Discovering the Shady Corner of the Internet: The Acquisition, Use, and Social Impacts of the Tor Anonymity Network


Student thesis: Doctoral Thesis

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Award date5 Aug 2022


The Onion Router (Tor) anonymity network is currently one of the most advanced and widely used anonymous communication technologies in the world. With specially designed communication protocols and network infrastructures, i.e., the voluntarily run relay networks for onion routing, the Tor network provided technically the highest level of anonymity for privacy-enhancing communication on the Internet. The anonymity affordance guaranteed by the technology has stimulated various unethical and anomalous online behavior, such as drug and weapon trafficking and child pornography. Therefore, it has attracted increasing attention from the public as well as law enforcement in recent decades. From a communication perspective, the Tor network also provides a window to observe how people interact with each other under the highly anonymous settings in online communication.

The general objective of this dissertation is to explore a discovery journey for potential users of the Tor anonymity network. Derived from earlier studies on the Internet and personal computers, a chain process model of the interplay between the Tor network and human society is proposed as the central theoretical framework. Three studies were conducted on separately collected datasets to answer the three research questions in each step of the chain process model, i.e., 1) the acquisition process, 2) usage and 3) social impacts. Both computational methods, including social network analysis and text mining, and statistical methods, such as linear mixed-effects models, Cox’s proportional hazard models, and propensity score matching, are employed for data analysis. The first study is analyzed at the aggregate level (country as the unit of analysis), while the other two studies are analyzed at the individual level.

The first study examines the diffusion process of the Tor network around the world, with a particular focus on the knowledge accumulation process. Effectively employing the technology is not a trivial process and involves the following steps: 1) motivated by needs, 2) becoming aware of and learning the technology, and 3) realizing desired purposes by usage. Using country-level panel data, this study examines the knowledge accumulation process through which motivated users eventually employ Tor. The results suggest that Tor is often searched in less free countries for censorship circumvention, while it is employed for Dark Web activities in more free countries. There is also an indirect relationship between being aware of the technology and its usage through how-to knowledge accumulation. This study is the first attempt to understand the role of knowledge accumulation in the global usage of Tor. The findings provide insights into the worldwide concerns of online privacy and Dark Web regulation.

The second study focuses on the cryptomarket forums and examines the user behavior in the fully anonymous online communities, with comparison to a similar forum on the Surface Web. The Dark Web has created a technically anonymous environment for dubious economic activities and social interactions, yet users must administer their online behaviors to preserve social anonymity in the communities. This twisted social behavior may subsequently affect their continuous participation. We use a computational and comparative approach to look for unique social behaviors on the Dark Web and their effects on sustainable usage. Results show that the strength of social interactions is lower on the Dark Web than on the Surface Web, while the emotional valence is more positive on the Dark Web. Furthermore, strong social interactions and negative feedback tend to impede prolonged usage of the Dark Web, contrasting with the promotion of user continuance on the Surface Web. The findings suggest that the Dark Web users, who usually bear a clear task purpose, show benevolence to peers through restrained social activities, but the social connections to the community are tenuous.

The third study examines the social impacts of using the Tor network. As an emerging technology, Tor has been widely adopted across the world for various purposes. However, it remains unknown about the potential social consequences of using this technology. This study is intended to fill this research gap through a national survey in the United States with quota sampling on age and gender. Propensity score matching is used to estimate the average treatment effect of using the Tor network. Results show that people who have used the Tor network tend to be more likely to believe in misinformation related to COVID-19 as well as presidential candidates in the 2020 U.S. Presidential Election. Further, the users of the Tor network are less likely to take preventive measures during the COVID-19 pandemic. However, there is no significant relationship between the use of the Tor network and voting behavior during the 2020 U.S. Presidential Election. Overall, the study makes the first attempt to examine the social consequences of the use of the Tor network in a causal inference approach. The findings demonstrate that the use of the Tor network could lead to significant social consequences, particularly in the belief of misinformation related to public health and political issues. The study may inspire more future works on the social impacts of anonymity-granting technologies.

Finally, all the research findings in the three studies are summarized in the last chapter. Though there are some limitations, the dissertation has made the first attempt to tackle research questions around the Tor anonymity network from the perspective of communication studies. Existing literature on Tor anonymity lacks empirical and quantitative examinations from the theoretical perspectives of communication research. This dissertation fills the research gap. All the research findings are coherently organized under the theoretical framework of diffusion, use, and social impact of new media technology. Finally, both theoretical and social implications of the three studies are discussed. Future directions are outlined for more explorations and extensive studies.