On the gathering of Tor onion addresses

Exploring the Tor network requires acquiring onion addresses, which are crucial for accessing anonymous websites. However, the Tor protocol presents a challenge, as it lacks a standard method for finding these complex links composed of either 16 or 56 base32-coded characters and featuring the unique .oniontop-level domain. This study delves into the existing literature analyzing onion services and categorizes the various strategies employed to gather their addresses. The success of each approach is measured by the number of addresses obtained, while the relevancy of the work is evaluated by comparing the number of services uncovered to Tor's official count. The results indicate that the most used techniques are Tor crawling and repositories, whereas the most effective methods are relay injection, repositories, and Tor crawling. This paper also estimates the representativeness of literature collections, revealing that most past works explored a small portion of the Tor network. The study also uncovers the limitations of onion gathering and sheds light on the challenges for future research to provide more representative datasets for dark web exploration.(c) 2023 The Author(s). Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).

Automated summary

This study explores methods for acquiring onion network addresses and analyzes various strategies, evaluating their effectiveness and relevance. The results indicate that Tor crawling and repositories are the most commonly used methods, while relay injection, repositories, and Tor crawling are the most effective approaches. The study also reveals that previous research only explored a small portion of the Tor network and highlights the challenges for future studies in providing more representative datasets for dark web exploration.