Ethereum Foundation's latest AMA review: validator set, random number, DVT, technical direction

Original compilation: GaryMa Wu said blockchain

On July 12, the research team of the Ethereum Foundation conducted the 10th AMA on the reddit forum. Community members can post questions in the post, and members of the research team will answer them. Wu said that the relevant questions/technical points involved in this AMA are summarized and compiled as follows:

**1. Validator exit related: Allow the validator to withdraw the certificate from its execution layer (0x 01) to trigger the exit. If the balance is less than 16 ETH (slack work penalty or slashing event occurs), the validator will be kicked out of the agreement. Here Is the 16 ETH threshold too low? **

This is mainly related to the EIP-7002 draft. It is understood that Danny Ryan and other research developers jointly released the EIP-7002 draft, which aims to allow validators to withdraw credentials from their execution layer (0x 01) to trigger exit to the letter. marked chain. Since the validator has two keys, the active key and the withdrawal certificate, but currently, only the active key can initiate the validator exit, which means that in any non-standard escrow relationship, the holder of the withdrawal certificate cannot independently Opt out and begin the withdrawal process. To ensure that withdrawal tokens held by EOAs and smart contracts can control staked ETH without trust, this specification allows 0x 01 withdrawal tokens to trigger exits. This proposal will benefit the development of tracks such as liquid staking and distributed verification, further promote the decentralization of the beacon chain, and at the same time better manage risks, such as the loss of private keys, or the loss of DVT verifiers with most Shared key connections, etc.

2. Random number problem: RANDAO + VDF

RANDAO is a way to generate random numbers. Suppose there are 10 students in the class, and the teacher wants to randomly select a student to give him a reward. The selection method given by the teacher is that all the students give a random number at the same time, the teacher adds up the 10 random numbers obtained, and the last number obtained is the remainder of 10, and the remaining number is the student who should be selected. However, a problem can actually be found from the above RANDAO operation process. If a classmate cheats and gives random numbers to 9 classmates, then he can choose a number that is most beneficial to himself based on the random number information given by 9 classmates, so that the final result points to himself. Therefore, the effective operation of RANDAO requires the introduction of an anti-cheating mechanism, that is, a certain method is required to ensure that everyone gives answers at the same time. VDF also came in handy. The full name of VDF is Verifiable Delay Function. The important feature of this function is that the calculation process to obtain the result cannot be calculated in parallel, that is, it cannot be accelerated. However, after the result is obtained, the amount of calculation to verify the result is very small. VDF is realized by hash function, and the characteristic of slow calculation and fast verification of hash function is also consistent with the nature of VDF.

However, members of the research team said that the ultimate economics of trying to exploit this "last proposer" vulnerability may not be ideal, and such deception could seriously damage the validator's reputation.

**3. Are SSV (Secret Sharing Verifier) and DVT (Distributed Verifier Technology) "must" for Ethereum? **

With Ethereum staking exceeding 20%, facing the centralization risk of potential node operators, two research team members said that such technology may be a "must" solution in the short to medium term.

Justin Drake said that his recent thinking has partially changed, because in the long run, if One-shot signatures are implemented, the importance of these risk challenges will be significantly reduced. However, one-time signatures may take decades to achieve, so DVT will be a more effective solution in the short to medium term.

One-shot signatures are a special kind of cryptographic signature in which the private key can only be used to sign one message. It can solve many long-standing problems in the blockchain field, providing numerous advantages such as exit penalties, perfect finality, trustless liquidity staking, and more.

**4. The maximum effective balance: increasing the upper limit of the validator’s pledge (32 ETH), can reduce the number of validators in the network, so as to achieve faster transaction finality (single slot finality), such as: 1) 32 ETH The upper limit of , but the upper limit of the number of network verifiers; 2) Whether to consider the number of verifiers' attestations (attestations) into the voting weight. **

Option 1 would result in a marketplace for trading existing validator qualifications, introducing a potentially serious security risk.

Option 2 will change the security model of the protocol and will reduce the difficulty for attackers to reorganize the chain.

There has been a recent community proposal to increase the maximum active validator balance from 32 ETH to 2048 ETH to help reduce the growth of the active validator set.

**5. What is the current progress of SSLE/Single Secret Leader Election? **

Vitalik said that SSLE is still in the research stage. Since the non-secrecy of the Leader has not been proven to be a problem, the priority of SSLE will be relatively low.

ps: Single secret leader election, currently the proposers selected for each Slot of the beacon chain will be disclosed in advance, which makes them vulnerable to DoS attacks. The latest solution encrypts and hides this process, and only the proposer knows his identity, which can effectively mitigate potential risks.

**6. Is there any update on the current technical roadmap of Ethereum? **

Vitalik said that most of them are progressing as scheduled. Of course, there are also readjusted priorities. For example, in April, due to the Mev-Boost vulnerability, malicious verifiers attacked MEV Bots. At present, PBS within the protocol level will be improved (separation of proposers and builders) Concerns about potential security risks introduced by re-staking (re-staking) will increase the priority of optimizing and simplifying the solo staking experience.

In addition, in the general direction, what needs to be prioritized is to effectively help many things at the ecosystem level, such as ERC-4337 smart wallets need to achieve friendly cross-L2 and improve Gas efficiency.

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

The immediate composability of zk-rollups (which may not be possible between OP Rollups) does not depend on the completion of EIP 4844. The design space for composable coordination between zk-rollups is huge. For example, one of the possible solutions is to have a dedicated minimum zk-rollup as a liquidity aggregation.

**8. Justin Drake proposed an idea called Based Rollups to solve the sorting problem of Rollups (sorting in L1). Has it been applied yet? **

Based Rollups (or Rollups called L1 ordering) means that the ordering of the Rollup network occurs on the L1 it is based on (in most cases, the Ethereum network). More specifically, in the case of Ethereum, this means that the Seekers, Builders, and Proposers on the network all participate in the ordering of the Rollup network.

Based Rollups have many advantages over traditional Rollup networks that handle sorting by themselves. First, they depend on Ethereum for ordering transactions and thus benefit from Ethereum’s activity. When we discussed the risks of different Rollups above, we found that if the orderers or validators fail, many problems can arise, but for Based Rollups, unless there is a problem with the Ethereum network, there is no such risk. In addition, there are advantages such as decentralization and no need for tokens.

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

Some people may confuse and think that Based Rollups will use the memory pool shared with L1, but it is not, Rollups will have its own memory pool.

**9. Concerns about centralization risk for block builders? **

Justin Drake said that the current builder market is actually very centralized (see the main risk of builder centralization is censorship, and the current better solution is to auction some blocks, such as inclusion lists (Inclusion lists), proposer suffixes (Proposer Suffixes), amendments to proposer suffixes: pre-commitment and encrypted mempool, MEV destruction, etc.

**10. If the number of validators exceeds 1 million this year, will the main network be able to run stably? How many validators can the mainnet currently support? **

At present, the client team indicates that the number of verifiers that the main network can support is between 1 and 2 million. The developer community is also conducting related explorations. The next testnet, Holesky, will have 1 million verifiers.

**11. Will the Ethereum Foundation be dissolved? What will be the end of the Foundation? **

Justin Drake said that the Ethereum Foundation has no income, and some conferences are usually non-profit, and will not use the ETH in the treasury for pledge to generate income. If the Ethereum Foundation treasury is exhausted, funding could come from two sources:

● Public product financing infrastructure within the ecosystem;

● Relatively low Ethereum L1 budget;

**12. At present, there is no mature technical solution for the execution of cross-rollups transactions. What are your views and suggestions? **

Vitalik said that he does not think the use cases of synchronous cross-rollups transaction execution are high, and asynchronous cross-rollups transaction execution is acceptable and there are many use cases. Synchronous trade execution across rollups feels more like an esoteric area of definition, and if we figure it out, it will certainly improve market efficiency to some extent, but otherwise we can do without it entirely.

**13. If the performance of rollups falls into a bottleneck in the future, is it possible for the two-sharding in the previous stage of Ethereum to return to the stage? **

Justin Drake said that performing sharding does not provide more expansion. In addition, the bottleneck of Rollups is data rather than execution. We can actually regard each rollup network as an execution shard.

As long as the L1 EVM implements SNARKified (The Verge stage of the Ethereum roadmap), then Ethereum will have an enshrined rollup (a rollup that enjoys some kind of consensus integration on L1). It can also be said that Ethereum has an enshrined rollup at the L1 consensus level Perform sharding. Once the hard work of SNARKifying is done, it becomes relatively easy in the L1 EVM to expose the SNARK verification logic itself as EVM opcodes. In this way, an unlimited number of enshrined rollups can be realized. At the Ethereum consensus level, these enshrined rollups are like the execution sharding of the main network, with scalability and the same security as the main network.

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