# Coordinator

The coordinator is a service which communicates with all of the processors,
all of the other coordinators over a secondary P2P network, and with the Serai
node.

This document primarily details its flow with regards to the Serai node and
processor.

### New Set Event

On `validator_sets::pallet::Event::NewSet`, the coordinator spawns a tributary
for the new set. It additionally sends the processor
`key_gen::CoordinatorMessage::GenerateKey`.

### Key Generation Event

On `validator_sets::pallet::Event::KeyGen`, the coordinator sends
`substrate::CoordinatorMessage::ConfirmKeyPair` to the processor.

### Batch

On `substrate::ProcessorMessage::Batch`, the coordinator notes what the on-chain
`Batch` should be, for verification once published.

### SignedBatch

On `substrate::ProcessorMessage::SignedBatch`, the coordinator publishes an
unsigned transaction containing the signed batch to the Serai blockchain.

### Sign Completed

On `sign::ProcessorMessage::Completed`, the coordinator makes a tributary
transaction containing the transaction hash the signing process was supposedly
completed with.

Due to rushing adversaries, the actual transaction completing the plan may be
distinct on-chain. These messages solely exist to coordinate the signing
process, not to determine chain state.
