HLS Team Shows Chinese Web Filtering Widespread

Ground breaking research by a team from the Harvard Law School (HLS) has shown for the first time the extent to which the Chinese government filters Internet websites within the country.

Although rumors of censorship have abounded for years, the announcement by HLS Professor Jonathan Zittrain and first-year HLS student Benjamin G. Edelman ’02 shows the censorship is more advanced and widespread than earlier believed.

After conducting an extensive study of Internet filtering in countries world-wide, the two developed a program that determined and confirmed that Google and similar search engines were inaccessible from testing locations throughout China.

“The Chinese government has started moving beyond the crude blocking of entire Web sites,” said Edelman, who has researched restricted web access in China since August at HLS’ Berkman Center of Internet and Society.

“The government now appears to have started deploying a more focused and granular filtering system,” he said.

Although the extent and nature of China’s tightened controls is difficult to determine, the so-called “great firewall” blocks access to Chinese citizens who try to access or search for “controversial” or anti-government material on the web—blocking searches for the spiritual group ‘Falun Gong,’ for instance, a group that is critical of the government.

In developing their program, which is called the Real-time Testing System, Edelman and Zittrain, who is Berkman professor of entrepreneurial legal studies, connected to dozens of networks in China to simulate the network access experienced by ordinary users in Beijing.

To broaden the number and types of URLs tested, the two also created a web page to determine the accessibility of given sites in China.

“After a user gives the [system] a web page to test, the system connects to a device in China and attempts to retrieve the specified URL,” Edelman said. “It tracks the success or failure of the request, and it promptly tells the user whether the page could be retrieved as expected.”

Through such methods, the two confirmed that Google, which had been blocked by the government earlier this September, was now accessible in China but subject to censorship of certain controversial material.

According to Zittrain, the Real-time Testing System provides a valuable way to determine the extent of filtering and the “importance of filtering relative to China’s political leadership.”

Edelman, who began his research on censorship in 2000 when the ACLU asked him to help them challenge federal mandates for filtering software in libraries and public schools, considers censorship in China an international concern.

“Filtering is seemingly inconsistent with the UN’s Universal Declaration of Human Rights,” he said. “It also [indicates] that the Internet may be an instrument of censorship, political restrictions, discipline or other state control. In this context, carefully documenting the specific details of the changes is arguably helpful to those who seek to study, analyze, and debate such policies.”