Shedding Light on the Dark Corners of the Internet: A Survey of Tor Research

TL;DR

This survey comprehensively reviews 26 years of research on the Tor network, highlighting key focus areas like security, anonymity, and path selection, and analyzing research methodologies and experimental setups.

Contribution

It provides a detailed classification and quantitative analysis of past Tor research, identifying trends, common topics, and methodological approaches.

Findings

Most research focuses on de-anonymization and breaching strategies.

Path selection algorithms are a significant area of study.

Experimental studies mainly use private testbeds or custom simulators.

Abstract

Anonymity services have seen high growth rates with increased usage in the past few years. Among various services, Tor is one of the most popular peer-to-peer anonymizing service. In this survey paper, we summarize, analyze, classify and quantify 26 years of research on the Tor network. Our research shows that `security' and `anonymity' are the most frequent keywords associated with Tor research studies. Quantitative analysis shows that the majority of research studies on Tor focus on `deanonymization' the design of a breaching strategy. The second most frequent topic is analysis of path selection algorithms to select more resilient paths. Analysis shows that the majority of experimental studies derived their results by deploying private testbeds while others performed simulations by developing custom simulators. No consistent parameters have been used for Tor performance analysis. The majority of authors performed throughput and latency analysis.