One article to understand the implementation of Ethereum 2.0 secret sharing verification node technology

Editor's Note: This article comes fromChain News ChainNews (ID: chainnewscom)Editor's Note: This article comes from

Chain News ChainNews (ID: chainnewscom)

Chain News ChainNews (ID: chainnewscom)

Third-party pledge service for Ethereum 2.0

Source: Ethos, 2018

As of now, there are already 120,000.00 Ethereum addresses holding 32 ETH, which is the minimum requirement to become an Ethereum 2.0 (hereinafter referred to as "ETH2") public chain verification node. Of course, not all current and future ETH holders have the technical ability or desire to operate their own validating client nodes and help and secure the Ethereum network.

Fortunately, potential stakers have the right to decide whether to run a validator on their behalf through a staking service provider. According to our large-scale survey, more than one-third of stakers indicated that they were interested in staking on ETH2 through third-party services. If that's what you mean, read below.

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In order to participate in the consensus discovery of ETH2 and obtain the corresponding rewards, the verification node needs to use the private key to sign the certificate and produce a block. If a participant does not plan to run any personal validator nodes and wishes to stake on ETH2, these operations will be performed by a third-party staking service provider.

It should be noted that although entrusting the private key of the verification node to the supplier can grant it the efficient unilateral operation control of the verification node, it may face the risk of a single point of failure. If the company encounters downtime, triggers penalties intentionally or unintentionally, or terminates system services early due to bankruptcy liquidation, the pledged capital will be at great risk.

Currently, exchanges with high user traffic such as Binance and Coinbase are in a very favorable position. They can use their existing customer scale and reputation to expand their existing business lines and provide their users with ETH2 staking services. Larger companies may also have sufficient economies of scale and alternative revenue streams to subsidize staking services below the market average in order to further capture greater market share compared to smaller providers.

If a particular company centralizes "delegated pledges" over a significant share of the entire network, this could pose a greater risk of scale to the entire network. Considering that infrastructure providers often operate the same infrastructure for multiple customers, security issues such as simultaneous downtime and coordinated attacks may arise. Also, since ETH2 has a “correlation penalty mechanism” built into the protocol, it can easily incur a triple penalty compared to when all existing validators were penalized at nearly the same time. If a staking provider, customer, or cloud provider (such as Amazon) accidentally goes offline or makes a huge mistake because of a large stake, the consequences of huge penalties are unimaginable.

Secret Sharing and Secure Multi-Party Computation

Before we dig into the benefits of Ethereum 2.0's secret-sharing validators, we first need to understand its basic mechanics. Secret computation relies on two fundamental primitives in cryptography.

The first basic primitive is secret sharing. Through the secret sharing mechanism, the secret (or private key) is split and distributed among different participants in a way that "each participant only holds a part of the secret (that is, the secret fragment)". Fragments cannot be used to recover secrets. In order to recover the secret, a predefined number (or threshold) of shards need to be assembled.

The second fundamental primitive is secure multi-party computation (MPC). MPC allows multiple participants to jointly compute a function with their inputs hidden in a privacy-preserving manner. Applying MPC to secret sharing can allow the distribution of secret fragments among participants, and generate shared computing output through distributed computing, without the need for a single device to recover the secret and perform calculations.

Ethereum 2.0 Secret Sharing Verification Node

Use BLS signatures, a signature scheme defined on elliptic curves (BLS12-381 for ETH2). BLS signatures have "accumulative" structural properties, which means that they are friendly to aggregation operations and support merging multiple signatures into one signature.

Thanks to this additional property, sharing private keys (eg using Shamir's secret sharing mechanism) allows signing messages without the need to reconstruct the secret or the full MPC. By using the threshold signature scheme, the verification node private key can be split into any number of private key fragments, and how many signature fragments are needed to calculate the complete BLS signature.

For example, user Alice wants to reduce the risk of her assets, and happens to be able to contribute to the security and resilience of the ETH2 network, she can decide to divide her private validator private key into three shares, and distribute each share to her chosen provider, and it is assumed that two-thirds of the signature fragments are required to reconstruct the complete signature. No single third-party provider will unilaterally control her validators, and there is no longer the risk of a single point of failure.

All will be the winners of the secret shared validator scheme.

Ethereum 2.0's Secret Sharing Validator Adds Value

for pledgers

Diversification of risk - achieved by eliminating unilateral control of validators and single points of operational failure. Furthermore, this scheme can be leveraged to implement strategies that reduce dependency penalties, e.g., selecting nodes from small service providers with lower risk of failure of the same type.

For Staking Service Providers

Reduced liability - The ETH2 protocol encourages validators (especially large ones) to reduce the likelihood that their validation service will fail at the same time as other validation services. Allowing operators to distribute their authentication services across multiple machines or even data centers mitigates this failure risk and associated liability.

Level playing field - small validators with simple signature policies behave very differently from larger service providers - opening up for mutually beneficial collaboration between providers of different sizes and ratios by offering secret shared validator services way.

for the network

• Enhanced Security Measures – Centralization creates potential risks and attack vectors for the network and its participants. Security directly impacts Ethereum's value as a new global settlement layer. Focusing on the development of secret-sharing validators provides a path to realistically achieve some of the decentralization and anti-correlation goals of the ETH2 protocol to the benefit of all stakeholders in the network.

• The underlying foundation of secret sharing validator implementations

• Going back to Joseph Chow's hype, the actual implementation of secret sharing validators on ETH2 will require:

• Secret Sharing Validator Client Specification

Implementation of secret sharing validator client

A standard for operating secret-sharing validators between different providersEnd-user friendly UX/UI to split private keys between different providersWith the official ETH2 testnet launching soon, it is time for the community to drive collective action to designate, implement, and adequately test secret-sharing validators prior to a large network launch.

With the support of the Ethereum Foundation, the PlatON team has completed the engineering delivery of designing a secure multi-party computing algorithm, which is implemented using the optimized SCALE-MAMBA framework, showing ideal feasibility and performance goals. This project focuses on the MPC implementation of the proof-of-custody scheme in ETH2. pleasedankrad@ethereum.org。

See Github