, originalidade, cópia e produção artística. Deste modo, as tecnologias disponíveis possibilitam o surgimento de artistas que criam com as obras de outros, recombinando criações para o surgimento de novos discursos. É a partir dos mashups que se busca enxergar uma geração calcada em novos modos de se relacionar tanto entre si quanto com os bens culturais produzidos e divulgados pela internet. / [en] Mashup, a musical genre popularized at the beginning of the XXI century, illustrates how the democratization of access to the Internet as well as to software downloads and to digital music publishing brought the listener/user to the role of new methods of music composition. With the advent of programs such as Napster and other MP3 file sharing networks, citizens had access to a wide range of tools, reconfiguring the notion of music production, and also bringing up other social interaction environments. Mashup, one of the main aesthetic fields in which these ways of creating became clear, consists of excerpts chosen from two or more songs which are recombined, originating a third one. Thenceforth other means of appropriation and also of making use of cultural goods have been established, moving senses of authorship, originality, copy and artistic production. Thus these available technologies allow the emergence of artists who create using someone else s work, recombining these creations to raise other kind of discourses. It is from the mashups that it is aimed to understand one generation that is developed in new ways of relationships between each other as much as of enjoying cultural goods produced and spread out on the Internet.

Drive-by download is a sort of network attack which uses different techniques to plant malicious codes in their computers. It makes the traditional intrusion detection systems and firewalls nonfunctional in the reason that those devices could not detect web-based threats. The Crawler-based approach has been proposed by many studies to discover drive-by download sites. However, the Crawler-based approach could not simulate the real user behavior of web browsing when drive-by download attack happens. Therefore, this study proposes a new approach to detect drive-by download by sniffing HTTP flow. This study uses reputation system to improve the efficiency of client honeypots, and adjusts client honeypots to process the raw data of HTTP flow. In the experiment conducted in real network environment, this study show the performance of a single client honeypot could reach average 560,000 HTTP success access log per day. Even in the peak traffic, this mechanism reduced the process time to 22 hours, and detected drive-by download sites that users were actually browsing. Reputation system in this study is applicable to varieties of domain names because it does not refer to online WHOIS database. It established classification model on machine learning in 12 features. The correct classification rate of the reputation system applied in this study is 90.9%. Compared with other Reputation System studies, this study not only extract features from DNS A-Type but also extract features from DNS NS-Type. The experiment results show the Error Rate of the new features from DNS NS-Type is only 19.03%.

Because of the convenience of the Internet, we rely closely on the Internet to do information searching and sharing, forum discussion, and online services. However, most of the websites we visit are developed by people with limited security knowledge, and this condition results in many vulnerabilities in web applications. Unfortunately, hackers have successfully taken advantage of these vulnerabilities to inject malicious JavaScript into compromised web pages to trigger drive-by download attacks. Based on our long time observation of malicious web pages, malicious web pages have unusual behavior for evading detection which makes malicious web pages different form normal ones. Therefore, we propose a client-side malicious web page detection mechanism named Web Page Checker (WPC) which is based on anomaly behavior tracing and analyzing to identify malicious web pages. The experimental results show that our method can identify malicious web pages and alarm the website visitors efficiently.

In recent years, people using information technology more to meet their demand for entertainment. For example, on-line game, MP3, on-line TV, movies and so on, which are belong such technology. The increasing of this demand is accompanied the growth of motivation and behavior of piracy. This study focused on recognize and decision pattern of behavior that downloading unauthorized movies, and tried to join the emotion impact, and, understanding college students¡¦ intention of downloading. The research model of this study based on triangle interaction from Social Cognitive Theory (SCT) and its core ¢w Self-efficacy, and developing questionnaire from literature review. The questionnaire measuring the social cognize and personal belief about the behavior which downloading unauthorized movies, and make up an movie with text and post, in order to engagement into the situation, and measuring the impact of intention. The results showed that the research model based on SCT will explain the detail of motivations and decision making about the intention to illegal downloading of common college students, and verified that emotion have the impact in decision making process. According to result, we recommend the irrational factor to research about piracy. For practice, we recommend the preventive of piracy will not only by viewpoint of ¡§crime¡¨ but also by investigate the motivation of piracy.

This thesis comparing broadband systems HomePlug and DS2 PLC technology (Power Line Communications). PLC is a technology for transmitting data over electrical power distribution network. The theoretical part consists of describing a system for broadband data communication over high-tension lines, the selection criteria, a description of DS2 and HomePlug (variants of chips, version, network architecture, elements). There are also described modulation techniques, interference, standards, standard ISO 50065 and access methods. The practical part consists of laboratory measurements with both systems. For the testing were used DS2 modems from the company Defidev and HomePlug modems from AirLive. These are then compared according to selected criteria.

Made available in DSpace on 2015-05-14T12:36:41Z (GMT). No. of bitstreams: 1 arquivototal.pdf: 13060370 bytes, checksum: d278616bda56ec354853e6497ba88f41 (MD5) Previous issue date: 2012-08-31 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The arrival of Digital TV has brought the possibility to broadcasters create interactive programs. For this, applications should be sent to the TV station via the standard DSMCC carousel. This standard enables data to be sent cyclically, so that any time you turn on the TV, it can receive all data transmitted. However, the way each interactive application will be available on the carousel has an impact on the users waiting time. The carousel can be modified to prioritize some applications, and so give more satisfaction to most users and also increase the profits of the station. It is not been defined yet a model of how to handle the priority of applications. Current work suggests an innovative business model, seeking to satisfy users, the broadcaster and the contractor.With the priorities of the applications, a new problem arises, termed here as the Download Time Variability Problem (DTVP). It defines the way that the carousel should be created to minimize the users waiting times. This is a difficult problem, which makes the use of exact techniques unapplicable for large instances. The paper proposes the use of GRASP and ILS metaheuristics to solve the problem. / A chegada da TV Digital trouxe consigo a possibilidade de criação de programas interativos por parte das emissoras. Para isso, aplicativos para TV devem ser enviados pela emissora através do padrão Carrossel DSM-CC. Esse padrão permite que os dados sejam enviados de forma cíclica, a fim de que a qualquer momento que o usuário ligue a TV, o mesmo possa receber todos os dados transmitidos. Porém, a forma com que cada aplicativo interativo vai estar disponível no carrossel tem um impacto no tempo de espera do usuário. O carrossel pode ser modificado de forma a priorizar algumas aplicações, e assim dar maior satisfação a maioria dos usuários e também aumentar o lucro da emissora. Ainda não existe um modelo definido de como tratar a prioridade das aplicações. O trabalho corrente sugere um modelo de negócio inovador, buscando satisfazer os usuários, a emissora e a empresa contratante. Com as prioridades das aplicações, surge um novo problema, denominado neste trabalho como o Problema da Variabilidade do Tempo de Download (PVTD). Ele trata da forma com que o carrossel deve ser gerado para minimizar o atraso no download das aplicações. Isso é um problema difícil, o que inviabiliza a utilização de técnicas exatas para grandes instâncias. O trabalho propõe a utilização das metaheurísticas GRASP e ILS para solucionar o problema.

L'incroyable développement du World Wide Web a permis la création de nouveaux métiers, services, ainsi que de nouveaux moyens de partage de connaissance. Le web attire aussi des malfaiteurs, qui le considèrent comme un moyen pour gagner de l'argent en exploitant les services et la propriété d'autrui. Cette thèse propose une étude des sites web compromis et malicieux sous plusieurs axes d'analyse. Même si les attaques web peuvent être de nature très compliquées, on peut quasiment toujours identifier quatre acteurs principaux dans chaque cas. Ceux sont les attaquants, les sites vulnérables hébergés par des fournisseurs d'hébergement, les utilisateurs (souvent victimes des attaques), et les sociétés de sécurité qui parcourent Internet à la recherche de sites web compromis à être bloqués. Dans cette thèse, nous analysons premièrement les attaques web du point de vue des hébergeurs, en montrant que, même si des outils gratuits permettent de détecter des signes simples de compromission, la majorité des hébergeurs échouent dans cette épreuve. Nous passons en suite à l'analyse des attaquants et des leurs motivations, en étudiant les attaques web collectés par des centaines de sites web vulnérables. Ensuite, nous étudions le comportement de milliers de victimes d'attaques web, en analysant leurs habitudes pendant la navigation, pour estimer s'il est possible de créer des "profils de risque", de façon similaire à ce que les compagnies d'assurance font aujourd'hui. Enfin, nous adoptons le point de vue des sociétés de sécurité, en proposant une solution efficace pour la détection d'attaques web convoyées par sites web compromis / The incredible growth of the World Wide Web has allowed society to create new jobs, marketplaces, as well as new ways of sharing information and money. Unfortunately, however, the web also attracts miscreants who see it as a means of making money by abusing services and other people's property. In this dissertation, we perform a multidimensional analysis of attacks involving malicious or compromised websites, by observing that, while web attacks can be very complex in nature, they generally involve four main actors. These are the attackers, the vulnerable websites hosted on the premises of hosting providers, the web users who end up being victims of attacks, and the security companies who scan the Internet trying to block malicious or compromised websites. In particular, we first analyze web attacks from a hosting provider's point of view, showing that, while simple and free security measures should allow to detect simple signs of compromise on customers' websites, most hosting providers fail to do so. Second, we switch our point of view on the attackers, by studying their modus operandi and their goals in a distributed experiment involving the collection of attacks performed against hundreds of vulnerable web sites. Third, we observe the behavior of victims of web attacks, based on the analysis of their browsing habits. This allows us to understand if it would be feasible to build risk profiles for web users, similarly to what insurance companies do. Finally, we adopt the point of view of security companies and focus on finding an efficient solution to detecting web attacks that spread on compromised websites, and infect thousands of web users every day

Made available in DSpace on 2015-03-05T13:58:26Z (GMT). No. of bitstreams: 0 Previous issue date: 13 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Apesar de ser uma das principais aplicações da Internet na atualidade, o compartilhamento de arquivos P2P tem sido fortemente prejudicado por ataques de poluição de conteúdo. Esta dissertação propõe e analisa uma classe de métodos de contenção de poluição cujo princípio básico é a limitação do número instantâneo de downloads de acordo com a reputação de versões. Inicialmente, o método é proposto e avaliado em termos de um ambiente idealizado, mostrando sua eficiência na contenção de poluição e baixa sobrecarga induzida quando o título não é poluído. A seguir, valendo-se de modelos clássicos para projeto de redes P2P, são propostos e comparados métodos de contenção distribuída / Despite currently one of the main Internet applications, P2P file sharing has been hampered by content pollution attacks. This work proposes and analyzes a class of contention methods to reduce the dissemination of polluted content whose basic principle is to limit the amount of instantaneous downloads according to its reputation. The method is firstly proposed and evaluated in terms of an idealized environment. The evaluation shows the eficiency of the contention method and the low overhead induced when the content is not polluted. Then, inspired by classic P2P designs, we propose and compare distributed contention methods

Made available in DSpace on 2015-03-05T13:58:27Z (GMT). No. of bitstreams: 0 Previous issue date: 16 / Bolsa para curso e programa de Pós Graduação / BitTorrent é a tecnologia de compartilhamento de arquivos mais popular atualmente na Internet e responsável por fração significativa do tráfego nela existente. Considerando sua importância e adoção em larga escala, a arquitetura BitTorrent precisa ser robusta e resistente a pares maliciosos. Esta dissertação constitui a primeira investigação em termos de vulnerabilidades do BitTorrent, apresentando quatro contribuições principais: (a) auxilia no entendimento do BitTorrent; (b) identifica vulnerabilidades e descreve ataques e contramedidas possíveis à arquitetura; (c) descreve um modelo de simulação discreto, que permite mapear o comportamento do protocolo BitTorrent; e (d) avalia, via simulação, o impacto de dois dos ataques identificados, Mentira de Peças e Eclipse. Os resultados mostram que BitTorrent é suscetível a ataques em que pares maliciosos mentem a posse de peças e tornam-nas mais raras, fazendo com que downloads em geral sejam atrasados em até 50%. Em ataques Eclipse, com uma proporção em torno de / BitTorrent is the most popular file sharing technology and associated with a significant fraction of the Internet traffic. Considering its importance and large scale adoption, the BitTorrent architecture should be robust and resistant to malicious peers. This dissertation is the first investigation in terms of vulnerabilities against BitTorrent architecture, providing four important contributions: (a) it helps to increase the understanding of the BitTorrent protocol; (b) it identifies vulnerabilities and describes feasible attacks and countermeasures to the BitTorrent architecture; (c) it presents a discrete event simulation model which maps the behaviour of the protocol; and (d) it evaluates, through simulation, the impact of two proposed attacks, namely Piece Lying and Eclipse. Results show what BitTorrent is vulnerable to cheating peers that lie about having pieces, in order to make them rarer, causing an increase of about 50% in downloading times. Eclipse attacks can cause even more damage, as analysis

The superior reconfigurability of software defined radio mobile devices has made it one of the most promising technology on the wireless network and in the mobile communication industry. The evolution from a static and rigid system to a highly dynamic environment, which offers many advantages over current systems, has been made possible thanks to the concepts of programmability and reconfigurability introduced by the software defined radio technology and the higher level of flexibility and openness of this technology's devices. Clearly, the software defined radio mobile device's flexibility is a great advantage since the customer is able to use the same device in different parts of the world, with different wireless technologies. Despite the advantages, there are still issues to be discussed regarding security. According to the Software Defined Radio Forum some of the concerns are the radio configuration download, storage and installation, user's privacy, and cloning. To address the SDR Forum concerns a raud-prevention framework is proposed. The framework is composed by new pieces of hardware, new modules and new protocols that together greatly enhance the overall security of software defined radio mobile devices and this new highly dynamic environment. The framework offers security monitoring against malicious attacks and viruses that may affect the configuration data; protects sensitive information through the use of protected storage; creates and protects an identity for the system; employs a secure and efficient protocol for radio configuration download and update; and finally, establishes an anti-cloning scheme, which not only guarantees that no units can be cloned over the air but also elevates the level of difficulty to clone units if the attacker has physical access to those units. Even if cloned units exist, the anti-cloning scheme is able to identify them and deny any service.