Metadata Protection in Instant Messaging Applications: a Review PTS2025

This talk covers the obvious issue of long-term identities and the construction of the social graph and how some protections supposed to thwart the social graph recovery are flawed. Some of these attacks are publicly documented and still unmitigated by those affected by them. This talk also dives into less obvious metadata leaks, such as traffic correlation and ciphertext correlation. Finally it also points out that some of the studied instant messaging solutions do not protect all messages and leak metadata to third parties via attachment upload, push notifications, backups and voice/video calls. Sorting out which instant messaging application is the best is a non-goal for this talk.