区块链主要存储清算,区块链主要存储什么

❶ The most straightforward explanation of blockchain

In recent years, the term "blockchain" has become a hot topic, and news media have reported on it, but you may not know The understanding of blockchain is still in the foggy stage. Today we will unveil its mystery.

In fact, the essence of blockchain is very simple and can be explained in one sentence: decentralized distributed database.

The main function of the blockchain is to store information. Anyone can write information and read it at the same time, so it is a public database.

Characteristics of blockchain

Distributed database technology has long existed in the market, but the difference is that although blockchain is also a distributed database , but it has no administrator and is completely decentralized.

Decentralization is a disruptive feature of blockchain technology. It does not require a centralized agent and realizes a direct point-to-point interaction, enabling high-efficiency, large-scale, and information interaction without a centralized agent. way becomes reality.

However, without an administrator, everyone can write data into it. How can we ensure that the data is trustworthy? What should I do if I am changed by a bad person? The designers have already thought of this, which proves that blockchain is a truly epoch-making product.

Block

The blockchain is composed of blocks. Blocks are much like database records. Every time data is written, a block is created.

Each block contains two parts:

Block header (Head): records the characteristic value of the current block
Block body (Body): actual Data
The block header contains multiple characteristic values ​​of the current block.

Generation time
Hash of the actual data (i.e. block body)
Hash of the previous block
...
Every time in the system Each node has the latest complete database copy. Modifying the database of a single node is invalid because the system will automatically compare and consider the same data record that appears the most times to be true. At the same time, every step of the data record will be retained on the blockchain, and the information at each step can be traced.

Here, you need to understand what a hash is, which is necessary to understand the blockchain.

The so-called "hash" means that the computer can calculate a characteristic value of the same length for any content. The hash length of the blockchain is 256 bits, which means that no matter what the original content is, a 256-bit binary number will be calculated in the end. And it can be guaranteed that as long as the original content is different, the corresponding hash must be different.

For example, the hash of the string 123 is (hexadecimal), converted into binaryThe base is 256 bits, and only 123 can get this hash. (Theoretically, it is possible for other strings to get this hash, but the probability is extremely low and can be approximately considered impossible.)

Therefore, there are two important inferences.

Corollary 1: The hash of each block is different, and the block can be identified by the hash.
Corollary 2: If the content of the block changes, its hash will definitely change.

The immutability of hashes

Blocks and hashes have a one-to-one correspondence, and the hash of each block is for the "block header" (Head) computational. That is to say, the characteristic values ​​​​of the block header are connected together in order to form a very long string, and then the hash is calculated on this string.

Hash = SHA256 (block header)

The above is the calculation formula of block hash. SHA256 is the hash algorithm of the blockchain. Note that this formula only includes the block header and not the block body. In other words, the hash is uniquely determined by the block header.

As mentioned earlier, the block header contains a lot of content, including the hash of the current block body and the hash of the previous block. This means that if the content of the current block body changes, or the hash of the previous block changes, it will definitely cause the hash of the current block to change.

This is of great significance to the blockchain. If someone modifies a block, the hash of the block changes. In order for subsequent blocks to still be connected to it (because the next block contains the hash of the previous block), the person must modify all subsequent blocks in sequence, otherwise the modified block will be removed from the blockchain . Due to the reasons mentioned later, hash calculation is very time-consuming, and it is almost impossible to modify multiple blocks in a short period of time, unless someone controls more than 51% of the computing power of the entire network.

It is through this linkage mechanism that the blockchain ensures its own reliability. Once the data is written, it cannot be tampered with. This is just like history, what happened happened, and it can’t be changed from now on.

❷ Components of Blockchain

The components of Blockchain are as follows:

Openness: Blockchain The system data is open and transparent, and everyone can participate. For example, when renting a house, you can know the previous rental information of the house and whether there have been any problems. Of course, some personal private information is encrypted.

Autonomy: The blockchain adopts consensus-based specifications and protocols (such as a set of open and transparent algorithms), and then each node operates according to this specification, so that everything is completed by machines , there is no human element. This changes trust in people to trust in machines, and any human intervention has no effect.

Information cannot be tampered with:If the information is stored in the blockchain, it will be saved permanently and there is no way to change it. As for the 51% attack, it is basically impossible to achieve.

Anonymity: There is no personal information on the blockchain, because it is all encrypted and is a string of letters and numbers, so your various ID card information and phone number will not appear. Numbers are being resold.

❸ Where is the data in the blockchain stored?

The data in the blockchain all exists in the terminal or in the server. Because we are talking about blockchain, its user terminal can also be a server, and the server can also be a user terminal, so it is all stored on these devices.

❹ What structures does the blockchain consist of?

The blockchain is a chain storage structure formed by interconnecting blocks. The blocks are the data elements in the chain storage structure. The first block is called the genesis block.

General blocks include block header and block body. The block header contains the identification information of each block, such as version number, hash value, timestamp, block height and other information; the block body mainly contains specific transaction data.

❺ What are the main application areas of blockchain?

The main application areas of blockchain include: digital currency, transaction settlement of financial assets, digital government affairs, supply chain fields, Automobile industry, public service field, information security field, certificate storage and anti-counterfeiting data certification service and other fields. Blockchain is a new application model of computer technologies such as distributed data storage, point-to-point transmission, consensus mechanism, and encryption algorithms. It is an important concept of Bitcoin. It is essentially a decentralized database. At the same time, as the underlying technology of Bitcoin, it is a series of data blocks generated using cryptographic methods. Each data block contains The information of a batch of Bitcoin network transactions is used to verify the validity of its information (anti-counterfeiting) and generate the next block.

❻ What does blockchain mainly do?

Blockchain does not belong to any industry. Blockchain is a computer for distributed data storage, point-to-point transmission, consensus mechanism, encryption algorithm, etc. New application models of technology. In a narrow sense, blockchain is a chain-vertical data structure that combines data blocks in a sequential manner in chronological order, and is cryptographically guaranteed to be non-tamperable and non-forgeable. La distributed ledger.

❼ In what form is the data in the blockchain stored?

Blockchain is a distributed data storage, but the specific storage forms of different chains are different. Distribution The traditional storage technology does not store complete data in each computer, but separates the data and stores it in different computers. Just like storing 100 eggs, not in the same basket, but in different places, the total sum