Rome Protocol: The Shared Sequencer using Solana

Liquidity fragmentation has been the main objection to the Ethereum rollup-centric roadmap, amongst other problems such as weakest-link security and interoperability. This is mainly because sequencers, where users submit transactions, are isolated for each rollup. Since rollups have no visibility of each other, this means that transactions and liquidity on one rollup cannot easily interoperate with another. That’s why we have seen shared sequencer networks such as Astria and Espresso gain traction recently.

A shared sequencer enables rollups to launch quickly, provides atomic composability for cross-rollup transactions, and preserves decentralization. A shared sequencer network is a necessity for secure, decentralized, and scalable blockchains.

Shared sequencers also provide economies of scale; and allow for superior MEV searching by removing the uncertainty around latencies for multiple sequencers, which can allow for more efficient MEV searching.

Why use SOL instead of restaked ETH? A shared sequencer can just use EigenLayer to leverage restaked ETH for security, right?

Using SOL provides several benefits that are otherwise either not possible or require investment, time, and testing to reach Solana's level of capability. We highlight a few of these benefits below by comparing three different approaches.

Rome Protocol will provide a shared sequencer network deployed on Solana as smart contracts.

Each rollup on the shared sequencer network will be represented by a Neon EVM deployment. By doing separate deployments of Neon EVM for each rollup, the state of the Neon EVM deployment will be identical to the state of the rollup. Since the states are identical, a transaction will revert on the rollup if and only if it reverts on the Neon EVM deployment.

The canonical fork of Solana is unlikely to miscalculate whether a transaction reverts since the economic stake of the Solana network ensures its correctness.

Transactions going through Rome Protocol's sequencer are secured by Solana L1 and confirmed on the Solana chain before submission to the base layer.

Rome Protocol ensures the atomic composability of related transactions via our Atomic Composability Layer.

Shared sequencers provide economies of scale as more rollups use the same sequencer. As it unlocks use cases across the rollup ecosystem, it would offer several fee-based services:

- Fair and efficient MEV auctions
- Bridge service to enable atomic bridge transactions
- Cross-rollup arbitrage and DEX transactions
- Atomic execution of transaction across rollups for liquidity (defragment liquidity)

Rollups have emerged as the clear winner in scaling Ethereum. This means we need to optimize the speed at which transactions can be processed, streamline the deployment of new rollups, and improve atomic interoperability between rollups.

As more rollups emerge, MEV searchers will incur greater cost in globally optimizing across all rollups with varying latencies. By leveraging the single Solana L1 as a sequencer for all rollups, MEV searchers can more efficiently capture arbitrage opportunities.

When cross-rollup bundles don't exist, MEV searchers incur the opportunity cost of not having atomic cross-rollup transactions as shown in the example above. Rome Protocol’s native support for arbitrage and bridging addresses this opportunity cost.

Using Solana as a shared sequencer solves the above problems across rollup stacks such as zkStack’s hyperchains. Native bridging addresses the need for trustless bridging. Using Solana for shared sequencing provides fast proof aggregation. This all can potentially unlock the power of the hyperbridge and proof aggregation across the fractal landscape of zkEVM, which is unique to zkSync.