Ethereum co-founder Vitalik Buterin recently proposed significant changes to the Ethereum blockchain’s proof-of-stake (PoS) system. The core of his proposal is to reduce the number of signatures that verifiers have to process. Currently, Ethereum’s PoS mechanism includes approximately 895,000 validators processing approximately 28,000 signatures per slot, placing excessive load on the network.
The need for change: balancing decentralization and efficiency
Loading such a large number of validators and their associated signatures has major technical drawbacks. This limits quantum resistance, complicates forks, and makes signature scaling difficult via zero-knowledge proofs (SNARKs). Moreover, the minimum of 32 ETH to become a validator is still prohibitive to many, limiting widespread participation.
Buterin suggests that reducing the signature requirement from the current 28,000 to about 8,192 per slot could provide several benefits. This will simplify the consensus mechanism, make the blockchain more quantum-resistant, and keep the total amount of slashable ETH (1 to 2 million ETH) high, a mechanism for enforcing correct behavior among validators.
Exploring alternative approaches: decentralized staking pools, etc.
Buterin outlined three potential approaches to this change.
- Decentralized staking pools: This method involves increasing the minimum Ethereum required for staking and incentivizing small validators to form pools. This change reduces the number of individual validators.
- Dual-layer staking system: the ‘heavy’ layer requires a higher ETH stake (4,096 ETH) to participate in the final process, while the ‘light’ layer has no minimum requirements, striking a balance between security and accessibility.
- Rotating Validator Set: This approach includes a rotating set of 4,096 validators for each slot, adjusting the set during each slot to ensure network safety.
Security problem solving
Buterin also pointed out the limitations of the committee-based security model used in other blockchains. This model, which randomly selects a group of validators for each slot, lacks accountability in the event of a 51% attack. Ethereum’s current system of imposing severe penalties for such attacks is effective, but may be overly punitive. A balanced solution is needed that maintains a high slash-capable Ethereum while relinquishing the responsibilities of validators.
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