Introduction: Improving ETH2.0 validator experience with key splitting
Editor's Note: This article comes fromEthereum enthusiasts (ID: ethfans)Ethereum enthusiasts (ID: ethfans)
Ethereum enthusiasts (ID: ethfans)
, Author: Mara Schmiedt, translation & proofreading: Min Min & A Jian, reproduced by Odaily with authorization.
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Third-Party Staking Services on ETH 2.0
Currently, there are 120,000 Ethereum addresses holding the 32 ETH necessary to become an ETH 2.0 validator. Of course, not all ETH holders have the technical ability and willingness to run validator client nodes to protect the security of the Ethereum network.
Fortunately, would-be stakers have the option to delegate ETH to a "staking-as-a-service" provider or exchange to stake and run a validator node on their behalf. We conducted a large-scale survey, and more than 1/3 of the respondents expressed interest in entrusting third-party service providers for staking. If you are one of them, just read this article!
To participate in the ETH 2.0 consensus mechanism and receive rewards, validators need to use their validator private key to sign attestation and propose blocks. If you want to participate in staking without running the infrastructure yourself, the validator private key will be handed over to a third-party staking service provider for operation.
It should be noted that entrusting your validator private key to a certain company is equivalent to authorizing the company to unilaterally control your validator node. If the company goes down, triggers the forfeiture mechanism either intentionally or accidentally, or has to permanently exit the system due to bankruptcy, your funds may be lost (this is also a so-called "single point of failure" problem).
Exchanges with a large number of users, such as Binance and Coinbase, have obvious advantages. They can use their existing customer acquisition portals and reputation to expand their existing business types and provide ETH 2.0 pledge delegation services. Large companies may have large enough economies of scale and other revenue streams compared to smaller providers to subsidize staking services below the market average, or even implement "0 commissions" in order to attract users or capture a larger market share promotional activities.
If a certain company attracts a large number of clients so that its holdings account for a large proportion of the entire network, it may pose a great risk to the entire network. Given that infrastructure providers typically run nodes for multiple customers on the same infrastructure, simultaneous shutdowns and coordinated attacks are possible. In addition, due to the anti-correlation penalty structure built into the ETH 2.0 protocol, if you are penalized with many validators at the same time, the penalty you suffer may increase by 3 times. If a staking service provider, client, or cloud service provider (such as Amazon) with a large stake unexpectedly goes offline or triggers a slashing mechanism, the penalty will be heavier as a delegator than as a validator running independently.
Private key splitting and multi-party computation
Before we dive into the advantages of private key split validators, let's quickly review the basic mechanism of ETH 2.0 private key split validators. Private key calculation mainly relies on two core cryptography components.
The first element is secret sharing. The private key split mechanism means that a private key is divided and distributed to different participants, and each participant holds a part of the private key. The portion held by an individual cannot be used to reconstruct the private key. The private key can only be reconstructed by combining individual holdings that reach a predetermined number (threshold).
The second element is secure multi-party computation (MPC). MPC enables multiple participants to secretly compute a function using their input values. If we combine MPC with private key splitting, we can have private keys dispersed among different participants, who can use their input values to perform decentralized computations and generate private key split output values without the need for a single device Reconstruct the private key above.
Private Key Split Validators on ETH 2.0
ETH 2.0 uses the BLS signature mechanism defined on elliptic curves (ETH 2.0 uses BLS12–381). BLS signatures are polynomial, which means they support aggregation, combining multiple signatures into one.
For example, if Alice wants to spread the risk and contribute to the security and attack resistance of the ETH 2.0 network, she can decide to split her validator private key into three shares, distribute them to the service provider of her choice, and need 2/3 signature mechanism to reconstruct the complete signature. No single provider can unilaterally control TA's validator nodes, so no single point of failure is possible.
So, who is the winner of the private key split validator mechanism? everyone.
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For stakeholders:
Spread your risk! This mechanism can eliminate the risk of unilateral control and single point of failure of validator nodes. Additionally, this mechanism can be used to satisfy anti-collusion strategies, e.g., select nodes from small providers, reducing the probability of associated failures.
For staking service providers:
Lighten your responsibilities! The ETH 2.0 protocol incentivizes validators (especially large validators) to reduce the likelihood that their validator node will fail at the same time as other validator nodes. Allowing operators to spread their validator nodes across multiple hardware devices or even multiple data centers can reduce risk and liability.
Create a level playing field! Small verifiers with simpler signing policies may not behave in a way that is relevant to large verifiers - therefore, service providers of different sizes can reach mutually beneficial cooperation and gain benefits by providing private key split verifier services Proportion.
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For the entire network:
Enhanced security! Centralization creates potential risks and attack vectors for the entire network and its participants. Security directly affects Ethereum's value as a new global settlement layer. By focusing on the development of private key split validators, we can enhance the degree of decentralization of the system and achieve the anti-correlation goal of the ETH 2.0 protocol, so that all stakeholders in the network can benefit.
Implementation
According to Joseph Chow's popular science, the implementation of the ETH 2.0 private key split verifier mechanism must meet the following conditions:
Specification for private key split validator clients
Implementation of private key split verifier client
Standard for running private key split validators among different service providers
Provides an end-user friendly UX/UI to split private keys between different service providers
Since the official testnet of ETH 2.0 is about to go online, it is not a good time for the community to work together to standardize, implement and fully test the private key split validator mechanism before the mainnet goes live.
