Blockchain's essential feature for good user experience is fast transaction confirmation times. Today's Ethereum has significantly improved compared to five years ago, thanks to stable block times after EIP-1559 and the PoS merger. Users can reliably confirm L1 transactions within 5-20 seconds, nearing credit card payment experiences. However, further enhancements are needed, especially for applications requiring sub-second latency. This article explores practical solutions to accelerate Ethereum's transaction confirmation.
Existing Ideas and Technologies Overview
Single Slot Finality (SSF)
Ethereum’s Gasper consensus uses a slot-and-epoch architecture. Every 12 seconds (a slot duration), a subset of validators votes on the latest block. Over 32 slots (6.4 minutes, one epoch), all validators vote once. These votes act as messages in a PBFT-like consensus algorithm, providing strict economic guarantees after two epochs (12.8 minutes), known as finality.
Recent dissatisfaction stems from:
(i) Complexity due to interactions between per-slot voting and per-epoch finality mechanisms.
(ii) The 12.8-minute wait time being too long.
SSF replaces this with a Tendermint-like mechanism where block N finalizes before block N+1 is proposed, retaining inactivity leaks for validator failures.
Challenges:
SSF implies each staker publishes two messages every 12 seconds, increasing blockchain load. Proposals like Orbit SSF aim to mitigate this.
Impact:
While SSF accelerates finality, it doesn’t reduce the 5–20-second user wait time.
Rollup Preconfirmations
Ethereum’s Rollup-centric roadmap delegates scalability to L2 protocols, which handle faster confirmations. L2s create decentralized sequencing networks where validators sign blocks every few hundred milliseconds, backed by staked tokens. Conflicts trigger penalties.
Current State:
Centralized versions exist, but decentralized Rollup sequencing progresses slowly. Shared preconfirmation mechanisms like Based Preconfirmations are proposed to unify L1/L2 preconfirmations.
Based Preconfirmations
This leverages Ethereum’s MEV-driven, complex proposers to offer standardized preconfirmation services. Users pay extra fees for guaranteed inclusion in the next block. Violations incur penalties.
Advantage:
Extends to Based Rollups, where L2 blocks are L1 transactions, enabling uniform preconfirmations.
Practical Observations
Post-SSF implementation (e.g., via Orbit), slot times may extend to 16 seconds. Combining Rollup/Based preconfirmations recreates an epoch-and-slot architecture.
Why?:
Approximate consensus requires fewer nodes and less time than economic finality. Current Ethereum divides 12-second slots into three sub-slots for block publishing, attestations, and aggregation. Optimizations could reduce this to 8 seconds or even 2 seconds with specialized nodes.
Conclusion:
Slot-and-epoch designs are inevitable but vary in efficiency. Less intertwined alternatives to Gasper merit exploration.
L2 Strategies
- Based: Align with Ethereum’s decentralization and anti-censorship values, acting as "branded shards" or experimenting with new VMs.
- Server-like: Enhance efficiency with STARK proofs, exit guarantees, and governance, retaining off-chain speed.
- Hybrid: Fast blockchains with ~100 nodes, relying on Ethereum for security (current common approach).
Future Focus:
The potential of Ethereum-native slot-and-epoch architectures (e.g., 1-second slots) could diminish hybrid solutions’ relevance. Key uncertainties remain around proposer complexity and novel designs like Orbit SSF.
FAQs
Q1: How does SSF improve Ethereum’s finality?
A1: SSF replaces multi-epoch finality with single-slot finality, reducing confirmation from 12.8 minutes to 12 seconds but doesn’t shorten initial wait times.
Q2: What are Based Preconfirmations?
A2: A protocol where users pay fees for guaranteed next-block inclusion, enforced by penalties, usable by L1 and Based Rollups.
Q3: Why adopt slot-and-epoch architectures?
A3: They balance speed (approximate consensus) and security (economic finality), adapting to node scalability and specialization.
👉 Explore Ethereum’s latest upgrades
👉 Learn about Rollup efficiencies