in april 2017 research highlighted three major threats to monero users' privacy. the first relies on leveraging the ring signature size of zero, and ability to see the output amounts. the second, described as "leveraging output merging", involves tracking transactions where two outputs belong to the same user, such as when a user is sending the funds to himself ("churning"). finally the third threat, "temporal analysis", shows that predicting the right output in a ring signature could potentially be easier than previously thought.