[mfwoods]

> not proxying through your phone which Signal used to do and maybe still does

This is what Whatsapp does. Signal never did and has real multi-device support.

> and the Signal server is closed source

It's not: https://github.com/signalapp/Signal-Server

[fro0116]

> This is what Whatsapp does. Signal never did and has real multi-device support.

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.

[xashor]

You must link a client with a mobile device, but after that apparently you can use e.g. the Desktop client without your mobile phone turned on.

[amiraliakbari]

Although Signal is not closed-source, they tend to discontinue useful features of their product. For example RedPhone server code has been removed from GitHub after it was discontinued.

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.

[mfwoods]

I assume they removed it because they don't want anyone to use old insecure code. The RedPhone server hasn't been used for years now and was replaced with a better implementation.

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?

[blfr]

I wish Signal did route through the phone and allowed to send regular texts from other devices.

[lucb1e]

But that's more of a feature request, or even a completely different product ("I would like to send SMS from my desktop"), than a design decision for a chat application's protocol.

[blfr]

Sure it's a feature request but a feature that would be much simpler if the messages were routed through the phone any way.

[lucb1e]

Your message history is always synchronised between devices, it doesn't sound like rocket science to make the client detect when a message is meant to be sent as SMS. No need to make the design choice of routing all traffic through the phone for that.

[lucb1e]

Corrected, thanks!

Curious though, why does WhatsApp not do it if they use the same protocol anyway? Why bother with the phone as an annoying proxy?

[mfwoods]

Only the encryption layer of the protocol is the same, they are not really compatible otherwise.

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.