nomos-node/mixnet

Mixnet

Components

• node: A mixnode implementation that will be assigned to one of the mixnet layers and will be responsible for receiving packets and forwarding them to the next mixnet layer.
• client: A mixclient implementation
  • which splits a message into multiple Sphinx packets, constructs mix routes for them, and sends the packets to the first mixnode in each route.
  • which receives Sphinx packets from a mixnode and reconstructs a message.

Recommended Architecture

flowchart LR
    subgraph layer-1
        mixnode-1-1
        mixnode-1-2
    end
    subgraph layer-2
        mixnode-2-1
        mixnode-2-2
    end
    subgraph layer-3
        mixnode-3-1
        mixnode-3-2
    end
    mixnode-1-1 --> mixnode-2-1
    mixnode-1-1 --> mixnode-2-2
    mixnode-1-2 --> mixnode-2-1
    mixnode-1-2 --> mixnode-2-2
    mixnode-2-1 --> mixnode-3-1
    mixnode-2-1 --> mixnode-3-2
    mixnode-2-2 --> mixnode-3-1
    mixnode-2-2 --> mixnode-3-2
    mixclient-sender-1 --> mixnode-1-1
    mixclient-sender-1 --> mixnode-1-2
    mixnode-3-1 --> mixclient-senderreceiver-1
    mixnode-3-2 --> mixclient-senderreceiver-2

The mix node component can be integrated into a separate application, for example, so that it can be run independently with mixclients for better reliability or privacy.

The mix client component is also designed to be integrated into any application that wants to send/receive packets to/from the mixnet. The client can be configured with one of modes described below.

Mixclient Modes

• Sender: A mixclient only sends Sphinx packets to mixnodes, but doesn't receive any packets from mixnodes.
• SenderReceiver: A mixclient not only sends Sphinx packets to mixnodes, but also receive packets from mixnodes.
  • Due to the design of mixnet, mixclients always receive packets from mixnodes in the last mixnet layer.
  • Currently, only 1:1 mapping is supported. In other words, multiple mixclients cannot listen from the same mixnode. It also means that it is recommended that a single node operator runs both a mixnode and a mixclient.