Privacy Preserving Cryptographic Protocols for Secure Heterogeneous Networks

Disertační práce se zabývá kryptografickými protokoly poskytující ochranu soukromí, které jsou určeny pro zabezpečení komunikačních a informačních systémů tvořících heterogenní sítě. Práce se zaměřuje především na možnosti využití nekonvenčních kryptografických prostředků, které poskytují rozšířené bezpečnostní požadavky, jako je například ochrana soukromí uživatelů komunikačního systému. V práci je stanovena výpočetní náročnost kryptografických a matematických primitiv na různých zařízeních, které se podílí na zabezpečení heterogenní sítě. Hlavní cíle práce se zaměřují na návrh pokročilých kryptografických protokolů poskytujících ochranu soukromí. V práci jsou navrženy celkově tři protokoly, které využívají skupinových podpisů založených na bilineárním párování pro zajištění ochrany soukromí uživatelů. Tyto navržené protokoly zajišťují ochranu soukromí a nepopiratelnost po celou dobu datové komunikace spolu s autentizací a integritou přenášených zpráv. Pro navýšení výkonnosti navržených protokolů je využito optimalizačních technik, např. dávkového ověřování, tak aby protokoly byly praktické i pro heterogenní sítě.The dissertation thesis deals with privacy-preserving cryptographic protocols for secure communication and information systems forming heterogeneous networks. The thesis focuses on the possibilities of using non-conventional cryptographic primitives that provide enhanced security features, such as the protection of user privacy in communication systems. In the dissertation, the performance of cryptographic and mathematic primitives on various devices that participate in the security of heterogeneous networks is evaluated. The main objectives of the thesis focus on the design of advanced privacy-preserving cryptographic protocols. There are three designed protocols which use pairing-based group signatures to ensure user privacy. These proposals ensure the protection of user privacy together with the authentication, integrity and non-repudiation of transmitted messages during communication. The protocols employ the optimization techniques such as batch verification to increase their performance and become more practical in heterogeneous networks.

Literature, law, and learning: excursions from computer science

With the goal of identifying success factors for interdisciplinary collaboration, this paper describes three such collaborations by a computer scientist with: a digital culture researcher from a literary background; an IT law professor; and an education specialist with a background in modern languages. Success factors are discussed for each collaboration and four success factors are suggested:shared context between researchers; strong communication;shared context between disciplines; typology of collaboration

Privacy Unraveling Around Explicit HIV Status Disclosure Fields in the Online Geosocial Hookup App Grindr

mHealth applications ("apps") must be searched for and downloaded prior to use, creating a potential barrier to uptake. Integrating health interventions into existing online social environments removes this barrier. However, little is known about the effects of linking sensitive health information to existing online identities. Our qualitative analysis of online comments (n=192) explores the user views of an HIV intervention integrated into the geosocial hookup app Grindr. We find some HIV positive users report keeping their status private to reduce their stigma exposure, whilst others report publicly disclosing their status to avoid being stigmatised by others. Where users keep their status private, we find concerns that social assumptions may develop around these non-disclosures, creating a privacy unraveling effect which restricts disclosure choice. Using Peppet's four proposed limits to privacy unraveling, we develop a set of descriptive conceptual designs to explore the privacy respecting potential of these limits within this context and propose further research to address this privacy challenge

A unified ecological framework for studying effects of digital places on well-being

Social media has greatly expanded opportunities to study place and well-being through the availability of human expressions tagged with physical location. Such research often uses social media content to study how specific places in the offline world influence well-being without acknowledging that digital platforms (e.g., Twitter, Facebook, Youtube, Yelp) are designed in unique ways that structure certain types of interactions in online and offline worlds, which can influence place-making and well-being. To expand our understanding of the mechanisms that influence social media expressions about well-being, we describe an ecological framework of person-place interactions that asks, “at what broad levels of interaction with digital platforms and physical environments do effects on well-being manifest?” The person is at the centre of the ecological framework to recognize how people define and organize both digital and physical communities and interactions. The relevance of interactions in physical environments depends on the built and natural characteristics encountered across modes of activity (e.g., domestic, work, study). Here, social interactions are stratified into the meso-social (e.g., local social norms) and micro-social (e.g., personal conversations) levels. The relevance of interactions in digital platforms is contingent on specific hardware and software elements. Social interactions at the meso-social level include platform norms and passive use of social media, such as observing the expressions of others, whereas interactions at the micro-level include more active uses, like direct messaging. Digital platforms are accessed in a physical location, and physical locations are partly experienced through online interactions; therefore, interactions between these environments are also acknowledged. We conclude by discussing the strengths and limitations of applying the framework to studies of place and well-being

Linking geosocial sensing with the socio-demographic fabric of smart cities

Technological advances have enabled new sources of geoinformation, such as geosocial media, and have supported the propagation of the concept of smart cities. This paper argues that a city cannot be smart without citizens in the loop, and that a geosocial sensor might be one component to achieve that. First, we need to better understand which facets of urban life could be detected by a geosocial sensor, and how to calibrate it. This requires replicable studies that foster longitudinal and comparative research. Consequently, this paper examines the relationship between geosocial media content and socio-demographic census data for a global city, London, at two administrative levels. It aims for a transparent study design to encourage replication, using Term Frequency—Inverse Document Frequency of keywords, rule-based and word-embedding sentiment analysis, and local cluster analysis. The findings of limited links between geosocial media content and socio-demographic characteristics support earlier critiques on the utility of geosocial media for smart city planning purposes. The paper concludes that passive listening to publicly available geosocial media, in contrast to pro-active engagement with citizens, seems of limited use to understand and improve urban quality of life

Gay Data

Since its launch in 2009, the geosocial networking service Grindr has become an increasingly mainstream and prominent part of gay culture, both in the United States and globally. Mobile applications like Grindr give users the ability to quickly and easily share information about themselves (in the form of text, numbers, and pictures), and connect with each other in real time on the basis of geographic proximity. I argue that these services constitute an important site for examining how bodies, identities, and communities are translated into data, as well as how data becomes a tool for forming, understanding, and managing personal relationships. Throughout this work, I articulate a model of networked interactivity that conceptualizes self-expression as an act determined by three sometimes overlapping, sometimes conflicting sets of affordances and constraints: (1) technocommercial structures of software and business; (2) cultural and subcultural norms, mores, histories, and standards of acceptable and expected conduct; and (3) sociopolitical tendencies that appear to be (but in fact are not) fixed technocommercial structures. In these discussions, Grindr serves both as a model of processes that apply to social networking more generally, as well as a particular study into how networked interactivity is complicated by the histories and particularities of Western gay culture. Over the course of this dissertation, I suggest ways in which users, policymakers, and developers can productively recognize the liveness, vitality, and durability of personal information in the design, implementation, and use of gay-targeted social networking services. Specifically, I argue that through a focus on (1) open-ended structures of interface design, (2) clear and transparent articulations of service policies, and the rationales behind them, and (3) approaches to user information that promote data sovereignty, designers, developers, and advocates can work to make social networking services, including Grindr, safer and more representative of their users throughout their data’s lifecycle

Crowd-Sourcing the Smart City: Using Big Geosocial Media Metrics in Urban Governance

Using Big Data to better understand urban questions is an exciting field with challenging methodological and theoretical problems. It is also, however, potentially troubling when Big Data (particularly derived from social media) is applied uncritically to urban governance via the ideas and practices of “smart cities”. This essay reviews both the historical depth of central ideas within smart city governance —particular the idea that enough data/information/knowledge can solve society problems—but also the ways that the most recent version differs. Namely, that the motivations and ideological underpinning behind the goal of urban betterment is largely driven by technology advocates and neoliberalism rather than the strong social justice themes associated with earlier applications of data to cities. Geosocial media data and metrics derived from them can provide useful insight and policy direction. But one must be ever mindful that metrics don’t simply measure; in the process of deciding what is important and possible to measure, these data are simultaneously defining what cities are