This is what Whatsapp does. Signal never did and has real multi-device support.
> and the Signal server is closed source
This is what Whatsapp does. Signal never did and has real multi-device support.
> and the Signal server is closed source
This is news to me. Curious then, why is it not possible to use Signal desktop without a phone?
https://support.signal.org/hc/en-us/articles/360008216551-In...
> Can I install Signal Desktop without a mobile device?
> Signal Desktop must link with either Signal Android or Signal iOS to be available for messaging.
Last time I checked, it is not really feasible to setup a standalone Signal instance. Is there any guide to deploying a standalone version of Signal on your own servers or a successful example of it? If not, their approach may be more of "see but not touch" than being a free software. Also decisions like dependency on GCM and discontinuing features to increase development speed make Signal less reliable as a open source project.
You're right there's no official support on their server, but there are some unofficial guides on their community forums on how to set it up. Also, GCM is not a hard dependency. On Android it will fall back to using only websockets (and no GCM) when Google Play Services is not installed since some time. What other features have they removed without replacement?
Curious though, why does WhatsApp not do it if they use the same protocol anyway? Why bother with the phone as an annoying proxy?
I assume it's a design trade-off when you have E2EE and don't store any messages on the server. With Signal (and I assume Wire) you have to register each device and each device needs to manage its keys. Every message is send multiple times, once for each device, and each device has an independent message queue on the server. That's why you only get the messages from after you registered the device.
Whatsapp doesn't have to do any of that and can just keep the keys on one device.