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Signal messages retrieved from iOS notification, as seen in Prairieland federal trial
(media.fedia.io)
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).
good question, and I was wrong.
as of this latest commit, push notifications are represented by PushNotification types. the notification message is the 4th parameter in the constructor.
this kind of object is created in PushNotificationManager and PushNotificationScheduler.
out of 6 functions that send a notification, 1 actually sends notifications of messages, and it omits putting in the message part: https://github.com/signalapp/Signal-Server/blob/75948dc6174ed091180aa20c018fa0f353130ee0/service/src/main/java/org/whispersystems/textsecuregcm/push/PushNotificationManager.java#L49
so the signal server does not send
{"urgent": true}to firebase, it sends no message, just kind of a ping in my understanding.