Evolution of the Tor Network: An Empirical Analysis of Usage Patterns and Infrastructure
Chaitanya Rahalkar, Anushka Virgaonkar · 2025
The Tor network has been a significant part of the Internet for years. Tor was originally developed at the U.S. Naval Research Laboratory for anonymous online communication. From its early use for private browsing, it has expanded into use cases ranging from censorship circumvention to illicit marketplaces. In this paper, we perform an empirical analysis of how Tor’s usage patterns and infrastructure have evolved over time. We gather longitudinal data through our measurement scripts, prior research, and aggregated statistics provided by the Tor Metrics portal. Using this data, we analyze trends and identify events that caused fluctuations in various metrics: the number of Tor users, the prevalence of onion services, the population of Tor relays and bridges, etc. We examine notable censorship events and security incidents to understand their impact on Tor usage. Finally, we explore Tor’s location diversity and discuss how the distribution of relay bandwidth across geographies and autonomous systems can affect circuit selection and anonymity. Our findings provide an updated overview of the Tor network’s evolution and highlight ongoing challenges in maintaining its privacy and availability.