SimpleX Chat - Decentralized chat with a focus on users’ privacy

The world's most private and secure chat - open-source, decentralized, and without global identities of any kind. You can use it from the terminal UI, with all contacts and groups in one window. It is a federated chat system with end to end encryption support and low risk of man in the middle attack.

It solves privacy problem by making both messages and contacts accessible only on client devices, reducing the role of the servers to simple message brokers that only require authorization of messages sent to the queues, but do NOT require user authentication.

Simplex messaging protocol (SMP) for messaging via secure persistent queues will serve as the low level protocol for SimpleX chat. It uses different encryption keys for each message queue - the key is passed via existing secure channel - e.g. QR code or another simplex queue.