Signal is encrypted in transit, only sorta at rest. If someone gets your device you're already in serious trouble. Disappearing messages is the best bet against

Signal is encrypted in transit, only sorta at rest. If someone gets your device you're already in serious trouble. Disappearing messages is the best bet against it, but if someone takes screenshots or the app isn't opened after the time as elapsed and the SQLite database is extracted, you're out of luck.