Original translation: GaryMa Wu talks about blockchain

On July 12th, the Ethereum Foundation research team conducted their 10th AMA on the reddit forum, where community members could leave messages and ask questions that the research team members would answer. The following is a summary of the relevant questions/technical points discussed in this AMA, compiled by Wu:

1. Validator exit-related: Is the threshold of 16 ETH too low?

This is mainly related to the EIP-7002 proposal. It is understood that Danny Ryan and other research developers jointly released the EIP-7002 proposal, which aims to allow validators to withdraw from their execution layer (0x 01) to the beacon chain. Validators currently have two keys, the active key and the withdrawal certificate, but currently only the active key can initiate validator exits. This means that in any non-standard custodial relationship, the holder of the withdrawal certificate cannot independently choose to exit and initiate the withdrawal process. In order to ensure that withdrawal certificates held by EOAs and smart contracts can control the staked ETH without trust, this specification allows 0x 01 withdrawal certificates to trigger exits. This proposal will benefit the development of liquidity staking and distributed validation, further promote the decentralization of the beacon chain, and better manage risks such as private key loss or DVT validators losing connections with most shared keys.

2. Random number problem: RANDAO + VDF

RANDAO is a way to generate random numbers. Let's say there are 10 students in a class, and the teacher wants to randomly select one student to reward. The teacher's method is for all students to simultaneously provide a random number, the teacher adds up the 10 random numbers, takes the modulus of 10, and the remainder is the student to be selected. However, a problem can be found in the process of running RANDAO as described above. If a student cheats and provides a random number after the other 9 students have provided theirs, they can choose a number that is most beneficial to themselves based on the random numbers provided by the other 9 students, so that the final result points to themselves. Therefore, the effective operation of RANDAO requires the introduction of anti-cheating mechanisms, which means ensuring that everyone provides an answer simultaneously. This is where VDF comes into play. VDF stands for Verifiable Delay Function, and the important feature of this function is that the calculation process of obtaining the result cannot be parallelized, i.e., it cannot be accelerated. However, once the result is obtained, the amount of computation required to verify the result is very small. VDF is implemented through hash functions, and the slow calculation and fast verification characteristics of hash functions are consistent with the properties of VDF.

However, team members say that the ultimate economic benefit of exploiting this "last proposer" vulnerability may not be ideal, and such deceptive behavior could seriously damage the reputation of validators.

3. Are SSV (Shared Secret Validator) and DVT (Distributed Validator Technology) necessary for Ethereum?

With Ethereum's staking amount exceeding 20%, and facing the centralization risk of potential node operators, two team members believe that these technologies could be a "must" solution in the short to medium term.

Justin Drake, on the other hand, says that his recent thoughts have changed somewhat because in the long run, if one-time signatures are achieved, the importance of these risk challenges will significantly decrease. However, it may take decades to achieve one-time signatures, so DVT will be a more effective solution in the short to medium term.

One-time signatures are a special type of cryptographic signature where the private key can only be used to sign one message. They can solve many long-term issues in the blockchain field and provide numerous advantages such as removing penalties, perfect finality, and trustless liquidity staking.

4. Maximum effective balance: Increasing the upper limit (32 ETH) for validator staking can reduce the number of validators in the network, leading to faster transaction finality (single slot finality). For example: 1) Keep the upper limit of 32 ETH but limit the number of network validators; 2) Consider including the number of validator attestations in voting weights.

Option 1 would create a market for transactions with existing validator qualifications, introducing potential serious security risks.

Option 2 would change the security model of the protocol, reducing the difficulty of attackers reorganizing the chain.

Recently, there have been proposals in the community to increase the maximum effective validator balance from 32 ETH to 2048 ETH to help reduce the growth of active validator sets.

5. What is the current progress of Single Secret Leader Election (SSLE)?

Vitalik says that SSLE is still in the research stage, and its priority will be relatively low since the non-secrecy of the current leader has not been proven to be a problem.

Note: The current candidates elected for each slot in the beacon chain are publicly disclosed in advance, making them vulnerable to DoS attacks. The latest proposal encrypts and hides this process, so only the proposers know their identities, effectively mitigating potential risks.

6. Are there any updates to Ethereum's technical roadmap?

Vitalik said that most things are progressing as planned, although there are priorities that need to be adjusted, such as the prioritization of implementing protocol-level PBS (Proposer Builder Separation) due to the malicious validator attacks caused by the Mev-Boost vulnerability in April. Concerns regarding potential security risks introduced by re-staking will also prioritize the optimization and simplification of the solo staking experience.

In addition, in the general direction, priorities need to be placed on things that can effectively help many ecosystem-level matters, such as the friendly cross-L2 implementation of ERC-4337 smart wallets and improving gas efficiency.

7. Can EIP 4844 solve the fragmentation of liquidity between L1 and L2s?

The instant composability of zk-rollups (which may not be achievable between OP Rollups) does not depend on the completion of EIP 4844. There is a great design space for composability and coordination between zk-rollups. One possible solution is to have a dedicated minimal zk-rollup as liquidity aggregator.

8. Has Justin Drake's idea of Based Rollups been applied and implemented to solve the ordering problem of Rollups on L1?

Based Rollups (or L1-ordered Rollups) mean that the ordering of the Rollup network occurs on the L1 it is based on (typically the Ethereum network). Specifically, in the case of Ethereum, this means that searchers, builders, and proposers on the network are all involved in the ordering of the Rollup network.

Compared to traditional Rollup networks that handle ordering themselves, Based Rollups have many advantages. Firstly, they rely on Ethereum for transaction ordering, thus benefiting from Ethereum's activity. When discussing the risks of different Rollups, we found that many problems may arise if the orderer or the verifiers malfunction, but for Based Rollups, this risk does not exist unless there are issues with the Ethereum network. Additionally, they possess advantages such as decentralization and no token requirement.

One of the Layer 2 zkEVM projects, Taiko, will be released in the form of Based Rollups.

Some people may confuse Based Rollups with sharing the memory pool of L1, but in fact, Rollups will have their own memory pool.

9. Concerns about the centralization risks of block builders?

Justin Drake says that the current builder market is already quite centralized (see https://www.relayscan.io/). The main risk of centralization is censorship. The current solution is partial block auctions, such as inclusion lists, proposer suffixes, amendments to proposer suffixes: pre-commitment, encrypted memory pools, and MEV destruction.

10. Can the mainnet operate stably if the number of validators exceeds 1 million this year? How many validators can the mainnet currently support?

The current client team states that the mainnet can support approximately 1 to 2 million validators. The developer community is also exploring related options. For example, the upcoming testnet Holesky will have 1 million validators.

11. Will the Ethereum Foundation dissolve? What is the endgame for the foundation?

Justin Drake says that the Ethereum Foundation has no income, and even the conferences they hold are non-profit. They do not use the ETH in their treasury for staking or revenue generation. If the treasury runs out of funds, potential funding sources could be:

- Financing infrastructure for public products within the ecosystem

- Relatively low Ethereum L1 budgets

12. Currently, there is no mature technical solution for executing cross-rollup transactions. What are your thoughts and suggestions?

Vitalik believes that the use case for synchronously executing cross-rollup transactions is not very high, and asynchronously executing them is acceptable and has many use cases. Synchronous cross-rollup transaction execution feels like a niche area of definition. If we figure it out, it will definitely improve market efficiency to some extent, but otherwise, we can live without it.

13. If rollups' performance hits a bottleneck in the future, is it possible for Ethereum's previous Phase 2 sharding to make a comeback?

Justin Drake states that execution sharding does not provide more scalability. Additionally, the bottleneck for Rollups is data, not execution. In fact, we can consider each rollup network as an execution shard.

As long as the L1 EVM implements SNARKified (as mentioned in The Verge phase of the Ethereum roadmap), Ethereum will have an enshrined rollup (a rollup with some kind of consensus integration on L1), also known as an execution shard at the L1 consensus layer. Once the challenging work of SNARKifying is completed, it becomes relatively easy to expose the SNARK verification logic itself as EVM opcodes within the L1 EVM. This would enable an unlimited number of enshrined rollups, which act as execution shards of the main network at the Ethereum consensus layer, offering scalability and the same level of security as the main network.

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