Ⅰ Briefly explain what “blockchain” means

Answer: 1. The connotation of blockchain

Blockchain is distribution New application models of computer technologies such as automatic data storage, point-to-point transmission, consensus mechanisms, and encryption algorithms.

2. Characteristics

1. Decentralization.

Blockchain technology does not rely on additional third-party management agencies or hardware facilities, and there is no central control. In addition to the self-contained blockchain itself, through distributed accounting and storage, each node realizes information self- Validate, deliver and manage.

2. Openness.

The foundation of blockchain technology is open source. In addition to the private information of the transaction parties being encrypted, the blockchain data is open to everyone. Anyone can query the blockchain data through the public interface. and develop related applications, so the entire system information is highly transparent.

3. Independence.

Based on consensus specifications and protocols, the entire blockchain system does not rely on other third parties. All nodes can automatically and securely verify and exchange data within the system without any human intervention.

4. Security.

As long as you cannot control 51% of all data nodes, you cannot arbitrarily manipulate and modify network data. This makes the blockchain itself relatively safe and avoids subjective and artificial data changes.

5. Anonymity.

Unless there are legal requirements, technically speaking, the identity information of each block node does not need to be disclosed or verified, and information transfer can be done anonymously.

II What is blockchain

[Definition]

Blockchain refers to the A technical solution for collectively maintaining a reliable database in a trustless manner. This technical solution allows any number of nodes participating in the system to calculate and record all information exchange data in the system for a period of time into a data block (block) through cryptographic algorithms, and generate the fingerprint of the data block for linking ( chain) and check the next data block, all participating nodes in the system jointly determine whether the record is true.

Blockchain is a general term for technical solutions similar to NoSQL (non-relational database). It is not a specific technology. Blockchain technology can be implemented through many programming languages ​​and architectures. . There are also many ways to implement blockchain. Common ones currently include POW (Proof of Work), POS (Proof of Stake), DPOS (Delegate Proof of Stake), etc.

The concept of blockchain was first introduced in the paper "Bitcoin: AIt is proposed in "Bitcoin: A Peer-to-Peer Electronic Cash System", the author is an individual (or group) who calls himself Satoshi Nakamoto. Therefore, Bitcoin can be regarded as the first application of blockchain in the field of financial payments.

[Popular explanation]

No matter how big the system or how small the website, there is usually a database behind it. So who will maintain this database? Under normal circumstances, whoever is responsible for operating the network or system will maintain it. If it is a WeChat database, it must be maintained by Tencent's team, and Taobao's database must be maintained by Alibaba's team. Everyone must think that this approach is natural, but this is not the case with blockchain technology.

If we imagine the database as a ledger: Alipay, for example, is a typical ledger, and any change in data is an accounting type. We can think of database maintenance as a very simple accounting method. The same is true in the world of blockchain. Everyone in the blockchain system has the opportunity to participate in accounting. The system will select within a period of time, maybe within ten seconds, or maybe ten minutes, to select the person with the fastest and best accounting during this period. This person will do the accounting, and he will combine the changes in the database during this period with Changes in the ledger are recorded in a block. We can imagine this block as a page of paper. After confirming that the record is correct, the system will link (chain) the data fingerprint of the past ledger to this paper, and then This piece of paper is sent to everyone else in the entire system. Then the cycle starts over and the system looks for the next person who can do the accounting quickly and well, and everyone else in the system gets a copy of the entire ledger. This also means that everyone in this system has exactly the same ledger. This technology is called blockchain technology, also known as distributed ledger technology.

Since everyone (computer) has exactly the same ledger, and everyone (computer) has exactly the same rights, there will be no problem due to a single person (computer) losing contact or going down. The entire system collapses. Since there are exactly the same ledgers, it means that all data is open and transparent, and everyone can see the digital changes in each account. Its very interesting feature is that the data in it cannot be tampered with. Because the system will automatically compare, it will consider the account books with the largest number of the same number as the real account books, and the small number of account books with different numbers as others are false account books. In this case, it makes no sense for anyone to tamper with their own ledger, because unless you can tamper with most of the nodes in the entire system. If the entire system has only five or ten nodes, it may be easy to do, but if there are tens of thousands or even hundreds of thousands of nodes, and they are distributed anywhere on the Internet,Unless someone controls most of the computers in the world, it is unlikely to tamper with such a large blockchain.

[Elements]

Combined with the definition of blockchain, we believe that it must have the following four elements to be called a public blockchain technology. If it only has the first three points elements, which we will consider as private blockchain technology (private chain).

1. Point-to-point peer-to-peer network (peer-to-peer power, physical point-to-point connection)

2. Verifiable data structure (verifiable PKC system, non-tamperable database)

3. Distributed consensus mechanism (solve the Byzantine generals problem and double payment)

4. Nash equilibrium game design (cooperation is an evolutionarily stable strategy)
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[Characteristics]

Combined with the definition of blockchain, blockchain will realize four main characteristics: decentralized, trustless, Collectively maintained (Collectively maintained), reliable database (Reliable Database). And the four characteristics will lead to two other characteristics: open source (Open Source) and privacy protection (Anonymity). If a system does not possess these characteristics, it will not be considered an application based on blockchain technology.

Decentralized: The entire network has no centralized hardware or management organization. The rights and obligations between any nodes are equal, and the damage or loss of any node will not affect it. operation of the entire system. Therefore, the blockchain system can also be considered to have excellent robustness.

Trustless: Each node participating in the entire system does not need to trust each other for data exchange. The operating rules of the entire system are open and transparent, and all data contents are also public. , therefore within the rule range and time range specified by the system, nodes cannot and cannot deceive other nodes.

Collectively maintain: The data blocks in the system are jointly maintained by all nodes with maintenance functions in the entire system, and these nodes with maintenance functions can be participated by anyone.

Reliable Database: The entire system will be divided into databases so that each participating node can obtain a copy of the complete database. Unless it can be controlled at the same timeMore than 51% of the nodes in the entire system, otherwise modifications to the database on a single node will be invalid and will not affect the data content on other nodes. Therefore, the more nodes and stronger computing power participating in the system, the higher the data security in the system.

Open Source: Since the operating rules of the entire system must be open and transparent, for the program, the entire system must be open source.

Privacy protection (Anonymity): Since nodes do not need to trust each other, there is no need to disclose their identities between nodes. The privacy of each participating node in the system is protected. protected.

Ⅲ What is blockchain in an easy-to-understand explanation and how to explain it

Blockchain is actually equivalent to a disintermediated database, which is composed of a series of data blocks. Each of its data blocks contains information about a Bitcoin network transaction, which is used to verify the validity of the information and generate the next block.

In a narrow sense, blockchain is a chain data structure that combines data blocks in a sequential manner in chronological order, and is cryptographically guaranteed to be inextricable. Tamper-proof and unforgeable distributed ledger.

In a broad sense, blockchain is actually a distributed infrastructure and computing method, which is used to ensure the security of data transmission and access.

Blockchain classification

Public

Public Block Chains (Public Block Chains) refer to: any individual or Any group can send transactions, and the transactions can be effectively confirmed by the blockchain, and anyone can participate in its consensus process. The public blockchain is the earliest blockchain and the most widely used blockchain. The virtual digital currencies of all major bitcoins series are based on the public blockchain. There is only one blockchain corresponding to this currency in the world. .

Consortium

Industry Block Chains (Consortium Block Chains): Multiple pre-selected nodes are designated within a certain group as bookkeepers, and each block is generated by all pre-selected nodes. Nodes jointly decide (pre-selected nodes participate in the consensus process), other access nodes can participate in transactions, but do not participate in the accounting process (it is essentially still managed accounting, but becomes distributed accounting, how many pre-selected nodes, how to decide each The bookkeeper of the block becomes the main risk point of the blockchain), and anyone else can conduct limited queries through the open API of the blockchain.

Private

Private Block Chains: Only use the general ledger technology of the blockchain for accounting. It can be a company or an individual, and it can be used exclusively. The write permission of the blockchain is not much different from other distributed storage solutions. (Dec2015) Conservative giants (traditional finance) all want to experiment with private blockchains, while public chain applications such as Bitcoin have been industrialized, and private chain application products are still being explored.

IV What exactly is blockchain and what are its uses

Recently, the word "blockchain" has appeared very frequently on the Internet. The word "blockchain" is very interesting. So what is "blockchain", how to explain "blockchain", and what kind of chain is "blockchain"?

If we want to know what “blockchain” is, we must first start with Satoshi Nakamoto.

In November 2008, Satoshi Nakamoto posted a research report on a secret cryptography review group, describing his new idea for electronic currency-Satoshi Nakamoto proposed : "I believe there is a currency that doesn't rely on credit, and I can't stop myself from thinking about it." Bitcoin was born.

Although we still don’t know who Satoshi Nakamoto is, we all know the famous Bitcoin and the recently popular word “blockchain”.

In professional terms, blockchain is a new application model of computer technology such as distributed data storage, point-to-point transmission, consensus mechanism, encryption algorithm, etc.

In the original English version of the Bitcoin white paper [2], the word blockchain does not actually appear, but chain of blocks is used. In the earliest Chinese translation of the Bitcoin white paper [3], chain of blocks was translated into blockchain.

What does it mean in human terms? In layman's terms, blockchain is a decentralized distributed ledger database.

Decentralization means removing the original data center.

Here is an example of decentralization: Alibaba’s servers support Alibaba’s daily data operations, including the Double Eleven that just passed. We were able to smoothly carry out flash sales of goods at zero o’clock. Largely thanks to the support of Alibaba servers.

All data generated by Alibaba’s daily activities are recorded on the server. So what will happen if Alibaba’s server encounters an accident? (For example, Alibaba's server was hit by a meteorite, causing the server to be damaged)

After the server is paralyzed, Alibaba's data will naturally be unable to be restored in time, which will result in Alibaba being unable to maintain daily operations in the short term. operations.

However, after adopting blockchain technology, a piece of data generated by Alibaba due to daily business will not only be recorded on Alibaba’s servers, but also on various servers around the world such as the Internet and Google. , so that even if Alibaba’s server encounters an accident, it will still not affect Alibaba’sWhen running, the data generated by Ali's daily activities will still be recorded on various servers around the world. This is the advantage and benefit brought by blockchain technology.

In other words, Ali's data was only recorded in Ali's server, and Ali's server was the center. Now every server in the world is synchronously recording the business that Ali has done, and Ali's server is the center. It is no longer the only center, this step achieves decentralization. The behavior of servers around the world recording Alibaba data simultaneously is called distributed accounting.

Now that we know what blockchain means, what kind of boundaries can blockchain bring to our lives? What fields may blockchain be used in in the future?

1. Blockchain technology is applied in the medical and health field. For example, Xiao Zhang’s family has a history of hereditary red-green color blindness. Xiao Zhang once went to Hospital A and had his red-green color blindness checked. Now Xiao Zhang is in City B and went to Hospital B for treatment. Now Hospital B can directly treat him in his own hospital. Xiao Zhang’s previous medical treatment status was found in the database, so Hospital B no longer needs to conduct repeated examinations on Xiao Zhang. This greatly saves medical resources for the hospital and saves medical expenses for repeated examinations for Xiao Zhang.

2. Blockchain technology is applied in the field of food safety. Nowadays, everyone is paying attention to food safety, and blockchain technology is applied to the field of food safety to carry out food traceability. First, we can label each vegetable and fruit with its own label, and then record the growth, maturity, pests and diseases of the vegetables and fruits in this label. The data in this tag can be simultaneously recorded in various data centers around the world through blockchain technology.

On the one hand, when people buy vegetables, they can directly check the growth status of the vegetables. On the other hand, when our country imports and exports vegetables, we can directly check the status of the imported and exported products. No more quarantine required.

IV How to explain blockchain in a popular way

Blockchain is a decentralized distributed ledger database. The advantage of this distributed ledger is that buyers and sellers can Direct transaction without any intermediary. Everyone has a backup, even if your copy is lost, it will not be affected.

If you have a ledger at home, let you do the accounting. In the past, your parents gave you your salary and asked you to record it in your account book. If you are greedy and want to buy something delicious in the meantime, the record in the account book may be missing by more than ten yuan, and no one else will know.

How to use blockchain to solve problems: If you use the whole family mobilization method to keep accounts, the above-mentioned problems will not exist, because you are keeping accounts, your father is also keeping accounts, and your mother is also keeping accounts. They are also keeping accounts. They can all see the general ledger. You can't change it, and neither can your parents. So your father who wants to buy cigarettes and you who want to eat can't do anything about it.

(5) Popular explanation of what blockchain is video news extended reading:

BlockchainApplication fields

1. Financial field

Blockchain has potential huge application value in financial fields such as international exchange, letters of credit, equity registration and stock exchanges. The application of blockchain technology in the financial industry can eliminate the need for third-party intermediaries and achieve direct point-to-point connection, thereby greatly reducing costs and quickly completing transaction payments.

2. Internet of Things and Logistics Fields

Blockchain can also be naturally combined in the Internet of Things and logistics fields. Through blockchain, logistics costs can be reduced, the production and delivery process of items can be traced, and the efficiency of supply chain management can be improved. This field is considered a promising application direction of blockchain.

3. Public welfare field

The data stored on the blockchain is highly reliable and cannot be tampered with, so it is naturally suitable for use in social welfare scenarios. Relevant information in the public welfare process, such as donation projects, fundraising details, fund flows, recipient feedback, etc., can be stored on the blockchain and transparently and publicly disclosed conditionally to facilitate social supervision.

4. Insurance field

In terms of insurance claims, insurance institutions are responsible for fund collection, investment, and claims settlement, and often have high management and operating costs. Through the application of smart contracts, there is no need for the policy holder to apply or the insurance company to approve it. As long as the claim settlement conditions are triggered, the insurance policy can automatically settle claims.

VI An easy-to-understand explanation of what blockchain means

Blockchain is a technology that has produced many applications, including all industries related to data and information. Bitcoin is one of the most well-known applications.

The popular explanation of blockchain is that if you buy a lipstick online, you first find the product you like and the seller's order, and then give the money to the intermediary platform. After the seller delivers the goods and the buyer confirms receipt of the goods, the intermediary platform will transfer the money to the seller. Because of trust issues, both buyers and sellers rely on intermediate platforms, and blockchain, as a decentralized distributed ledger database, focuses on removing this intermediate platform while solving trust issues at the same time.

In the blockchain, everyone has their own ledger to record everything that happens. If the seller takes the money but does not deliver the goods during the transaction, the record will be permanent and cannot be modified, and there is no need to exchange information with each other. In the blockchain world, the ledger of the person with the fastest and best quality records at the same time node will be selected to copy, send in series, and finally become thicker and thicker to form a block.

Since everyone in the blockchain world participates in bookkeeping, the lack of anyone’s bookkeeping will not affect the security and stability of everyone’s information. The rise of blockchain is based on trust issues, which are related to wealth security. This is the first thing to pursue.