FBI case shows push notifications can expose message content

In short: A report described a case where the FBI obtained message text from an iPhone’s saved push notifications, including for encrypted chat app Signal.

What happened

A report highlighted a recent FBI case where investigators got copies of Signal messages that were sent to a defendant’s iPhone. Signal is known for encryption, which is a way of scrambling messages so outsiders cannot read them.

In this case, the message contents appeared in push notifications, the pop-up alerts you see on your phone’s lock screen. Those notifications were still stored in the iPhone’s internal memory, even after Signal had been removed from the phone before the FBI seized it.

The underlying issue is not limited to Signal. Any app that shows message previews in push notifications can potentially leave behind readable snippets in notification records, depending on how the phone saves them.

Why it matters

Many people treat encrypted messaging as a sealed envelope. Push notifications can act more like a postcard (a short preview that can be read without opening the app). If your phone stores those previews, they may be accessible later if your device is searched.

WIRED notes that Signal users can reduce what shows up in future notifications by changing notification settings to display “Name Only” or “No Name or Content.” That does not change how encryption works inside the app, but it can limit what appears in the pop-up alert.

Source: Wired