Why? I think Google suggests that you send the payload encrypted through the notification. Google then only knows which app to send the message to, they don't know from whom the message originates (only "a Telegram server") nor what the content is.

Also, you could just send a notification instructing the app to fetch a new message from your server.

From the docs:

Encryption for data messages

The Android Transport Layer (see FCM architecture) uses point-to-point encryption. Depending on your needs, you may decide to add end-to-end encryption to data messages. FCM does not provide an end-to-end solution. However, there are external solutions available such as Capillary or DTLS.

https://firebase.google.com/docs/cloud-messaging/concept-opt...

Assuming an adversarial relationship, what sort of metadata could Google capture simply knowing which app was sending the notifications and who was receiving them?

Aren’t notifications enqueued on the server side, implying sender info is inscrutable? I’m curious what mechanism you’d propose to gather any valuable metadata given a sufficient volume of encrypted notifications.

Schneier mentioned this late in 2023:

https://www.schneier.com/blog/archives/2023/12/spying-throug...

> Wyden’s letter cited a “tip” as the source of the information about the surveillance. His staff did not elaborate on the tip, but a source familiar with the matter confirmed that both foreign and U.S. government agencies have been asking Apple and Google for metadata related to push notifications to, for example, help tie anonymous users of messaging apps to specific Apple or Google accounts.

"A Telegram server used FCM to send a message of size X to the device owned by individual Y at this timestamp and this IP address".

Nothing else.

If the text appears on your screen I'm pretty sure there are ways for Google to capture it. I don't need to know how android's API works, knowing it probably just makes one blind to the big picture. You have to trust your OS/phone maker not to do a MITM.

Yes, but Google cannot be compelled to turn over data they don't actually have on their servers because the users encrypted it before it arrived with keys Google don't control.

Signal could modify the application so a remote flag in the Play store binaries could be triggered to exfiltrate data as well. But the key distinction is the normal path of Signal gives them absolutely nothing they can tell anyone other then the bits they've put in the disclosure reports (namely: date and time an account ID used Signal I believe).

I think parent's point is, if data appears on sceen, the OS in theory can capture it and send to Google servers as screenshots or OCR'd text.

Yes, that likely is the GP's point, but it's not really relevant to the discussion going on in this thread. Certainly Google could "backdoor" its OS in that way, but they have little motivation to do so (and a lot to lose if they were to do so and were found out). Their recent move to make their location history / timeline product an on-device-only feature because they don't want to have to respond to law enforcement requests for user location data would seem to suggest they really would prefer to not have this sort of data.

At any rate, the discussion going on here is about how Durov has been arrested because Telegram refuses to respond to law enforcement requests, when they do have the ability to do so; and if they were to actually implement E2EE by default (and for group chats), Durov would likely not be in trouble, since Telegram would be unable to provide anything when requested.

> Their recent move to make their location history / timeline product an on-device-only feature because they don't want to have to respond to law enforcement requests for user location data would seem to suggest they really would prefer to not have this sort of data.

I suspect that isn’t the motivation. GDPR says that you have to give users choices about data stored like this (including right to be forgotten, how it’s processed and used and so on), and this becomes a technical, legal and commercial nightmare very quickly. The easier route is just to get rid of it if you can.

This saves Google money (it likely wasn’t that useful to sell to advertisers), makes legal compliance a lot easier and de-risks them from very large fines.

I suspect that the EU lawmakers didn’t think about second order effects like making it harder for law enforcement to access this data in scenarios like this.

Google (and Apple) has remote root over their message bus. This is reflected in the fact that they can remove spyware from people's phones remotely at any time.

Should they have to comply with law enforcement they have much more straightforward ways of doing so than capturing messages off screen.

The app can decrypt the notification before it's displayed.

I don't think the plaintext is required to be part of the API call

And yet Telegram doesn't allow to have e2ee chats on a Linux desktop or phone. You must rely on Google/Apple.

Most of Telegram clients except initial mobile apps was actually open source projects that was choosen by company to become "offcial" ones.

They just dont implement E2EE since almost no one uses it on Telegram.

This claim is what really makes me skeptical of Telegram's privacy story. Their assertion is completely incorrect. (Source: have implemented end to end encrypted payload delivery over APNs / GCM.)

And if they are so off base on this, they must either be incompetent or liars. Neither of which builds trust.

I’m old enough to remember when Signal first implemented cross-device sync using a Chrome plugin.

I’d rather developers issue cautionary warnings than give a false sense of perfect security