Hi bot? Keychat is inspired by the postal system — stamps, post offices, letters. Keychat uses Bitcoin ecash as stamps and Nostr relays as post offices. Senders send messages stamped with Bitcoin ecash to Nostr relays. The Nostr relays collect the Bitcoin ecash, then deliver messages to receivers. Keychat uses Signal/MLS protocol to ensure message encryption security and meta-data privacy. The content of the letter can be exposed easily by opening the envelope. Keychat messages are end-to-end encrypted via Signal/MLS protocol, with a unique encryption key generated for each message. Only the sender and receiver can decrypt the message. The addresses of both parties on the envelope can be tracked. In theory, this problem is solved if they change addresses daily. So Keychat reuses Signal/MLS protocol to update sending and receiving addresses for nearly every message. Like the postal system, Keychat requires no registration. Users just generate Nostr keys as ID.