Easily understand the concept of ETH2.0 sharding

There are a lot of technical discussions about Ethereum 2.0 now, but most articles fail to explain the basic concepts clearly, confusing readers.

Although ETH2.0 is very complex overall, the design ideas of basic concepts such as sharding and beacon chain are very simple and do not require much professional knowledge to understand.

Let's put aside the complex technical implementation details for now and describe the concept of sharding in very concise words.

Ethereum Address

Let's first look at the address format of Ethereum. Below is a typical Ethereum address, which I copied randomly from the browser.

0x506dDF5a547EaaE34bAE6Ff57c78B5aD50a6A1BF

All Ethereum addresses start with 0x, which means they use hexadecimal. From the third character on, each character is from 0 to F, with a total of 16 possibilities.

Classification

We start classification from the third character. If we use one character to classify 0 to F, we can classify them into 16 categories. If we use two characters, such as 00 to FF, we can classify them into 16^2 = 256 categories. If we choose three digits, we can classify them into 16^3 = 4096 categories.

(Let’s not consider some restrictions in the Ethereum address specification, such as capitalization, checksum, etc. Let’s only consider the idea of ​​sharding. If we consider the address design specification, the actual classification is much less.)

All accounts in the current Ethereum 1.0 are not treated differently according to the above letters. All addresses have the same status, including external accounts and contract accounts.

The same here means that Ethereum nodes, wallets, and various software will not classify addresses, and will treat them all equally. This includes Ethereum block packaging, which will not be sorted by address classification.

In the sharding design of ETH2.0, addresses will be classified according to the first few letters.

Sharding

The address design rules of ETH2.0 will be classified, and one type of address is a shard. This is the famous shard, it's that simple.

In the first phase, Ethereum 2.0 will have 64 shards, which means that only the 3rd and 4th characters of the address need to be selected for classification.

After classification by address, ETH2.0's nodes, wallets, and various software can treat transactions of different types of addresses differently based on block design.

After the addresses are classified, the blocks will be packaged according to the address classification. A block will only contain one type of address. And all these blocks with the same classification address together constitute an Ethereum shard.

definition

Now we can define the shards of ETH2.0.

First, sort the addresses by the first few letters.

Shards are all blocks that contain transactions from the same type of address, and the same shard only contains transactions from one type of address.

Cross-film

If addresses in a shard send coins to each other, it is very easy to handle. But what if transactions are sent across shards? This is where the beacon chain comes in.

We will talk about the beacon chain later. Here we briefly describe how the beacon chain helps different types of addresses communicate across shards.

For example, address 0x00 wants to send 1ETH to address 0x01.

Each shard block is a block that follows the beacon chain, a one-to-one relationship.

The method is that 0x00 first sends 1ETH to the beacon chain block of its own partition. The beacon chain has something called a state transition function. This state transition function will send this 1ETH to the beacon chain block of the 0x01 partition, and then forward it to the 0x01 address.

Additional Notes

My description above is very simple and can be understood without basic knowledge. I still want to emphasize that this is just a description of the idea of ​​sharding, and its implementation details are very complicated.

The reference material is here: https://eth.wiki/sharding/Sharding-FAQs It is in English and difficult to understand. If you are willing to read it word by word, you will understand it.