This report performs the first public analysis of MMTLS, the main network protocol used by WeChat, an app with over one billion users. The report finds that MMTLS is a modified version of TLS, however some of the modifications have introduced cryptographic weaknesses.
We conducted the first analysis of WeChat’s tracking ecosystem. Using reverse engineering methods to intercept WeChat’s network requests, we identified exactly what types of data the WeChat app is sending to its servers, and when. This report is part one of a two-part series on a privacy and security analysis of the WeChat ecosystem.
This FAQ accompanies the full report on privacy in the WeChat ecosystem. We analyzed privacy issues with popular app WeChat by reviewing the data collected by the app and sent to WeChat servers during the regular operation of its various features. We find that they collect more usage data than is disclosed in the WeChat privacy policy.
As a follow-up to our March 2020 report, we conducted daily tests on WeChat and collected 2,174 censored keywords between January to May 2020. This data provides a view into how narratives and messaging on the pandemic are controlled and molded on social media in China.
On May 7 2020, the Citizen Lab published a report that documents how WeChat (the most popular social app in China) conducts surveillance of images and files shared on the platform and uses the monitored content to train censorship algorithms. This document provides a summary of the research findings and questions and answers from the research team.
WeChat communications conducted entirely among non-China-registered accounts are subject to pervasive content surveillance that was previously thought to be exclusively reserved for China-registered accounts.
The analysis of YY and WeChat indicates broad censorship—blocking sensitive terms as well as general information and neutral references—potentially limiting the public’s ability to access information that may be essential to their health and safety.
In this work, we study how Tencent implements image filtering on WeChat. We found that Tencent implements realtime, automatic censorship of chat images on WeChat based on what text is in an image and based on an image’s visual similarity to those on a blacklist. Tencent facilitates this realtime filtering by maintaining a hash index of MD5 hashes of sensitive image files.
This report demonstrates the technical underpinnings of how WeChat image censorship operates and suggests possible evasion strategies.
The 19th National Communist Party Congress was held from October 18-24, 2017. WeChat, China’s most popular chat app, blocked a broad range of content related to the Congress.
