alt Hacker NewsThey have to. The device storage is itself encrypted, so the FBI already broke into the phone. When the device is unlocked, notifications are visible by design and therefore available in plain text to the user. The edge case is with disappearing messages, a feature Apple did not build for. The message is intended to be plainly visible to the user, but only for a controlled time on the assumption that the users privileges may eventually be compromised.
This makes for a very odd and specific interaction with a 3rd party feature. Security is a hard problem.
Signal (at least on iOS) has a setting called "Notification Content" which defaults (unsafely in the light of this bug) to "Name, content, and Actions", but allows you to select either "Name Only" or "No Name or Content".
I assume that "Name only" option results in the push notification only sending "Signal message from Bob", and the "No Name or Content" one only sending "You have a new Signal message" - instead of the whole "Signal message from Bob: Let's rob the bank tomorrow!"
If I could have it work the way I'd prefer, Signal would let me set those Notification Content on a per contact and per chat basis - so I could set my bank robbing crew and group chats to "No Name or Content" while leaving mom and the family group chat on "Name, content, and Actions".
(But realistically, if I _did_ have a bank robbing crew they'd all be on my burner phone, not the phone I do family group chat with.)