Chinese social media giant WeChat is screening documents and images shared by overseas users, according to researchers from the Citizen Lab of the University of Toronto.
As of late 2019, the messaging app is said to have had more than 1 billion active users on a monthly basis, sending around 45 billion messages daily.
According to the study, the company has been silently surveilling and analyzing millions of files shared by international WeChat users via a remote server hosted by Chinese Internet provider Tencent.
“Like any other Internet platform operating in China, WeChat is expected to follow rules and regulations from Chinese authorities around prohibited content,” the researchers said. Later adding that, “companies are expected to invest in human resources and technologies to moderate content and comply with government regulations on content controls. Companies which do not undertake such moderation and compliance activities can be fined or have their business licenses revoked”.
In the most recent report, entitled ‘We Chat, They Watch,’ Citizen Lab observed that the app’s remote server scans for “politically sensitive” content, adding a digital signature (MD5 hash) that assures no Chinese users can see the shared files.
Researchers conducted several experiments by running two separate channels. The first channel was set up to communicate entirely with non-China-registered accounts, while the second used a China-registered WeChat account. While no censorship of communication between non-China-registered accounts was detected, the study showed that “such accounts are nevertheless subject to content surveillance.”
“Such surveillance was discovered by confirming that politically sensitive content which was sent exclusively between non-China-registered accounts was identified as politically sensitive and subsequently censored when transmitted between China-registered accounts, without having previously been sent to, or between, China-registered accounts,” they added.
The analysis also shows that files containing prohibited topics and shared between non-China groups are only surveilled. If the same file is sent to a China group chat, however, the document is censored in real time.
“In the case of image files, we observed that sometimes WeChat censors them in real time even if they have not previously undergone content surveillance on the platform,” Citizen Lab said.
While the data gathered cannot demonstrate how long non-China users’ files have been surveilled, the team concluded that “files deemed politically sensitive were used to invisibly train and build up WeChat’s Chinese political censorship system.”
Researchers still have many questions, and although additional information was requested from both WeChat and parent company Tencent, the two companies have failed to respond to inquiries regarding WeChat’s privacy policies.