Le partage d'informations dans les systèmes de réseaux sociaux (SRS) suscite des inquiétudes concernant de possibles abus impactant la vie privée. La possibilité pour les utilisateurs de contrôler les informations qu'ils partagent avec le fournisseur de SRS et avec les autres utilisateurs peut être améliorée par la décentralisation des données personnelles et par une gestion appropriée des conflits entre politiques. Prenant son inspiration dans l'approche de décentralisation, la première contribution de cette thèse est la proposition de propriétés relevant de la conception du SRS et impactant la vie privée lorsqu'elles sont considérées par rapport à une gradation de la décentralisation. Ces propriétés ont été organises dans une grille d'analyse multicritères conçue pour analyser et comparer les SRS. L'application de la théorie des treillis à cette grille permet d'évaluer, de classifier et de visualiser différents SRS dans une hiérarchie partielle. Alors que la décentralisation résoudre des problèmes impliquant le fournisseur de SRS, les politiques de vie privée jouent un rôle majeur dans la protection contre les accès non autorisés par d'autres utilisateurs. La seconde contribution de cette thèse consiste en l'introduction du concept d'équité dans le contexte de la gestion des conflits entre politiques. Un algorithme conçu pour maintenir l'équité entre les utilisateurs de SRS est introduit pour résoudre les conflits pouvant survenir entre les politiques de plusieurs utilisateurs, évitant que certains puissent gagner un avantage sur d'autres. L'évaluation montre que l'approche introduite dans cette thèse conduit à de meilleurs résultats que les stratégies classiques de résolution de conflits, réduisant ainsi les iniquités existantes en termes d'application des politiques. / In Social Network Systems (SNSs), the sharing of information leads to many privacy concerns about potential abuses of personal information. Users’ control over information shared with the SNS provider and with other users could be improved in SNSs through the decentralization of personal data, and the proper management of policy conflicts. Inspired by the decentralization approach, the firrst contribution of this thesis is the proposal of SNS design properties relevant to privacy when considered along a gradation of decentralization. These properties are organized in a multi-criteria analysis grid, designed to analyze and compare SNSs. The application of a lattice structure on this grid allows to evaluate, classify and visualize different SNSs within a partial hierarchy. While decentralization solves issues involving the SNS provider, privacy policies play a leading role in the protection of unauthorized data access from other users. The second contribution of this thesis consists in the introduction of the concept of equity in the context of policy conflict management. An algorithm to maintain equity between users in SNSs is introduced to solve conflicts that may arise between the privacy policies of several users, avoiding that some users take advantage over others. The evaluation shows that the equity approach introduced in this thesis leads to better results than classical conflict resolution strategies, reducing existing inequities in terms of policy enforcement.

The prevalence of wireless networks and the convenience of mobile cameras enable many new video applications other than security and entertainment. From behavioral diagnosis to wellness monitoring, cameras are increasing used for observations in various educational and medical settings. Videos collected for such applications are considered protected health information under privacy laws in many countries. Visual privacy protection techniques, such as blurring or object removal, can be used to mitigate privacy concern, but they also obliterate important visual cues of affect and social behaviors that are crucial for the target applications. In this dissertation, we propose to balance the privacy protection and the utility of the data by preserving the privacy-insensitive information, such as pose and expression, which is useful in many applications involving visual understanding. The Intellectual Merits of the dissertation include a novel framework for visual privacy protection by manipulating facial image and body shape of individuals, which: (1) is able to conceal the identity of individuals; (2) provide a way to preserve the utility of the data, such as expression and pose information; (3) balance the utility of the data and capacity of the privacy protection. The Broader Impacts of the dissertation focus on the significance of privacy protection on visual data, and the inadequacy of current privacy enhancing technologies in preserving affect and behavioral attributes of the visual content, which are highly useful for behavior observation in educational and medical settings. This work in this dissertation represents one of the first attempts in achieving both goals simultaneously.

In the Master’s thesis were described privacy protection problems while using cloud technologies. Some of the problems can be solved with help of homomorphic encryption, data splitting or searchable encryption. These techniques were described and compared by provided security, privacy protection and efficiency. The data splitting technique was chosen and implemented in the C language. Afterwards a performance of the implemented solution was compared to AES encryption/decryption performance. An application for secured data storing in cloud was designed and implemented. This application is using the implemented data splitting technique and third-party application CloudCross. The designed application provides command line interface (CLI) and graphical user interface (GUI). GUI extends the capabilities of CLI with an ability to register cloud and with an autodetection of registered clouds. The process of uploading/downloading the data to/from cloud storage is transparent and it does not overload the user with technical details of used data splitting technique.

Le partage d'informations dans les systèmes de réseaux sociaux (SRS) suscite des inquiétudes concernant de possibles abus impactant la vie privée. La possibilité pour les utilisateurs de contrôler les informations qu'ils partagent avec le fournisseur de SRS et avec les autres utilisateurs peut être améliorée par la décentralisation des données personnelles et par une gestion appropriée des conflits entre politiques. Prenant son inspiration dans l'approche de décentralisation, la première contribution de cette thèse est la proposition de propriétés relevant de la conception du SRS et impactant la vie privée lorsqu'elles sont considérées par rapport à une gradation de la décentralisation. Ces propriétés ont été organises dans une grille d'analyse multicritères conçue pour analyser et comparer les SRS. L'application de la théorie des treillis à cette grille permet d'évaluer, de classifier et de visualiser différents SRS dans une hiérarchie partielle. Alors que la décentralisation résoudre des problèmes impliquant le fournisseur de SRS, les politiques de vie privée jouent un rôle majeur dans la protection contre les accès non autorisés par d'autres utilisateurs. La seconde contribution de cette thèse consiste en l'introduction du concept d'équité dans le contexte de la gestion des conflits entre politiques. Un algorithme conçu pour maintenir l'équité entre les utilisateurs de SRS est introduit pour résoudre les conflits pouvant survenir entre les politiques de plusieurs utilisateurs, évitant que certains puissent gagner un avantage sur d'autres. L'évaluation montre que l'approche introduite dans cette thèse conduit à de meilleurs résultats que les stratégies classiques de résolution de conflits, réduisant ainsi les iniquités existantes en termes d'application des politiques. / In Social Network Systems (SNSs), the sharing of information leads to many privacy concerns about potential abuses of personal information. Users’ control over information shared with the SNS provider and with other users could be improved in SNSs through the decentralization of personal data, and the proper management of policy conflicts. Inspired by the decentralization approach, the firrst contribution of this thesis is the proposal of SNS design properties relevant to privacy when considered along a gradation of decentralization. These properties are organized in a multi-criteria analysis grid, designed to analyze and compare SNSs. The application of a lattice structure on this grid allows to evaluate, classify and visualize different SNSs within a partial hierarchy. While decentralization solves issues involving the SNS provider, privacy policies play a leading role in the protection of unauthorized data access from other users. The second contribution of this thesis consists in the introduction of the concept of equity in the context of policy conflict management. An algorithm to maintain equity between users in SNSs is introduced to solve conflicts that may arise between the privacy policies of several users, avoiding that some users take advantage over others. The evaluation shows that the equity approach introduced in this thesis leads to better results than classical conflict resolution strategies, reducing existing inequities in terms of policy enforcement.

Submitted by Nadir Basilio (nadirsb@uninove.br) on 2016-05-09T18:32:43Z No. of bitstreams: 1 Caio Miachon Tenorio.pdf: 889460 bytes, checksum: e61ef24fc9d93ea5b4160d4ed53483d1 (MD5) / Made available in DSpace on 2016-05-09T18:32:43Z (GMT). No. of bitstreams: 1 Caio Miachon Tenorio.pdf: 889460 bytes, checksum: e61ef24fc9d93ea5b4160d4ed53483d1 (MD5) Previous issue date: 2013-11-12 / After the invention of the internet, new legal situations arising from this revolutionary technological advancement shown to be important for the legal world. The World Wide Web, however, has not only brought a lot of benefits, but also brought harmful effects. Privacy was one of the main victims of this technology. On the other hand, the protection on the web, has its technical peculiarities, limited to the architecture of a decentralized system, which requires specific technical knowledge of the legal system, as a way of getting a effectively protective measure in order to safeguard the privacy of the individual. The lack of internet regulations, combined with the legal practitioners´ lack of knowledge, including herein the Judiciary itself, results in an unfair practical application to the relations between companies and web users, which does not collaborate with social appeasement. The purpose of this project is to present a list of normative and legal guardianship able to protect and preserve privacy in the information society, outlining the responsibilities of the main internet service providers and hoping to contribute to a more balanced and innovative web. / Com o surgimento da internet, novas situações jurídicas advindas deste revolucionário avanço tecnológico revelaram-se importantes para o direito. A rede mundial de computadores, todavia, não trouxe apenas benefícios. A privacidade foi uma das principais vítimas desta tecnologia. A tutela na rede mundial de computadores tem suas peculiaridades técnicas, condicionadas à arquitetura de um sistema descentralizado, que demanda conhecimentos técnicos específicos do sistema jurídico, como forma de obter uma medida protetiva eficiente capaz de salvaguardar a privacidade do indivíduo. A falta de regulamentação da internet, aliada à falta de conhecimento dos profissionais do direito, incluindo-se aí o próprio Poder Judiciário, resultam, por vezes, na aplicação de um direito prático injusto às relações entre empresas e usuários da web, que em nada colaboram à pacificação social. O presente trabalho tem como intuito apresentar um rol de tutelas normativas e jurisdicionais aptas a proteger e preservar a privacidade de maneira eficiente no âmbito cibernético, delimitando as responsabilidades dos principais provedores de serviço de internet, na esperança de contribuir para uma web mais equilibrada e inovadora.

In the Master’s thesis were described privacy protection problems while using cloud technologies. Some of the problems can be solved with help of homomorphic encryption, data splitting or searchable encryption. These techniques were described and compared by provided security, privacy protection and efficiency. The data splitting technique was chosen and implemented in the C language. Afterwards a performance of the implemented solution was compared to AES encryption/decryption performance. An application for secured data storing in cloud was designed and implemented. This application is using the implemented data splitting technique and third-party application CloudCross. The designed application provides command line interface (CLI) and graphical user interface (GUI). GUI extends the capabilities of CLI with an ability to register cloud and with an autodetection of registered clouds. The process of uploading/downloading the data to/from cloud storage is transparent and it does not overload the user with technical details of used data splitting technique.

Tato práce analyzuje ochranu citlivých dat na mobilních zařízeních a představuje metodu pro ochranu těchto dat před možností úniku informaci ze zařízení. Ochrana se zaměřuje na využívání zařízení, jak pro osobní účely, tak i v pracovním prostředí. Koncept navrženého řešení je implementován ve formě prototypu. Model implementace je verifikován s modelem požadovaného chování. Součástí práce jsou experimenty s prototypem a experimenty zaměřené na verifikaci mezi danými modely.

Applications and services that take advantage of social data usually infer social relationships using information produced only within their own context, using a greatly simplified representation of users' social data. We propose to combine social information from multiple sources into a directed and weighted social multigraph in order to enable novel socially-aware applications and services. We present GeoS, a geo-social data management service which implements a representative set of social inferences and can run on a decentralized system. We demonstrate GeoS' potential for social applications on a collection of social data that combines collocation information and Facebook friendship declarations from 100 students. We demonstrate its performance by testing it both on PlanetLab and a LAN with a realistic workload for a 1000 node graph.

Recent trends in social network services (SNS) have taken the rates of personal information sharing, storage and processing to an unprecedented level, which yield both benefits and undesirable consequences for their users. SNS is being exploited by criminals to fraudulently obtain information from unsuspecting users. User’s awareness of privacy protection has been far left behind by the increasing and popularizing utilization of social network services (SNS), the privacy security problems will become one of the important factors influencing the healthy development of social network service industry. This study was designed to collect data and produce knowledge about the security awareness of WeChat users (i.e., randomly selected from all over China), their preferences and their experience of using WeChat while facing security issues as well as the perspectives of how people perceive a specific security problems, in order to find out what factors influence user's security awareness. In order to carefully conduct the research process and explain the empirical findings, seven principles of interpretive field research and protection motivation theory is adopted as core theoretical foundation. Participants were asked to provide information about and their personal views of questions from their different experience and value. Eight persons interviewed for our research and their responses confirmed our objectives of the study. As a result, six factors are indentified in related to WeChat user’s security awareness. PMT helps to explain and understand that how six indentified concepts influence behaviour intention and security awareness of user.

The primary aim of this dissertation thesis is to present a comprehensive analysis of the issue of personal data protection in the Czech Republic with regard to the regulation in the EU. The secondary goal of this work is to explore the historical genesis and material sources of the issue in question. The core information sources from which the thesis draws represent laws, judicial decisions, official documents and Czech/foreign expert literature. In order to achieve the objectives of the work, the methods that are generally applicable in the field of legal science were used. Therefore the method of description (including classification), analysis and synthesis is mostly applied. The dissertation consists of seven chapters. After a short introduction, it begins with a sociological treatise on the importance of the protection of personal data in the 21st century. Privacy is currently an important topic in the light of the rapid development of information and communication technologies which have been developing since the second half of the 20th century and burgeoned since the turn of the century. Technological innovations allow for the collection of personal data on a large scale. These privacy infringements can prove to be irreversible, hence the importance of this area of law. The personal data...