<p>Online Social Network (OSN) services such as Facebook and Google+ are fun and useful. Hundreds of millions of users rely on these services and third-party applications to process and share personal data such as friends lists, photos, and geographic location histories. The primary drawback of today's popular OSNs is that users must fully trust a centralized service provider to properly handle their data.</p><p>This dissertation explores the feasibility of building feature-rich, privacy-preserving OSNs by shifting the bases for trust away from centralized service providers and third-party application developers and toward infrastructure providers and OSN users themselves.</p><p>We propose limiting the trust users place in service providers through two decentralized OSNs: Vis-a-Vis and Confidant. In Vis-a-Vis, privacy-sensitive data is only accessed by user-controlled code executing on ``infrastructure as a service" platforms such as EC2. In Confidant this data may only be accessed by code running on desktop PCs controlled by a user's close friends. To reduce</p><p>the risks posed by third-party OSN applications, we also developed a Multi-User Taint Tracker (MUTT). MUTT is a secure ``platform as a service" that ensures that third-party applications adhere to access policies defined by service providers and users. </p><p>Vis-a-Vis is a decentralized framework for location-based OSN services based on the</p><p>privacy-preserving notion of a Virtual Individual Server (VIS). A VIS is a personal virtual machine running within a paid compute utility. In Vis-a-Vis, a person stores her data on her own VIS, which arbitrates access to that data by others. VISs self-organize into overlay networks corresponding to social groups with whom their owners wish to share location information. Vis-a-Vis uses distributed location trees to provide efficient and scalable operations for creating, joining, leaving, searching, and publishing location data to these groups.</p><p>Confidant is a decentralized OSN platform designed to support a scalable application framework for OSN data without compromising users' privacy. Confidant replicates a user's data on servers controlled by her friends. Because data is stored on trusted servers, Confidant allows application code to run directly on these storage servers. To manage access-control policies under weakly-consistent replication, Confidant eliminates write conflicts through a lightweight cloud-based state manager and through a simple mechanism for updating the bindings between access policies and replicated data.</p><p>For securing risks from third-party OSN applications, this thesis proposes a Multi-User Taint Tracker (MUTT) -- a secure ``platform as a service'' designed to ensure that third-party applications adhere to access policies defined by service providers and users. Mutt's design is informed by a careful analysis of 170 Facebook apps, which allows us to characterize the requirements and risks posed by several classes of apps. Our MUTT prototype has been integrated into the AppScale cloud system, and experiments show that the additional data-confidentiality guarantees of running an app on MUTT come at a reasonable performance cost.</p> / Dissertation

This thesis was submitted to the faculty of Innovation, Design and Technology, IDT, at Mälardalen university in Västerås, Sweden as a partial fulfillment of the requirements to obtain the M.Sc. in computer science, specializing in embedded systems. The work presented was carried out in the months January to June in 2014 partially in Volvo Construction Equipment, Volvo CE, Eskilstuna, and partially at Mälardalen university in Västerås. Federated Resilient Embedded Systems Technology for AUTOSAR, FRESTA, is a collaborative project between Volvo and the Swedish Institute of Computer Science, SICS, that aims to make it possible to add third party applications to vehicle’s computer systems without compromising system security and robustness. The mechanism is developed by SICS for AUTOSAR, AUTomotive Open System ARchitecture, an open standardized automotive software architecture for vehicles. The following report documents the efforts to study and port the FRESTA mechanism to the Volvo CE platform, and develop a Java application to test the porting. The investigation will aspire to determine if it is feasible to introduce Java based third party applications to resource constrained embedded systems, without causing a deterioration in the predictability and security of the system. / Avhandlingen lades fram för fakulteten för innovation, design och teknik, IDT, vid Mälardalens högskola i Västerås som en del av kraven för att erhålla M.Sc. i datavetenskap med inriktning mot inbyggda system. Arbetet genomfördes under månaderna januari till juni 2014 delvis i Volvo Construction Equipment, Volvo CE, Eskilstuna, och delvis vid Mälardalens högskola i Västerås. Federated Resilient Embedded Systems Technology for AUTOSAR, FRESTA, är ett samarbetsprojekt mellan Volvo och Svenska Institutet för datavetenskap, SICS, som syftar till att göra det möjligt att lägga tredjepartsapplikationer till fordonets datorsystem utan att äventyra systemets säkerhet och robusthet. Mekanismen är utvecklat av SICS för AUTOSAR, Automotive Open System Architecture, en öppen standardiserad fordons programvaruarkitektur för fordon. Följande rapport dokumenterar arbetet med att studera Fresta mekanismen till Volvo CE-plattformen, och utveckla ett Java-program för att testa portning. Undersökningen kommer att sträva efter att avgöra om det är genomförbart att införa en Java-baserad tredje part för att resursbegränsa inbyggda system, utan att orsaka en försämring av förutsägbarhet och säkerhet i systemet.

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(in English): The diploma thesis deals with yet unprocessed complex issue of Twitterverse with a focus on community Twitter and third party applications. The thesis is mapping origin and development of Twitter and the related phenomenon Twitterverse using qualitative research methods case study. The work should contribute to a better and more detailed understanding of this issue for the general reader.

(in English): The diploma thesis deals with yet in czech language unprocessed complex issue of Twitterverse with a focus on community Twitter and third party applications. The thesis is mapping origin and development of Twitter and the related phenomenon Twitterverse using quantative research methods and case study. The work should contribute to a better and more detailed understanding of this issue.