Vitalik's post-merge Ethereum blueprint 1 considers modifying consensus to increase finality speed

Vitalik wrote on 10/14 an article stating that since the launch of Ethereum, it has undergone many significant changes, with one of the most notable being "The Merge." This event marks Ethereum's transition from a Proof of Work (PoW) consensus mechanism to Proof of Stake (PoS), a long-awaited shift. As of October 2024, Ethereum has been operating as a PoS system for two years, demonstrating excellence in stability, performance, and decentralization resistance. However, despite the successful transition, there are still many areas that need further improvement. The report will explore the future possibilities of Ethereum's PoS design, focusing on technical improvements and potential development paths.

Vitalik's post-merge Ethereum blueprint 2: Aiming for 100,000 TPS, revitalizing Plasma for off-chain scaling, integrating the L2 ecosystem

Merge: A Milestone in Ethereum's Evolution

What is "The Merge"?

Vitalik explains that "The Merge" originally referred to Ethereum's crucial transition from PoW to PoS, ushering in a new chapter for the network. Ethereum's PoS system has demonstrated stability and efficiency since then, but challenges remain. The current focus is on improving certain technical aspects of PoS, such as speeding up block finality, lowering the entry barrier for validators, and enhancing system efficiency.

Challenges Post "The Merge"

Despite the successful transition to PoS, Ethereum still faces challenges, including the extended time required for block finality and the high 32 ETH staking requirement for validators, limiting broader participation. Efforts are underway to address these issues while upholding Ethereum's core principles, such as economic finality.

Single-Slot Finality and Decentralization of Staking

What is the Finality Issue?

One of the key areas Ethereum developers are exploring is reducing the time required for block finality. Currently, achieving finality across multiple epochs takes about 15 minutes. The high 32 ETH staking requirement poses a significant barrier, hindering broader participation. The goal is to shorten finality time to a single block slot and reduce the validator entry threshold to 1 ETH.

Note: In Ethereum, an epoch represents a time range where validator activities occur, with each epoch consisting of 32 slots. Each slot lasts for 12 seconds, meaning each epoch lasts approximately 6.4 minutes.

Dilemma

Vitalik explains that achieving the goals of shortening finality time and lowering staking requirements is challenging. To ensure economic finality, where the cost of block reversion is prohibitively high, each validator must sign off on blocks, which can make the process more time-consuming. While networks like Algorand use committee-based finality, applying this method hastily on Ethereum could expose it to a higher risk of 51% attacks.

Exploring Potential Solutions

Solution 1: Hardening

One proposed solution is to address this challenge by improving signature aggregation protocols. Technologies like zero-knowledge proofs (ZK-SNARKs) can help efficiently handle signatures from millions of validators, allowing Ethereum to improve speed while maintaining decentralization.

Solution 2: Orbit Committees

Orbit Committees offer another solution by distributing finality responsibilities to smaller randomly selected groups of validators. This can reduce the burden on node operators while maintaining a high level of economic finality critical for Ethereum's security. The Orbit Committees work by selecting a medium-sized committee from a larger pool of validators, reducing attack risks while maintaining efficiency.

Solution 3: Dual-Staking System

The dual-staking system introduces validators of different levels, with higher-level stakers playing a more critical role in finality. This approach can lighten the overall burden on validators while still allowing smaller validators to participate, but it also brings potential centralization risks.

Single-Slot Finality: The Most Promising Proposal?

How Single-Slot Finality Works

Single-slot finality will allow blocks to achieve finality within a single slot of 12 seconds or less, significantly enhancing user experience. By reducing the likelihood of blockchain reorganizations and accelerating transaction confirmations, it simplifies Ethereum's protocol for the benefit of the network and users. Achieving this requires modifications to the consensus mechanism, potentially giving Ethereum a competitive edge against other performance-focused blockchains.

Supported Proposals

Several proposals aimed at implementing single-slot finality have emerged, such as the "Horn" protocol focusing on improving signature aggregation and "Orbit SSF," which seeks to balance validator efficiency and economic finality. These proposals aim to maintain Ethereum's decentralization while making the system faster and more inclusive.

Addressing Decentralization Concerns

Lowering Validator Entry Threshold

One crucial goal is to reduce the minimum 32 ETH staking requirement. By allowing staking with just 1 ETH, Ethereum can democratize participation and increase the number of individual stakers. This measure can further decentralize the network by enabling more individuals to run their own validators without relying on large staking pools.

However, lowering the entry threshold and speeding up finality can increase node burdens, potentially squeezing out smaller validators from the network. Therefore, finding a balance between inclusivity and efficiency is crucial for the future success of Ethereum's PoS.

The Future of Ethereum: Beyond the Merge

Single Secret Leader Election (SSLE)

Another research area is the Single Secret Leader Election (SSLE), aimed at addressing the vulnerability of prematurely revealing the next block proposer's identity. This information could be exploited by attackers to launch denial-of-service (DoS) attacks against validators. SSLE adds an extra layer of security by concealing the proposer's identity until block generation.

Faster Transaction Confirmations

Research is also ongoing to shorten Ethereum's slot time, potentially reducing transaction confirmation time from 12 seconds to 4 seconds. Shorter confirmation times will enhance user experience, especially for decentralized finance (DeFi) applications and Rollups, making Ethereum more efficient and decentralized.

Vitalik believes that the transition to PoS was a significant achievement for Ethereum, but the journey is far from over. As developers continue to refine the protocol, the focus will remain on making the system more secure, efficient, and user-friendly to a broader audience. Through innovations like single-slot finality, Orbit Committees, and SSLE, Ethereum is advancing towards maintaining its position as a leading blockchain network while addressing challenges of decentralization, performance, and security.