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.

This document provides a high-level introduction to deep packet inspection, Internet filtering, and targeted intrusion dual-use technologies with the aim of familizaring the reader with their key technical features, the surrounding international human rights law framework, and some of the leading research to date on their deployment.

本报告延续上一篇针对微信朋友圈图片过滤技术的研究，分析微信如何在聊天功能中实现实时图片过滤。微信是中国腾讯控股有限公司旗下的即时通讯应用，目前是中国最受欢迎的聊天软件之一，也是全球排名第四的最流行聊天软件。朋友圈是微信上最常用的功能之一，其中图片是用户最期望看到的内容分享形式。