How China Is Blocking Tor

TL;DR

This paper investigates China's censorship of the Tor network, analyzing its blocking mechanisms, hypothesizing its infrastructure design, and proposing countermeasures to improve evasion techniques.

Contribution

It provides insights into China's Tor blocking infrastructure and introduces potential countermeasures to enhance censorship evasion.

Findings

Analysis of China's Tor blocking mechanisms

Hypotheses on the infrastructure design

Proposed countermeasures for evasion

Abstract

Not only the free web is victim to China's excessive censorship, but also the Tor anonymity network: the Great Firewall of China prevents thousands of potential Tor users from accessing the network. In this paper, we investigate how the blocking mechanism is implemented, we conjecture how China's Tor blocking infrastructure is designed and we propose countermeasures. Our work bolsters the understanding of China's censorship capabilities and thus paves the way towards more effective evasion techniques.