Resumen de The great firewall of China: how it blocks Tor and why it is hard to pinpoint
Philipp Winter, Jedidiah Crandall
Internet censorship is no longer a phenomenon limited to countries with a weak human rights record—the Western world is beginning to embrace the idea. This development leads to a fundamental research question: how can we know where the roadblocks are on the Internet and the details of how they work? In this article, we use the “Great Firewall of China” (GFC) to illustrate how complex of a problem it can be to find the network filtering devices, and how sophisticated the filtering itself can be when directed at an advanced target such as the Tor anonymity network.
The GFC is only a small part of the legal, regulatory, and technical mechanisms China has put in place for Internet censorship [6], but it is an important part because it helps to separate China’s Internet from the Internet of the rest of the world. Without this, domestic control of Internet content would be moot because Chinese Internet users would simply seek out foreign Web sites where content was not controlled.
After all, the GFC is capable of much more than just filtering keywords. In this article, we will focus on two aspects.
We will first show the shortcomings in the current research literature that make it difficult to narrow down where Internet filtering occurs within China’s Internet using Internet measurements.
In the second part of this article, we will show how the GFC is blocking the Tor anonymity network. Despite being originally designed as a low-latency anonymity network, Tor is increasingly used as a censorship circumvention tool.
