Suchergebnisse

As a consequence of the recent debate about restrictions in the access to content on the Internet, a strong motivation has arisen for censorship monitoring: an independent, publicly available and global watch on Internet censorship activities is a necessary goal to be pursued in order to guard citizens' right of access to information. Several techniques to enforce censorship on the Internet are known in literature, differing in terms of transparency towards the user, selectivity in blocking specific resources or whole groups of services, collateral effects outside the administrative borders of their intended application. Monitoring censorship is also complicated by the dynamic nature of multiple aspects of this phenomenon, the number and diversity of resources targeted by censorship and its global scale. In the present Thesis an analysis of literature on internet censorship and available solutions for censorship detection has been performed, characterizing censorship enforcement techniques and censorship detection techniques and tools. The available platforms and tools for censorship detection have been found falling short of providing a comprehensive monitoring platform able to manage a diverse set of measurement vantage points and a reporting interface continuously updated with the results of automated censorship analysis. The candidate proposes a design of such a platform, UBICA, along with a prototypical implementation whose effectiveness has been experimentally validated in global monitoring campaigns. The results of the validation are discussed, confirming the effectiveness of the proposed design and suggesting future enhancements and research.

Part 4: Security ; International audience ; Censorship is becoming increasingly pervasive on the Internet, with the Open Net Initiative reporting nearly 50 countries practicing some form of censorship. Previous work has reported the existence of many forms of Internet censorship (e.g., DNS tampering, packet filtering, connection reset, content filtering), each of which may be composed to build a more comprehensive censorship system. Automated monitoring of censorship represents an important and challenging research problem, due to the continually evolving nature of the content that is censored and the means by which censorship is implemented. UBICA, User-based Internet Censorship Analysis, is a platform we implemented to solve this task leveraging crowdsourced data collection. By adopting an integrated and multi-step analysis, UBICA provides simple but effective means of revealing censorship events over time. UBICA has revealed the effect of several censorship techniques including DNS tampering and content filtering. Using UBICA, we demonstrate evidence of censorship in several selected countries (Italy, Pakistan, and South Korea), for which we obtained help from local users and manually validated the automated analysis.