The control of voices within a country is as important to a censor as blocking information from outside. This control must extend to social media. Screening every post prior to publication is not practical; instead, censors find and delete objectionable content after it has been posted. This paper presents GhostPost, a distributed system that conveniently and safely restores deleted posts on any social media platform, with an implementation for Sina Weibo. Our simulations show that even if the censor deletes most posts within two hours (roughly the capability of Sina Weibo’s censor), it cannot prevent a well established GhostPost deployment from preserving a majority of the posts our users would want to see.
