Anonymity, Privacy and Hidden Services: Improving censorship-resistant publishing

The request for on-line privacy is rapidly increasing. More and more Internet users realize that information about their on-line activities is highly valuable information for commercial companies and open for potential abuse. Information about who communicates with whom, and who accesses which services, is already used to improve on-line services, e.g. by serving more relevant on-line advertisements which many appreciate. But the problem of letting large commercial companies know your entire surfing history does not seem to be of major concern to the average Internet user. Future services may look into how to prevent this type of information leakage, but this will not help the users of today. In addition, anonymous publication of information, e.g. by dissidents and whistle-blowers, is made nearly impossible for today’s Internet users. There exists a need for censorship-resistant Internet services, where anonymous publishing of information can be made. These types of services are already starting to appear. They are combined with anonymizing technologies, and designed to be attack-resistant, accessible from anywhere, have a hidden physical location, and therefore they will be more censorship-resistant. The overall goal of the research work was to address vulnerabilities in, and to develop new or enhance existing anonymizing network technologies and censorship-resistant services. This thesis presents both analyses and new principles to enhance the anonymizing technology existing today. The first phase of the research work consisted of an analysis of traffic flow confidentiality in a future military network setting, and an analysis of how to securely anonymize traffic data logs at high-speed interconnections. The thesis presents a new method for securing these logs by creating transaction specific pseudonyms without increasing the amount of logged data. The thesis also presents solutions to allow some elements of the traffic data to be used for statistical analysis and therefore be available for search, while