I’m not an encryption or security expert or anything, but the thing that you have to be careful about with Matrix is that you are going to find yourself most of the time chatting in rooms which log messages forever. That’s not the case with every room; it depends on the settings, participants, and certain events that might cause the room to stop existing in the future or lose its copies of the messages, but generally what you are looking at is the system the way its designed fights against losing that kind of information. (Matrix federation makes the room copied onto as many servers as it can.) You will just want to be mindful of how you chat on there, for example don’t say things you don’t want someone to look up 10 years from now. It’s kind of a privacy nightmare, but you can just try being careful, for example by staying pseudonymous, and if you mess up somewhere delete those messages.
The difference here with XMPP is that, while servers can log chat rooms, most of the time they are configured not to. History is usually temporary just for convenience (that is, offline messaging) and may go back anywhere from a few days to a few weeks. Chat rooms live on only one server that hosts them, so they are not duplicated onto other servers.
In either case, clients could still be logging and so on, so you should always be mindful of how much you trust both the service and the people you are communicating with. E2EE is available on both platforms, which you should utilize anyhow, but mainly I’m talking about public chat rooms.
I’m not an encryption or security expert or anything, but the thing that you have to be careful about with Matrix is that you are going to find yourself most of the time chatting in rooms which log messages forever. That’s not the case with every room; it depends on the settings, participants, and certain events that might cause the room to stop existing in the future or lose its copies of the messages, but generally what you are looking at is the system the way its designed fights against losing that kind of information. (Matrix federation makes the room copied onto as many servers as it can.) You will just want to be mindful of how you chat on there, for example don’t say things you don’t want someone to look up 10 years from now. It’s kind of a privacy nightmare, but you can just try being careful, for example by staying pseudonymous, and if you mess up somewhere delete those messages.
The difference here with XMPP is that, while servers can log chat rooms, most of the time they are configured not to. History is usually temporary just for convenience (that is, offline messaging) and may go back anywhere from a few days to a few weeks. Chat rooms live on only one server that hosts them, so they are not duplicated onto other servers.
In either case, clients could still be logging and so on, so you should always be mindful of how much you trust both the service and the people you are communicating with. E2EE is available on both platforms, which you should utilize anyhow, but mainly I’m talking about public chat rooms.