The Ethereum 2.0 Altair Hard Fork is arriving this week. This is the first hard fork on the network and is relatively minor. Altair does introduce one big change though, light clients.

Note that the Altair upgrade follows with the ‘London’ fork on Ethereum. 

This article is only concerned with Ethereum 2.0 and will not go into the London fork.

In this article, we’re going to concentrate on light clients. We’ll give you a digestible introduction, focusing on the key details you need to know. 

First, let’s establish some context and look at why the Altair Fork is happening…

Why Is The Ethereum 2.0 Altair Hard Fork Happening?

The main aim is to allow Light Clients. With this, mobile phones or embedded devices will be able to verify the blockchain. They will not need to connect to an external provider. Altair will achieve this through sync committees.

Altair is also tightening Ethereum 2.0. Penalties are being increased, aligned with the initial Ethereum 2.0 protocol. The network had been softened to encourage early adoption. Altair will also boost block proposal rewards, giving successful validators a greater share.

Long term, Altair is part of the ‘The Merge’. That is, the alignment with the Ethereum network. Altair and London bring the two networks closer to convergence. This will move Ethereum to proof-of-stake and reduce energy consumption by a claimed 99.5%.

Ethereum 2.0 Light Clients: The Key Details

As mentioned above, light clients are the main aim of the Altair fork. They’re considered the flagship of the change. But what are light clients, and how do they work? 

Blockdaemon is the leading Ethereum 2.0 infrastructure provider. We’ve used our unrivalled knowledge and expertise to simplify the key details for you: 

What Are Light Clients?

Light clients are small nodes able to run on lower resource kit. For example, mobile or embedded devices. Altair will introduce light clients to Ethereum 2.0 for the first time. 

Light clients allow you to run a trust-minimized wallet on your phone. There would be no need to connect to the network via a 3rd party node or service. 

Light clients are made possible by sync committees.

What Are Sync Committees?

A sync committee is a group of 512 validators, randomly assigned by the Ethereum 2.0 network. A new committee is chosen every 256 epochs, roughly 27 hours.

This committee continually signs block headers for each new slot in the beacon chain. A light client can trust these headers to represent accurate and validated blocks. 

How Do Sync Committees and Light Clients Work Together?

With sync committees, the light client does not need to know the entire validator set or the full beacon chain. 

The light client only needs to know:

  • A previously validated block header
  • Members of the previous, current, and next committee. 

The light client can use this information, and Merkle proofs, to verify the beacon state.

Light clients can thus authenticate block signatures. With limited data and against a much smaller subset of validators. This reduces the amount of computational power needed to authenticate a header.

Sync Committee Membership offers Rewards… and Penalties 

The network rewards Sync committee members for consistent singing of the block headers. This will be 2/64 of the total perfect validator rewards. The network will penalise validators a similar amount if they fail to fulfil their duties.

If you’re selected as a committee member, you’ll get a 27-hour notice period. This should give you enough time to cancel any planned maintenance or downtime. 

Check out GitHub for more information on Light Clients.

Ethereum Altair Hard Folk: Light Clients & Sync Committees

Light clients are the main change in the Altair fork. They allow smaller devices direct access to the Ethereum 2.0 network.

Through sync committees and Merkle proofs, light clients need only a small amount of data. This means even mobile phones can operate as a small node on Ethereum 2.0.

Blockdaemon is the leading infrastructure provider for Ethereum 2.0 networks. We ensure our customers have 99.99% uptime, and we insure against slashing penalties.

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