Researchers reverse-engineer Chinese streaming services to learn how they're censored

As live streaming appssurgein popularity in China, the companies profiting from the craze are pulling out all the stops to censor millions of users and avoid the wrath of a government intent on maintaining atight control over the flow ofinformation.

A new reportfrom theUniversity of Toronto's Munk School of Global Affairs describeshow China's biggest live streaming apps work to shut down discussion on everything from sex and gambling to political gaffes and government corruption.

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"Here you see, over the past year, an industry and a type of application exploding in popularity and it's offering users inChina new and fun ways to express themselves and connect,"MasashiCrete-Nishihata, research manager for the school's internet watchdogCitizen Lab, told CBC News.

"But these expressions and connections are alsothreatening to the government. So companies are caught in this balancing act on the one hand trying to growtheir businesses andleverage newinnovation, whileon the other handmakingsure they don't cross the line."

How it works

Crete-Nishihata and his team downloaded the country's three most popular live streaming apps YY, 9158, and SinaShow and reverse-engineered them toextractsome19,464 keywordsthat trigger censorshipwithin the services' chat features.

Keyword monitoring and filtering just one waythecompanies crack down on unwanted speech works by embedding a list of banned termswithin the application itself.

"If your message contains a keyword from the list then the message is not sent," the report explains.

The list of banned words contains a lot of things you would expect sexually explicit content like "young girl undressing" and "nude video chat," terror-related terms like "improvised explosive devices," and politically sensitive information like "TiananmenSquare massacre."

But a lot of it is reactive.

"Keywords will be added in and around a particular news event,"Crete-Nishihata said.

For example, last month when an translation error caused President Xi Jinping totell G20 leaders that China's economic policy aims to "loosen clothing," the appsadded a total of 17 keywords that referenced the speech.

You can browse the event-triggered keyword bans on Citizen Lab's interactive timeline.

Who calls the shots?

But those events were not censored equally across the three apps. In fact, the lists of banned keywords varied dramatically.

"This suggested that there's no centralized list sent to the companies by government authorities," Crete-Nishihata said.

WhileChina exerts direct control over news media, it appears to take a more hands-off approach with private companies.

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"It's not practical forthe government to control every aspect of censorshipso they need the participation of the private system,"Crete-Nishihata said. It's not a "top-down kind of control. It's much more distributed."

In some cases, the companies even included the names of their competitorsin their ban lists somethingCrete-Nishihata said is motivated "more by businessinterests."

"What we're seeing is that censorship can be driven by multiple agendas," he said.

'Cat-and-mouse game'

Censorship is a full-time job for these companies.

Users, according to Crete-Nishihata, have come up with"playful and creative" use of Chinese language to dodge the censors.

The censors sometimes pick up on these puns, nicknames and alternative spellings and add them to the ban lists.

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"Users and the censors are engaged in this kind of cat-and-mouse game," Crete-Nishihata said.

"Censors will never be able to comprehensively censor speech through keyword filtering systems, but users also will not be comprehensively able to evade these controls. So it's always this kind of balance between the two."

But as moreChinese citizens take up space in the digital sphere, it's becoming a tougher to maintain that balance.

"That's the kind of tension that you see with social media in China."