Does anyone know how iMessage handles this on desktop (on Macs) as they (as far as I know) upgraded their encryption recently?

I don’t but many people do since many creators use Twitter for that. I personally don’t get why they don’t switch to Mastodon or another Fediverse software since there are probably NSFW instances too and if not some of them could team up and create one.

Well Twitter is still used by Musk fanboys, right wingers, from people who don’t understand Mastodon and/or the Fediverse and probably from people who use it for porn.

The good thing here is that you don’t need to trust the server in order to have a secure communication since your clients decrypt and encrypt and not the server.

Yes they can optimize with things like this but that doesn’t make it insecure. It’s still the most secure solution that the average person can use.

Threema doesn’t even have the server open sourced at all, are for profit and their encryption has been compromised.

Session is shady.

Matrix is a metadata nightmare due to it’s federated aspects.

SimpleX is the only thing that is secure, anonymous and good in this regards but it has some small details left that prevents people from switching. I.e. simple things like the fact that you can’t see an overview of your images and videos sent in a chat without scrolling up all those messages. It seems trivial but for the average user stuff like that is important since they know it and use it every day in other messengers.

Signals server is open source. You can run a server. You just can’t connect to the main net because each server is it’s own thing so it doesn’t make sense besides for development purposes.

Please don’t spread misinformation.

• Signal server is open source (as said) and thus can be verified: https://github.com/signalapp/Signal-Server
• and no they can’t see who you message as you can read in the technical specifications of the protocol: https://signal.org/docs/

SSL on websites also is encryption. Still you can post your precious pictures “encrypted” via SSL for the whole world to see. I think everyone knew what was meant with encryption in this context.

SimpleX is great. BUT it’s not user friendly. Thus general adoption for the average user will be hard. Don’t get me wrong using the app itself is easy but as soon as someone switches their phone that doesn’t have technical knowledge they will loose their chats because they won’t understand the concept of moving their DB. Since you don’t have an identifier like a phone number with SimpleX those people could even lose contacts as a whole since they generate a new DB, hurting their social connections.

That’s the reason I personally never recommend SimpleX to anyone who doesn’t have the technical knowledge to understand stuff like that.

The server / backend is not open source. Even though it’s audited that’s a red flag.

Signal can’t see who is texting who. They can’t see which groups you are part of. Those information are end to end encrypted, same as your chats itself, your profile picture, your stories, etc.

Signal doesn’t store message timestamps either.

What Signal itself knows of you is your phone number, the timestamp of your registration, the timestamp of your last connection to the server. That’s it.

Yes metadata is critical but Signal handles metadata very well. Indeed, even though I’m a fan of Matrix, better than Matrix. Matrix is a metadata nightmare due to it’s centralized structure and the way the protocol works.