Ethereum 2.0 terminology reveals why a beacon chain is needed

Abstract: From the so-called "software development hard work phase" of V God, to the current norm "freeze". After more than a year, the delivery schedule of Ethereum 2.0 has begun to get back on track.

In early July, Ethan Frank Foundation researcher Danny Ryan revealed that the Ethereum Serenity (quiet) zero phase has been “frozen”, which means that most of the upgrade changes have been completed to some extent.

From the so-called "software development hard work phase" of V God, to the current norm "freeze." After more than a year, the delivery schedule of Ethereum 2.0 has begun to get back on track . At the moment, we can begin to see the results of a lot of hard work put into research and development.

When I started to study Serenity (or Ethereum 2.0), the first thing that puzzled me was a lot of new terminology. What exactly is crosslink? Is slot a block? Is Attestor (cross-linking, cross-linking) and crosslink (cross-linking, cross-linking) the same thing?

The following is an attempt to describe the most commonly used terminology in Ethereum 2.0 for Ethereum users of the medium level of technology. Keep in mind that this is not an exhaustive list, but rather the most prominent details that you may have questions about.

The author of this article is Alex T, which draws on an article about the Ethereum beacon chain published by Ethereum researcher Ben Edgington at the end of October last year. Here I will add a supplement to this article in conjunction with Ben Edgington's article.

Ethereum 2.0 system architecture and delivery process

Before you understand the beacon chain and more technical terms, you need to understand the system architecture of Ethereum 2.0.

twenty three

As shown in the figure, from the top down, the Ethereum 2.0 system architecture is divided into three phases, from the POW backbone to the beacon chain, followed by the fragmentation chain and the VM layer (virtual machine layer). This can also be used as a development and delivery roadmap for Ethereum 2.0.

In February 2018, this roadmap was drawn in the PPT of Hsiao-Wei Wang, when Ethereum was still in the process of developing the Ethereum 1.0, the POW main chain, which was also separated from the later Constantinople hard fork. One year.

To date, the specification code for the beacon chain has been frozen and is scheduled for release on January 3, 2020. The work of fragmentation and Ethereum virtual machines has also begun.

The following is an overview of the three phases and functions of Ethereum 2.0:

Stage 0 – Beacon Chain

Manage certifiers and benefits (stakes)

Organize the Election Committee and develop block proposers for each shard

Apply consensus-consistent rules

Reward and punish/cut the verifier

Stage 1 – Fragmentation

Building slice chains and blocks

Anchor (cross-link) the tile to the beacon chain

Phase 2 – Execution Environment

Virtual machine execution based on eWASM. Every shard.

Trading ability

Ability to run and interact with smart contracts

Cross-slice communication

The following are important terms that appear in Ethereum 2.0:

Beacon Chain

A new POS chain that injects vitality into the entire Ethereum 2.0 system and is responsible for directing all participants in the coordination system.

Beacon block

Consensus layer for all transactions

Management verifier

Implement rewards and punishments

Provide random numbers to prevent block proposers from cheating in random number systems

Anchoring points by registering their status on the beacon chain as a shard to facilitate cross-sliced ​​transactions

It is worth mentioning that although the beacon chain management consensus algorithm and cross-chip communication, but communication is limited, too much communication will put too much pressure on the beacon chain. Therefore, the communication interval is 6 minutes. Every 6 minutes, each fragment can find the hash value of other fragments; the user and the application operate and run on different fragments.

In short, the beacon chain is responsible for commanding the rest of the system, and each participating node maintains its own local beacon chain to synchronize with other nodes.

Shards (shards)

There are 1024 parallel slice chains

Semi-independent chain, including sliced ​​blocks

The status of the tile is periodically recorded on the beacon chain by cross-linking

Once the block on the beacon chain is completed, the included fragment blocks in Crosslinks are considered complete.

Each shard has a validator committee to verify the block

Crosslinks (crosslinking, cross-linking)

A summary of the sharding states, connecting the entire sharding system together, anchoring each shard to the beacon chain as the spine

Reference only the fragments in the beacon chain

The current state of each shard (ie, the "combined data root") will be periodically recorded in the beacon chain to achieve cross-linking. When a certain block of the beacon chain is finalized, the corresponding fragment block is also considered to be finalized, and other fragments can rely on the determined slice for cross-slicing transactions.

Slot (time slot)

Slot is a block authentication proposed by the block proposer over a period of time, not a block. Unlike the POW's out-of-block time irregularity, Ettafang 2.0 has the same block time, which generates a block (can be changed) every 16 seconds, and this 16-second cycle is called Slots.

Slot may be empty

Slot is filled by certified blocks


In the POW chain of Ethereum 1.0, every 30,000 blocks is an epoch.

In the POS chain, Epoch contains multiple slots (currently 64), after which the validator will reshuffle in the committee.


A user who stores 32eth and runs a validator node in a validator storage contract (the node sends a deposit (32 Ethereum) to a set of certifiers by issuing a contract to a POW chain (ie the current Ethereum main chain))

These nodes can be inactive (not yet running as actual validators), active (authenticated), suspended (selected as a validator but stuck in the input queue), and quit (no longer wish to verify and Was stuck in the exit queue), but only active verifiers will participate in the Ethereum 2.0 agreement and can join the committee to vote.

Block Proposers (block proposer)

A random verifier of the beacon chain selection used to propose blocks for verification/authentication. At each stage, the selected block proposer is developed for each shard

The selected beacon chain block proposer will collect the protocol votes (authentication) of the beacon chain verifiers from the previous block and include those votes in the block issued by the verifier.

When everything is working, the slot should have a proponent, and the shard should have 16 proponents.

Attestations (certification)

Vote on the validity of a tile or beacon chain


The random verifier group (beacons & shards) selected by the beacon chain to verify block validity, ensuring which blocks constitute the true history of the entire chain.

The goal is to have at least 128 verifiers per committee. In addition, the beacon chain will assign a smaller sub-committee to each shard, and be responsible for confirming that the shard's proponent is acting properly when appropriate.


Base currency of the beacon chain

Initially will be obtained from the reward and lock ETH1 in the validator deposit contract

Validator Deposit Contract

Smart contract on the POW chain (in our case Ethereum Mainnet)

Once the ETH1 funds are locked in this smart contract and the event log is sent, it should be read by the beacon chain, and the same number of ETH2 should be assigned to the account that is now considered a validator.

This mechanism may change in the future

Before the end of the second phase, transferring ETH1 to ETH2 is a one-way street and cannot retrieve ETH1, but there is an exit to sell your stake.


Compile: Sharing Finance Neo