In a detailed blog post dated December 27, Ethereum founder Vitalik Buterin outlined significant changes in Ethereum’s approach to proof-of-stake (PoS) verification following the Shanghai upgrade.
Ethereum currently supports many validators, enabling a broad base of individual and group participation, with approximately 895,000 validator entities. This is a key feature of Ethereum’s decentralized structure.
However, this model suffers from technical challenges, especially handling huge numbers of signatures. Today, approximately 28,000 signatures are needed to verify a block. This number is expected to reach 1.79 million after Sharding and Staking Finality (SSF).
The technological sacrifices to support such loads are significant. These include complex proof propagation mechanisms, the need for highly optimized BLS signature operations, lack of viable quantum-resistant alternatives, and increased slot times due to more subslots.
Buterin also highlights the systemic complexity and potential inefficiency of the current model in democratizing staking, as the minimum staking requirement of 32 ETH is financially prohibitive for many.
8,192 signatures
In response, Buterin proposes a pivot that reduces the number of signatures per slot to a manageable 8,192. He argues that these changes will open up the PoS design space, allow for technology simplification, improve security, and address quantum resistance issues.
Buterin criticizes the committee-based security approach used by other blockchains, highlighting the lack of accountability and deterrence against attacks. Ethereum, on the other hand, imposes severe penalties on attackers. Nonetheless, Buterin suggests that a low attack cost (1 to 2 million ETH) would be sufficient, and advocates a balanced solution that provides more benefits than a small set of validators while maintaining high penalties.
The blog post explores three approaches for implementing 8,192 signatures per slot in SSF.
- Decentralized Staking Pool: Focusing only on decentralized stake pools, potentially increasing minimum deposit amounts and limiting penalties, reducing trust in node operators.
- Two-tier staking: Set up a “heavy” layer for the major stakers involved in confirmation and a “light” layer for added security without a minimum stake requirement.
- Rotating Participation (Responsibility Committee): A hybrid approach where validators participate based on stake, ensuring safety through a carefully tuned set of validators.
Buterin’s conclusion emphasizes that sticking to 8,192 signatures would greatly simplify technical implementation and make Ethereum more accessible. The focus is then placed on selecting the most appropriate approach among the proposed options.
Security through Simplicity
Some users raised concerns in the comments about designing systems to be resilient against nation-state attackers, suggesting that reducing security budgets may not be enough. Buterin advocated “security through simplicity,” emphasizing the importance of simplicity in protocol design as a defense against a variety of attack vectors.
These proposed changes mark a pivotal moment in the continued development of Ethereum, emphasizing the ongoing balance of security, decentralization, and usability.