You could try Jami. It's peer to peer, so essentially any participants are self-hosting it. Its E2E encrypted, supports group messaging, voice and video calling, has easily 'linkable' mobile and desktop apps for all platforms and requires no email address or phone number to use. It's also the only messenger I'm aware of which is endorsed by the Free Software Foundation. I highly recommend it 👌
I recommend Matrix with the Conduit server. This server requires almost no resources and even runs on a Raspberry Pi.
Cinny works perfectly as a desktop client (in case you want to escape from the ubiquitous Element). And for mobile I would use Element for Android/iOS although FluffyChat also works very well.
Yes, without a doubt, for me it is the most balanced client, a pity that there is not for Android, but well, in mobile Element does not give problems either.
They are very focused on development and therefore the documentation is a bit sparse (maybe).
The truth is that it is not very complicated to install. It is simply to download the binary (it is statically compiled so it has no dependencies) place it in /usr/bin and execute it (the best is to create a user in the machine with the home in /var/lib/conduit and then launch it with systemd).
XMPP only does it with certain client extensions. And Matrix only does it when the rooms are set up this way. SimpleX does what you want, but is kind of unintuitive for the average user.
I say go with Signal, it does what you want and is idiot-proof.
Signal is annoying to use if you don't have a smartphone you can trust, since they do not allow registration from desktop. So either an Android VM or Signal-cli. But maybe it was just a one-off bug that the desktop client didn't bind to signal-cli for me. Still, the fact that you need an unofficial command-line application just to register makes it not exactly user-friendly.
I imagine that most people's families will find Singal easier than using a CLI program anyway. It's rare to find an entire family without typical cellphones.
Yea, but a typical cellphone is not as easy to make private as a typical laptop or desktop. Lineage has some tradeoffs and not accessible on all devices, and Graphene needs even more specific, quite expensive hardware!
Good luck getting grandma to install and use Graphene or Lineage on their 3 year old underpowered Samsung device that already works the way they know.
I think you're making problems where there aren't any. A device PIN or fingerprint along with Signal is probably way more secure than any family chat needs to be.
I meant telemetry to Google and/or manufacturer. With grandma, I can at least install Linux on her laptop and say to message me there (that's pretty much what I did with mom).
E2E is complicated, if you self-host for a group, having TLS and encrypting data at rest (storage) may be enough. Get a threat model. That being said, I would recommend snikket.org which is a superset of extensions over XMPP which is the open source IM that was the base of almost every app out there. Matrix and Rocket are both alright too. Depends too on your resources, synapse requires too much RAM (or so I heard)
Yes, XMPP with proper TLS on the server side and Conversations or one of its forks (preferably fetched from F-Droid) using OMEMO encryption should be good enough.
If you are brave or paranoid, give Tox a try: https://tox.chat/
There are literally multiple big screenshots on the page I linked and a big join button that brings you to https://join.movim.eu where you can chose an instance.
There must be something wrong with your browser. There are multiple big screenshots in a slider on https://movim.eu
And the unrestricted instances on the join page can be used with any xmpp account, however I don't recommend it as servers running Prosody currently only support a subset of Movim's features.
Matrix is slow on large instances, but that's not the case here, especially if no federation is done.
And the issue with sluggishness is currently the main development focus with ElementX/matrixX that will become mainstream matrix soon. With that even the large instances are extremely fast.
Matrix is slow everywhere. Anyone who says otherwise is lying. Element X is also super slow. Waiting 5-10 secs for messages to appear every time I open the app. I know what I'm talking about.
Because there are very very few Sliding Synch (which is the part of X that makes it faster) instances at the moment and only one that has a major userbase.....
I know it's not self hosted but why not Signal? Matrix is demanding on a SBC and your family would probably get the 'unable to decrypt message, please re-verify keys' error that happens in encrypted matrix group chats and Element does not have the best UI especially if you want your grandma to use it.
What's your source on the reverify thing? I use matrix a lot, and this hasn't been an issue I ever experienced anymore since they introduced cross-signing a couple years ago.
Same goes for the common clients such as element. It has been clunky in the past, but after the past major overhauls ( also years ago now) everything has been silky smooth for me, if not better than others. The one thing left I prefer from Signal is the one-time photo share.
Matrix is great, clients are great too, only the server part still is annoyingly complicated and messy. Would only recommend that for tinkerers, on that case it's a great path to learning about the complexity of addressing lots of security concerns that others gloss over.
Edit: to add - there's a reason why the French government and the German military decided to build their secure internal IM infrastructure on Matrix. Obviously they are hosting their own private network, but if the concept is good enough for European government and military, it is an indicator for quality especially in terms of security and privacy.
However, I wouldn't host on a Raspberry Pi or even at home for that matter. Get a VPS and host it there. Linode even has a one click app install for Simplex Chat