What our meeting point knows about you
Let's start with the basics. Our meeting point knows exactly three things about you: your username, your unique identifier, and a hash of your password. A hash is an irreversible mathematical transformation — it can verify your password is correct without knowing what it is. Your real password only exists in your head and on your device.
Nothing else. We don't store who you speak with or what you say. Your tunnels and the names of your contacts only exist on your device, encrypted, and our meeting point cannot open them even if it wanted to.
The mailboxes
Imagine a wall of numbered mailboxes, like in an old post office. When your app wants to connect with someone, it leaves a note in a mailbox saying 'I want to talk to user X'. Nothing more. It doesn't say who you are. It doesn't say what you want to talk about. Just a note in a mailbox.
Every now and then, all apps connected to Solo2 check the mailboxes in case someone has left a note for them. It's like stopping by the post office and asking: "Is there anything for me?". If your contact finds your note, they ask the meeting point for the IP address you left. It gives it to them. The address is kept in the server's memory for a few seconds and is never written to disk.
From that point on, the meeting point disappears
Once both devices know each other's address, they talk directly to each other. The meeting point no longer participates. If a direct connection is not possible, messages pass encrypted through our mirror, which stores nothing. It doesn't store them. It doesn't know whether the connection was established or not. It doesn't know how long it lasts. It doesn't know how many messages are exchanged or how large they are.
So much so, that if the meeting point shut down at that moment, in a direct connection the two users would continue talking exactly the same. The conversation doesn't depend on it. It only depended on it for the two devices to find each other. Once connected, it is irrelevant.
The conversation is secure before it even starts
When two people create a tunnel in Solo2, their devices exchange public cryptographic keys. From that moment, each message is encrypted with the recipient's key — and only the recipient can decrypt it. This happens before any conversation begins. The keys are ready from the moment the tunnel is created.
That's why, when the two devices connect directly, the communication is already protected. They don't need to negotiate anything. They don't need to ask the meeting point for permission. The keys are theirs, on their devices, and nobody else has them.
What this means in practice
That your conversations are not stored on any server. There is no message database to hack. They travel encrypted from your device to the other person's.
The next time someone tells you an app "encrypts your messages end-to-end", ask them about everything else: who knows your contacts, what time you speak, how often. If the answer is "our server, but we don't use it for anything bad", that's a promise. In Solo2 the answer is different: your contacts are encrypted on your device and we don't store who you speak with or what you say.