Limiting the Spread of Fake News on Social Networks by Users as Witnesses.

In this paper, we study how users can act as witnesses to limit the spread of fake news. We present a new technique based on consulting a set of users, called witnesses. Before resharing a content $M$ by a user $A$ , a set of $k$ users (witnesses) are selected randomly, by the system, from the friends set of $A$ . Witnesses are asked to validate the content $M$ after allowing the user $A$ to re-share it. If there is an authenticated user $AU$ , among this set of witnesses that validating $M$ , the user $A$ is allowed to re-share it without considering the others $(k-1)$ responses. In the case where all witnesses are non-authenticated, if at least one witness rejects the content $M$ , the user $A$ is not allowed to re-share it. Note that $A$ has no knowledge about the set of selected witnesses.