Expand description
Ordered, reliable broadcast across reconfigurable participants.
§Concepts
The system has two types of network participants: sequencers and validators. Their sets may
overlap and are defined by the current epoch, a monotonically increasing integer. This module
can handle reconfiguration of these sets across different epochs.
Sequencers broadcast data. The smallest unit of data is a chunk. Sequencers broadcast nodes
that contain a chunk and a threshold signature over the previous chunk, forming a linked chain
of nodes from each sequencer.
Validators verify and sign chunks using partial signatures. These can be combined to recover a threshold signature, ensuring a quorum verifies each chunk. The threshold signature allows external parties to confirm that the chunk was reliably broadcast.
Network participants persist any new nodes to a journal. This enables recovery from crashes and ensures that sequencers do not broadcast conflicting chunks and that validators do not sign them. “Conflicting” chunks are chunks from the same sequencer at the same height with different payloads.
§Design
The core of the module is the Engine. It is responsible for:
- Broadcasting nodes (if a sequencer)
- Signing chunks (if a validator)
- Tracking the latest chunk in each sequencer’s chain
- Recovering threshold signatures from partial signatures for each chunk
- Notifying other actors of new chunks and threshold signatures
§Acknowledgements
Autobahn provided the insight that a succinct proof-of-availability could be produced by linking sequencer broadcasts.
Structs§
- Config
- Configuration for the
Engine. - Context
- Used as the
Automaton::Contexttype. - Engine
- Instance of the engine.
- Prover
- Encode and decode proofs of broadcast.