Understanding the cryptographic machinery behind MicroChat, from simple analogies to deep protocol mechanics.
Imagine you want to send a letter to your friend, but you have to pass it through a stranger's house (our servers).
With standard messaging, you trust the stranger not to open the envelope. With MicroChat, you put the letter in a steel box that only you and your friend have keys to. The stranger passes the box along, but can never open it.
What if someone steals your key tomorrow? Can they read your messages from last year?
No. MicroChat changes the locks on the box whenever the group rotates its keys — when someone joins, leaves, or manually rotates. Once a lock is replaced, its old key is shredded. Even if a thief steals your keys today, they can never unlock the boxes from before the last rotation. This is called "Forward Secrecy".
Normally, the stranger carrying your box (our server) knows exactly who sent it and who it's going to.
In MicroChat, we use a system called Sealed Sender. You take an anonymous delivery token and drop off the box. The server verifies the token but has no idea who you actually are. You are a ghost.