As the world marks the 25th anniversary of the Tiananmen Square massacre, an anonymous group fighting for Internet freedom in China has struck another blow against the Great Firewall that censors the Chinese Web.

On Monday, two days before the 25th anniversary of the 1989 protests in which unnumbered demonstrators were killed, the digital activism group GreatFire succeeded in unlocking Google search for Chinese citizens.

The anonymous group did it by using a variation of a successful tactic they've employed in the past to defeat Chinese censors. The group relies on the concept of "collateral freedom," in which they host content that Chinese censors find objectionable on servers that the government cannot afford to shut down.

In this case, GreatFire created a mirror version of Google search and hosted it on Amazon Web Services, using a subpath of Amazon and Google's domains to support access. Buy using Amazon as the host, it is theoretically impossible (at least for the time being) for the government to shut down the GreatFire version of Google without shutting down Amazon. And so far, GreatFire has been correct in assuming that the government is not willing to shut down Amazon in China because of the impact it would have on business.

GreatFire has used a similar method to allow Chinese Internet users unfettered access to versions of the Wall Street Journal and Reuters websites. In April, the group also launched an Android app that allows people to see uncensored post from Sina Weibo, a Chinese version of Twitter.

The functionality of this unblocked version of Google was tested by Tech in Asia, which found the site accessible from the Chinese mainland. They posted a screengrab of search results for "Tiananmen Incident 1989," a search that would normally be blocked.

Screengrab by Tech in Asia

According to Tech in Asia, Google services aren't completely blocked in China, but they are tightly controlled. Normally, when one searches for the Tiananmen massacre in China, they get a "no data received message." As the 25th anniversary of the incident approached, censors ratcheted things up even more. According to GreatFire, Sina Weibo searches for the term "today" were blocked starting on June 3.

Though the URL for GreatFire's Google mirror site is not "human friendly," GreatFire hopes that in time it will become indexed in search engines making it more widely available to users.

The worldwide attention being paid to the anniversary of the Tiananmen protests have caused the Chinese government to take dramatic steps to control information. The day before the anniversary, the government reportedly blocked Google altogether.

Image by Michael Mandiberg/Flickr (CC BY-SA 2.0)