The desktop client is in beta right now. I should go public by next week for all platforms save windows. Windows is planned for about a week later. However, in the first phase, there will be no account syncing (but it's on the roadmap). So you will need one account for each device, which is fine imho, since you can set up groups instead of 1-on-1 chats to resolve that issue.
Signal is wannabe private because of phone number, metadata and contacts mining (even though they say they don't, they can). Simplex looks promising and the guy is headed in the right direction. As soon as he makes it that the servers cannot correlate which IP is talking to which IP, I will say they are a really good solution. Telling people to use Tor with your app for privacy is not a solution.
Besides that, it is a very well made app that has a nice UI and works very well. Also many good features.
I did a bit of research for my personal use and what came out as the best options in 2023 are indeed SimpleX and Briar. What do you think of the latter?
Seems that's true. Text-only communication in Briar is built by design. I see this from its communication scheme. I don't think any other message options will come up. So I am also on it in case of the Internet outage. Besides, you can chat properly only when you and your contact are both online. Not a very handy option for daily use.
So SimpleX.Chat for privacy and Matrix for public groups.
Im not a fan of no identifiers. Sure simplex is secure with it but I would like to see something like simplex that uses 24 word seed phrases to generste millions of unique identifiers the user can easily backup and restore from a piece of paper and not from a digital backup file.
That wouldn't work for anonymity because in order to be able to restore from a passphrase or seed, it must be kept somewhere remotely that people can access and activity can be tracked. That's why there's no anonymity with bitcoin.
If all the identifiers are prerendered then they must be stored somewhere discoverable. What you are referencing is the best for security, SimpleX is the best for privacy.
Monero is a privacy coin that allows for multiple subaddresses.
The reason I prefer having identities (subaddresses) and to recover these addresses using a single 24 word seed phrase is for a simple one-time backup of your addresses. This will not backup anything else.
Lets say you generate a subaddress for every single friend you have and then a few years later your phone dies and you did not make a backup in over a year. The seed phrase will be able to recover your subaddresses. You may not know who address is for which friend, but as long your friend knows they can contact you and you will still receive the message.
If simplex implements multiple reuseable addresses that are generated by a seed phrase like a cryptocurrency, it will be a killer app. I am not against removing the single use one time codes to establish communications, that is a cool feature, just not possible to backup these communications on paper.
Paper backups are considered the most secure since it is not backup using a computer.
Anyone can set up a server indeed, and you have no real way of knowing if you can trust them or not.
The official SimpleX chat website has this nice advice in this regard:
The servers have separate Anonymous credentials for each queue, and do not know which users they belong to.
Users can further improve metadata privacy by using Tor to access servers, preventing corellation by IP address.
But IMHO if you need Tor to get the resemblence of metadata privacy, why use SimpleX at all and just use XMPP with Tor with works great?
To me this SimpleX is pure techno-solutionism that tries to solve a hypothetical problem and ends up as basically security LARPing and not solving many real-world threat-models at all.