TLDR: signal content in Apple notification can be retrieved even after signal app deletion.
I saw from this reddit thread: Signal messages retrieved from iPhone after uninstalling app. : signal
Referencing this news article: Pretti Killing May Affect ICE Prairieland “Antifa Cell” Terrorism Trial
The mention of signal is in court documents here: March 10: Federal Trial Day 12 - Support the Prairieland Defendants
Signal chat evidence from Sharp’s device (Exhibit 158):
Messages were recovered from Sharp’s phone through Apple’s internal notification storage — Signal had been removed, but incoming notifications were preserved in internal memory. Only incoming messages were captured (no outgoing).
I learned about this a couple of months ago and I’ve since disabled previews in notifications. It’s unfortunately the nature of how notifications are delivered to you. You should be fine by disabling message previews in your notification settings.
Yup,
https://www.privacyguides.org/articles/2022/07/07/signal-configuration-and-hardening/
Among other things
I think on android, signal do not use Google’s push notification. They simple send a dummy push, and the signal app wakes up to retrive the latest message directly from signal server.
So Google never have your notification content. I am not sure if they do the same on iOS.
That being said if your attack model includes people reading your notification lock screen, then you should disable showing signal notification.
Source?
https://mastodon.world/@Mer__edith/111563865413484025
The message preview notification is handled similarly in IOS and Android. The issue isn’t people seeing the notification, it’s that the content of the message being passed to the phone’s launcher. Which is unencrypted.
Does that actually prevent the app from sending the content through Apple’s servers or does it just prevent iOS from showing it in the notification area?
The only way apple is seeing it is when the notification is displayed. It only sees the contents of the notification itself. So it would still see who sent you a message, but it wouldn’t say what it was
It’s worth noting apps can avoid this on Android: https://tuta.com/blog/google-push-alternative#alternatives-to-google-push
Any FDroid app cannot use Firebase for push notifications since it’s proprietary: https://forum.f-droid.org/t/firebase-allowed-in-fdroid-apps/7540
It’s not because of push notifications. the message is not sent to firebase, just a signal that the app should do a refresh.
It’s because the system saves the notifications apps posted to the notification menu.
but yes. don’t use firebase push notifications if you can avoid it. use a unifiedpush based system. base signal app does not support it, only molly. there are some difficulties though with that that are unique to signal.