Shared Publisher
Overview
The Shared Publisher is Ethera's coordination layer for atomic cross-rollup execution.
It allows multiple rollups to participate in one coordinated action without giving up control over their own sequencing, fee markets, or execution environments. Instead of replacing local sequencers, the Shared Publisher coordinates the cross-rollup part of the flow and ensures that the participating rollups reach one commit-or-abort decision.
Key Properties
- Sovereignty Preservation: Each rollup keeps control over its own sequencing, fee markets, and execution environment while participating in cross-rollup coordination.
- Horizontal Scaling: Ethera coordinates actions across multiple rollups without collapsing execution into a single shared sequencer.
- Ethereum Alignment: Ethera's based architecture ties publisher selection to Ethereum's proposer set, inheriting Ethereum's security and decentralization properties instead of relying on a separate coordinator set.
How It Fits Into Ethera
The Shared Publisher works with the rest of Ethera's coordination model:
- Mailbox Contracts carry cross-rollup messages between participating chains.
- Two Phase Commit provides the commit-or-abort decision process.
- Universal Bridge uses this coordination model for asset transfers and settlement across rollups.
The Shared Publisher does not replace the mailbox layer or the participating rollup sequencers. Mailbox contracts handle message transport between chains, rollup sequencers evaluate and sequence their local execution, and the Shared Publisher coordinates the final commit-or-abort decision across the participating rollups.
How It Works
- Submission: A cross-rollup action is submitted as one coordinated payload across the participating chains.
- Local Evaluation: Each rollup evaluates its own part of the action and records any required cross-rollup messages through the mailbox layer.
- Message Availability: The mailbox system makes those messages available to the participating destination rollups so they can evaluate the dependent parts of the action.
- Coordination: The Shared Publisher collects the rollups' decisions through Two Phase Commit.
- Commit or Abort: If every participating rollup can proceed, the action is committed atomically. If any participating rollup cannot proceed, the coordinated action aborts.
- Settlement: The resulting cross-rollup state transition is published and settled through Ethera's Layer 1 settlement path.
Why It Matters
The Shared Publisher is what allows Ethera to coordinate cross-rollup execution without turning the network into one centrally sequenced system.
That distinction matters for two reasons:
- Composability: Applications can coordinate actions across multiple rollups as one atomic flow.
- Rollup Independence: Each rollup keeps its own local control while participating in shared cross-rollup execution.
It also matters for security and network design. Ethera does not require rollups to hand ordering power to a separate shared sequencer. Instead, the Shared Publisher coordinates only the cross-rollup decision process while publisher selection remains aligned with Ethereum.
The Shared Publisher also connects coordination with settlement. After a cross-rollup action reaches a commit decision, the resulting aggregated state transition is published through Ethera's Layer 1 settlement path, where ZK proof verification is part of the settlement process.