Sharing our thoughts on the cat-and-mouse game

In this post, we share some of our thoughts on the cat-and-mouse game of censorship. Our views are based on our observations and reflections on both the censor and the anti-censorship community; we have also been deeply influenced by klzgrad, David Fifield, and many other anti-censorship developers and researchers.

In particular, we start with answering why censor always starts the massive blocking a few days or weeks before politically sensitive period of time in China; we then argue that, comparing to the anti-censorship community, a fundamental weakness of censor is its inflexibility. We further discuss how to exploit censor’s weaknesses to achieve better anti-censorship effect with limited resources.

Censor’s timing choice of new blocking techniques

As many long-time Internet censorship observers have noticed, Chinese censors always start using their new censorship weapons on a large scale a few days or weeks before a politically sensitive event. In fact, such timing choices are no coincident. So what are the specific reasons? We suspect there are at least three reasons, and we encourage everyone to share their thoughts on them.

1. First, it is an important political task for censors to ensure that they have sufficient control over public opinion and information flow, at least during politically sensitive time periods. This task is often described in official parlance as “protecting the cybersecurity during such-and-such event”.

2. Second, censors are willing to tolerate more collateral damage caused by false positives in detection during sensitive times. This nature provides new censorship weapons a more permissive trial-and-error environment when they are first put into use. Tschantz et al. analyze and summarize a large number of censorship incidents and find that “real censors tend to use vulnerabilities that produce underblocking but not overblocking” (see recommendation 5). And this tendency shifts slightly during politically sensitive times: censors become more tolerant of the collateral damage caused by false positives in detection in trade of a tighter social control. By deploying a new censorship weapon during such period of time, the censor’s mistake will be more tolerated even if the tool caused any overblocking accident due to bugs that were not tested out in the prior phases. klzgrad shares a similar view in this comment.

3. Finally, and most importantly, a often overlooked reason is the fact that the GFW is actually trying to compensate for and cover up its fundamental weakness of inflexibility. In this cat-and-mouse game, the censors know that they are simply no match for the anti-censorship community in terms of responsiveness and flexibility. If they started deploying their new secret weapon long before the sensitive period begins, the anti-censorship community will have more time to study it and find new ways to bypass censorship. At that point, if they can’t be flexible and fast enough to improve their censorship weapons, then their attempts to tighten their controls over the Internet during politically sensitive times will fall flat. David Fifield shared a similar point of view in this comment.

Censors have weaknesses

The censor’s lack of flexibility is dictated by the nature of itself and the problems it faces. Specifically, it is itself part of a large bureaucracy, which inevitably leads to inefficient internal operations and rigid behaviors. And yet the problem it faces is as complex as monitoring and censoring network traffic on a national scale. It is not hard to imagine that a new censorship weapon always has to go through the procedures of early-phase research, grants application, more formal scientific research, product development, debugging, surveying on real-world traffic, experimental deployment, and then the final nationwide large-scale deployment and use. The length of the process can take quite a long time.

One may be wondering if it indeed takes such a long time for the censor to deploy a censorship weapon. Let’s take this release as another experiment to observe how fast the censor and anti-censorship community can react. In particular, let’s see how long it takes the censors to block our released tool that has many weaknesses.

How to exploit censor weaknesses?

Exploiting the censor’s weakness, we came up with a few principles in hope they can make the anti-censorship efforts more effective.

1. Be more tolerant of imperfect circumvention solutions and do not give up on an imperfect circumvention solution too soon. As mentioned in the previous section, the fact that the GFW is less flexible than the anti-censorship community is often overlooked. And because of that, many circumvention solutions have been dismissed and killed prematurely simply because they “have weaknesses”. This is often because when anti-censorship developers and researchers envisioning themselves as censors, they tend to focus on the first step for censor – “pre-research” – and thinking that a circumvention solution would be easily blocked; however, they actually underestimated the long process of funding applications, formal scientific research, product development, debugging, surveying real-world traffic, experimental deployments, and finally, nationwide deployment, that the real censors have to face. In fact, if an anti-censorship developer spends an afternoon rolling out a new anti-censorship tool, but it takes the censor a large amount of time, energy, human, material and financial resources to block it in six months, we have to say this “imperfect” tool served as a great leverage.

2. Increase the diversity of censorship circumvention solutions by letting a thousand flowers bloom. In many people’s imagination, the GFW is a perfect censor because of its national-level resources; however, in reality, there are limited number of teams with the skills, ability, and resources to walk through all the procedures to make a censorship weapon from an idea to a real weapon deployed national-wide. Therefore, the more anti-censorship solutions the community can create, the less likely these limited resource censor teams will be able to block all tools in one go. And as long as there is one working circumvention solution left in one of these massive blocking event, the information is not disrupted completely.

3. Actively report new censorship events, promptly measure and understand new censorship techniques, and share the viable circumvention strategies with the community. Achieving this will require communication, effort, and cooperation between Chinese netizens, researchers, and developers. Encouragingly, we are now seeing more and more people joining this collaboration and working together as a collective.

4. Develop backup circumvention tools in advance. We have seen that the GFW makes up for its lack of flexibility by starting using its new secret weapons in large scale a few days before politically sensitive events. So can we use a similar strategy where we develop more backup plans in normal times, and then send them out just before sensitive times, like this release? This way, even if the technical staffs working for the GFW immediately spot any flaws in the new tool, and knew how to block the tool, it would still take them a long research and development cycle before actually being able to block it in real world.

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