Behind the blocking on Google

Several Western media recently reported that Google was blocked again in China. Financial Times reported, “users in many Chinese cities have been able to access Google.com only intermittently in recent days”. I have confirmed this with my friends in China, particularly in Beijing, Shandong and Shanghai. In addition, it was early reported that Microsoft's MSN Messenger Service and Passport service recently had the similar problems in China, too.

According to the symptoms of recent accessibility issues of Google.com and MSN Messenger Service in China, I reasonably speculate that China might be experimenting some new means or technology to intercept the sensitive information that possibly offends the government, though its current system, known as the Great Firewall, has been already reported as the most advanced online censorship system in the world.

I presume that the system under experiment might NOT be only to simply terminate the connections to forbidden websites or content-sensitive pages, but also to try:

• unknowingly redirecting web requests (with URL parameters) initially targeting forbidden sites to other sites under control or well filtered (such as the eunuch version of Google — Google.cn), and
• unwittingly prying private IM (Instant Messaging) communications, especially those via MSN Messenger Service and QQ service.

The recent anniversary of June 4th Incident would be a good chance to test, troubleshoot and evaluate the new system in a real environment, including the real contexts, real keywords and real network traffic. This was probably why accessing Google or MSN was intermittent in China in recent days.

I think the main technical challenges in the censorship would be:

• an appropriate and more efficient algorithm to correctly recognize the banned keywords and their variants based on the contexts captured from web requests, and
• a more efficient mechanism to reduce inevitable bandwidth usage and delay at the checkpoints where connect China's internal networks to the backbone of the Internet.

Briefly, one aspect would be filtering algorithm, another would be traffic control.

Anyway, I believe that till now the most efficient way in the game would still be to simply block the IP addresses of the forbidden sites, especially those providing audio/video streams. Hence, it is not doubted that China is currently maintaining a large blacklist for the unwelcome and controversial sites.

Such a blacklist would have been converted to the ACL (Access Control List) items and then deployed to the routers connecting to the Internet backbone, which would also unavoidably and significantly decrease the network performance of accessing the Internet from China because the ACLs have to be executed serially.

It is obvious that the new kind of online censorship would consume more network bandwidth and cause more bottlenecks, which would certainly lead to more delays in end-to-end communications from/to every Internet user in China. Of course, the related system would also need a more powerful hardware platform and more fast backbone bandwidth.

This sounds like a paradox, except the fact of wasting money and human resources. No wonder it is a "perfect" practice to “represent the developmental requirement of China's advanced productive force”, the first demands of the well-known mission statement “Three Representatives” put forward by the party and the government.

In a few words, I would speculate that the recent blocking on Google would be the prelude of next round of large scale censorship in China, which would probably be carried out in less than 10 months even half a year.

The related news:

BBC: China 'blocks' main Google site
Earth Times: Google founder admits the company compromised in China
FairFax Digital: We were evil, Google founder admits
Financial Times: Beijing's censors accused of disrupting Google.com
InterFax China: Hotmail and Windows Live Mail widely inaccessible in mainland China
P2P Net: Hotmail problems in China
PC Advisor UK: Hotmail problems persist in China
The Australian: Google's regret on Great Firewall
Wired News: China Tightens Grip on Web