Notifications through FCM: what does Google see?

bayerelm

I'd like to understand how much of a privacy risk it is to get notifications from my apps via FCM (thus with the sandboxed google services installed in my main profile with network permissions).

I understand that ProtonMail, for instance, encrypts the notifications as well so Google cannot see them. Is that standard practice? Does Signal, for instance, do the same? For apps that aren't focused on privacy, should I expect that they do not implement any kind of encryption for notifications and that therefore Google can see them?

Thanks a lot in advance. I'm not on GrapheneOS yet and I'm trying to best understand how I could set it up for my personal case before I buy a Pixel.

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bayerelm Technically Google can see when you get a notification and from what app. I don't think that they are logging this data.

bayerelm

[deleted] okay, thanks. What about the content of the notifications? Say, if I get a message on Signal, does Google see it through the notification?

applesbana

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I think they are not only logging it, but making it accessible to law enforcement (and who knows who else). Seems apple was doing so without even requiring a warrant until recently

https://www.reuters.com/technology/cybersecurity/governments-spying-apple-google-users-through-push-notifications-us-senator-2023-12-06/

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bayerelm I believe technically yes they have access to the title and content, so you should assume they have a permanent record of it.

https://security.googleblog.com/2018/06/end-to-end-encryption-for-push.html

Edit: As noted by @Titan_M2, it is up to the developer to encrypt the content.

Titan_M2

bayerelm What about the content of the notifications? Say, if I get a message on Signal, does Google see it through the notification?

It depends on the app. AFAIK Signal uses FCM only as a wakeup event, to know when to fetch a message from the Signal Server.

bayerelm

Titan_M2 okay, that’s what I imagined. So essentially, it is reasonable to assume that privacy-focused services would probably encrypt the content of the notifications (or at least make it impossible for Google to see it in any other way), but for the rest it might be safer to assume that the content might be readable by Google.

Thanks everyone.

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https://firebase.google.com/docs/cloud-messaging/fcm-architecture

The way I understand it, it doesn't get to see actual message just a request with associated metadata. Sorry, edited, previous link changed

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applesbana this is just one of the facts on which a case against use of (sandboxed) Google Play Services can be built (even on GrapheneOS which has greatly reduced hardware ID and other non-hardware info collection). This doesn't mean people not using them are protected when using proprietary network enabled apps. I trust the OS doesn't spy on me or I wouldn't be here talking to you. I also trust that the potential for IPC with Google Play Services absent is greatly diminished.

applesbana

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Agreed that while it doesn’t mean you’re protected by using apps not relying on play services, imo its less likely for Molly or Fairemail (or other foss apps like this with solid reputations) to sell the notification data or to have law enforcement sweep it up. I imagine the deals in place that Snowden disclosed where apple, google, other big boys just give server access to the govt does not hold with niche apps like Molly.

But I guess no way to verify any of this, just my two cents