SimpleX is an open-source decentralized client-server network that uses disposable nodes to asynchronously pass the messages, providing receiver and sender anonymity.
Messaging apps make it easy to communicate and connect with people around the world. However, with new ways to communicate and connect via technology, there are also new ways for your privacy and security to be breached.
SimpleX is one of the most private and secure chat and applications platform that you can find out there. The main difference of SimpleX Chat is that it does not use any form of identity at all for message routing, requiring to establish initial connection either out of band or via some touch points that do not participate in the message routing, so the only way to build connections of SimpleX network is by observing IP packet times.
On top of that, SimpleX uses two layers of E2E encryption (double-ratchet for duplex connections): One offers forward secrecy, with which the chat still offers protection even if the long-term credentials become known, a second is intended to protect the metadata.
SimpleX Chat uses a SimpleX Messaging Protocol (SMP) protocol to send messages in one direction to a recipient. Unlike P2P networks, all messages are passed through one or several servers, that do not even need to have persistence.
Asynchronous message queues are used here, which can only transmit the data in one direction – also called simplex in communication technology. This combines the advantages and avoids the disadvantages of federated and P2P networks.
So unlike federated networks, the participating server nodes do not have records of the users, do not communicate with each other, do not store messages after they are delivered to the recipients, and there is no way to discover the full list of participating servers.
SimpleX Chat Advantages
No global user identities – no phone numbers, emails, usernames, unique identifiers. In other words, nothing that could allow the network servers to aggregate the communications of users and have visibility of their contacts.
Decentralized client-server network topology and privacy-preserving message routing protocol. SimpleX network has a design similar to P2P networks, but unlike most P2P networks it consists of clients and servers without depending on any centralized component.
No dependence on DNS for the core network. Probably DNS will be used in the future for optional public addresses, but the message routing will not depend on DNS-based user addresses.
How to Use SimpleX Chat
The current 1.0.1 version is stable, robust, and can be used from the command line on all major desktop platforms. In addition, you can deploy your own server, or you can use the SimpleX messaging servers (they are pre-configured in the terminal client).
The terminal chat client supports chat groups and sending files. It is available in SimpleX chat repo – you can either build it from source or download the binary for Linux, Windows, or Mac from the latest release.