Enhancing Effectiveness of Ethereum Rollups with a Byzantine Fault Tolerant Finality Layer

Abstract

Ethereum Layer 2 (L2) rollups improve scalability but expose a trade-off between fast sequencer soft finality and slow Layer 1 (L1) settlement finality, limiting latency-sensitive applications that require timely and durable guarantees on transaction ordering. We introduce a Byzantine Fault Tolerant (BFT) finality layer that extends existing rollup architectures without requiring L1 or rollup protocol changes. This layer provides deterministic transaction-level finality ahead of L1 settlement by committing to the sequencer's transaction order, bridging the gap between soft and hard finality. At its core, the layer uses a 1-chain variant of the Jolteon consensus protocol, adapted to the rollup setting where a single sequencer determines transaction ordering. Experiments show sub-second committee finalization latency and stable performance under Byzantine faults.