WeChat ‘monitors international users’ text messages to preemptively identify content to censor for its Chinese users’
- The Citizens Lab studied how WeChat builds their database of blacklisted terms
- They found the company monitors international messages to preemptively identify potential images or content that should be banned in China
- The app creates a ‘hash’ code for potentially offensive messages, and adds the hash to a database that will block those images from being sent in China
- The system allows the app to censor certain subjects without even being asked
WeChat is monitoring messages sent by international users to help identify content that might need to be preemptively censored in China.
The popular text messaging app keeps a database of censored or potentially inflammatory content that it uses to automatically filter messages for Chinese account holders.
The company keeps this database up-to-date by scanning messages sent between account holders outside of China to preemptively tag new images or other content that might be considered inflammatory by the Chinese government.
The popular chat app WeChat reportedly monitors international chat exchanges to identify and tag content to censor for Chinese account holders
The system was documented in recent tests conducted by The Citizens Lab, a Canadian public policy institute at the University of Toronto.
‘I would urge international users to consider that, as you use this platform, you’re actually helping to strengthen digital repression in China,’ Citizens Lab director Ron Deibert told the South China Morning Post.
Past reporting has shown that WeChat maintains an active blacklist of around 500 keyword combinations that will automatically be blocked in messages with Chinese account holders.
For example, a message that mentions Dr. Li Wenliang, an ophthalmologist at Wuhan Central Hospital credited as the COVID-19 whistleblower, will likely be blocked if the intended recipient is a Chinese account holder.
To try and learn how WeChat builds this blacklist, they tested how the app responded to their attempts to send a new illustration of Liu Xiaobo, an imprisoned writer and activist sometimes described as ‘China’s Nelson Mandela.’
According to The Citizens Lab, the app maintains a database of blacklisted keyword combinations and an index of ‘hash’ codes attached to images or files that should be censored. The hash codes appear to come, in part, from scanning international messages
In one message thread with only account holders from outside China, they sent an image of Liu Xiabo that arrived intact, but was assigned a particular ‘hash’ code by WeChat.
When the researchers sent the same message to a group thread that included a Chinese account holder, they found that WeChat used the ‘hash’ code generated from their earlier thread of international users to identify and remove the image.
They used image editing software to change the content of the image itself in several ways, but ensured it still had the same ‘hash’ code in the image file, but WeChat still automatically blocked the image to Chinese users based on the hash code alone.
The Citizens Lab tested the feature by sending a new illustration of imprisoned Chinese dissident Liu Xiaobo to a goup of international users. They found WeChat generated a new ‘hash’ code for the image and used it to censor the image when later sent to a Chinese user
‘If users [of WeChat] weren’t concerned before, they should be very concerned now and re-evaluate the risks of using this application,’ Deibert said.
In a statement to the South China Morning Post, a WeChat spokesperson said the company takes the report seriously, but, ‘with regard to the suggestion that we engage in content surveillance of international users, we can confirm that all content shared among international users of WeChat is private.’
The company didn’t address any of the report’s specific claims but said, ‘our policies and procedures comply with all laws and regulations in each country in which we operate.’
A spokesperson for WeChat said they take The Citizen Labs’ report seriously but insisted ‘our policies and procedures comply with all laws and regulations in each country in which we operate’
According to Sarah Cook, a research analyst at the think tank Freedom House, the report has ominous implications.
Cook warned that WeChat’s tools could be used for ‘identifying certain users and creating a portfolio about them, [or] feeding other aspects of the [Chinese Communist Party’s] transnational repression apparatus.’
‘This is going to amplify calls for greater scrutiny, especially in the United States, of WeChat,’ Cook said.