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Comment by wruza | Hacker News Reader

You don’t have to put an entire message text into APNS notification. Apple (and google GCM, and webpush) notifications only deliver a structured event to the application (which may or may not contain any text), and once the app is activated (if not yet), it has to connect to its own server to get a full representation of what was sent, update vv-status, etc. APNS/GCM are not instant messengers on their own, though may be used as such in simple cases.

the main reason I'm switching to Android

You may be interested in reading this comment then: https://www.reddit.com/r/signal/comments/ap9lin/comment/eg7v...

Likely, iOS version of Signal uses the same “empty ping” technique, so you don’t have to worry about Apple reading your texts, unless you’re concerned with metadata leak. But unless they’re spoofing a websocket with fake packets, it will leak anyway.

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Sure, but there still needs to be a server somewhere that has the app developer's client certificate, connected to Apple, that knows when you get a DM and can send that zero-content "wake up and check your DMs" packet to your phone via APNS, which means it needs (given current apps permissions models) access to your DMs without you.

There is no need for this “server somewhere”, and APNS can’t have your message, mainly for two reasons:

First, that “server” is Signal server itself. When a message arrives at it, it simply commands Apple to wake up your app, for it to call home, and that’s it. It is preconfigured to do that (and GCM as well).

Second, all Signal messages are end to end encrypted and neither of Apple, Signal, Google, your ISP, any server on the route of it NEVER know its content, because the only mean of decrypting it resides in a memory of your client app. There is basically no way to see the contents before your client receives the message, by design. Even if that were not the case, various IM servers don’t have to send your texts to Apple, only if they want the text to be shown on a notification itself.

The only theoretical concern here may be that Apple can somehow pick the decryption key out of the app’s memory (because ios is a supervisor, obviously). But that can’t be the main reason someone swithces to android, which is a supervisor itself, and where the same issue exists.

We're talking about federated/decentralized protocols that Pidgin serves as the type of client for, in a thread about why we don't see things like Pidgin on iOS.

In a centralized system where the mobile app is made by the same people as the IM server, of course the IM server can send a notification to the app (such as is done in e2e stuff like Signal, or in non-e2e such as Telegram).

That falls apart when you're talking about, say, ActivityPub on an instance you run yourself, or one not operated by the vendor of the IM app. The developer's server can't know when to send you a notification without having some knowledge, from your own e.g. IRC, ActivityPub, or Matrix server, that you have received a new DM.

The Matrix/Element people have addressed this by running one centralized notification service for every single client of the Matrix/Element iOS app.

We're talking about federated/decentralized protocols that Pidgin serves as the type of client for, in a thread about why we don't see things like Pidgin on iOS.

Sorry, I misunderstood that.

It doesn't need access to the content of the messages.

Sure, but it needs to know that there are new messages. I don't think that's a separate permission on any (e.g.) ActivityPub/XMPP/IRC server implementation today.

On all XMPP server implementations I've worked with, the push notifications mechanism supports (and usually defaults to) not including any message body in the API call to the push server. Usually it's also possible to leave out the sender name/JID, e.g. with prosody's mod_cloud_notify.

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