画图说明什么是区块链技术,画图说明什么是区块链的概念

1. What is blockchain

[Definition]

Blockchain refers to the method of decentralization and trustlessness A technical solution for collectively maintaining a reliable database. This technical solution allows any number of nodes participating in the system to calculate and record all information exchange data in the system over 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 and 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 proposed in the paper "Bitcoin: A Peer-to-Peer Electronic Cash System", written by the self-proclaimed Satoshi Nakamoto ( 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: for example, Alipay is a typical ledger, and any change in data is accounting. 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 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 completely equal rights, the entire system will not be affected by a single person (computer) losing contact or going down. system breakdown. 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 in any corner of the Internet, unless someone can control most of the computers in the world , otherwise it would be unlikely to tamper with such a large blockchain.

2. What is the meaning of blockchain?

Blockchain is a computer technology based on distributed data storage, point-to-point transmission, consensus mechanism, encryption algorithm, etc. New application models.

Blockchain 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 cryptographic methods related to each other. Each data block generated contains a batch of Bitcoin network transaction information, which is used to verify the validity of the information (anti-counterfeiting) and generate the next block.

(2) Draw a picture to explain what is a blockchain. Extended reading:

Types of blockchains

1. Public area Blockchain

Public BlockChains means: any individual or group in the world can send transactions, and the transactions can be effectively confirmed by the blockchain, and anyone can participate in its consensus process. .

Public blockchain is the earliest blockchain and the most widely used blockchain. The virtual digital currencies of all major bitcoins series are based on public blockchains. There is only one such blockchain in the world. The blockchain corresponding to the currency.

2. Consortium (Industry) Blockchain

Industry Blockchain (ConsortiumBlockChains): Multiple pre-selected nodes are designated as bookkeepers within a certain group. Each block The generation is jointly decided by all pre-selected nodes (the pre-selected nodes participate in the consensus process), and other access nodes can participate in transactions.

But don’t worry about the accounting process (essentially still managed accounting, it just becomes distributed accounting, how many pre-selected nodes, how to decide eachThe bookkeeper of each block becomes the main risk point of the blockchain), and anyone else can conduct limited queries through the open API of the blockchain.

3. Private Blockchain

Private Blockchains (PrivateBlockChains): Only use the general ledger technology of the blockchain for accounting. It can be a company or an individual. With exclusive write access to the blockchain, this chain is not much different from other distributed storage solutions.

Traditional finance is trying to experiment with private blockchains, while public chain applications such as Bitcoin have been industrialized, and private chain application products are still being explored

3. What is a blockchain? Blockchain

Blockchain is a new application model of computer technology such as distributed data storage, point-to-point transmission, consensus mechanism, and encryption algorithm. Blockchain is an important concept of Bitcoin.

It is essentially a decentralized database, and as the underlying technology of Bitcoin, it is a series of data blocks generated using cryptographic methods. Each block of data contains a The information of batches of Bitcoin network transactions is used to verify the validity of its information (anti-counterfeiting) and generate the next block.

(3) Draw a picture to explain what blockchain is. Extended reading

Characteristics of blockchain:

1. Deposit certificate

The "non-tamperable" feature of blockchain provides a solution to the problem of "certificate storage" in economic and social development. As long as the authenticity of the on-chain information and data can be ensured, the blockchain can solve the problem of "storage" and "certification" of information.

For example, in the field of copyright, blockchain can be used to store electronic evidence, which can ensure that it is not tampered with, and can link original platforms, copyright bureaus, judicial agencies and other parties through distributed ledgers. The banquet greatly improves the efficiency of Yinxin Bank in handling infringements.

2. Sharing

The "distributed" characteristics of the blockchain can break through the "data barriers" between departments and achieve information and data sharing. Different from centralized data storage, the information on the blockchain will be distributed to each node through point-to-point broadcasting, and all information can be "truthfully recorded" through "whole network witness".

4. What is blockchain

Blockchain is essentially a decentralized database. It is a new application model of distributed data storage, point-to-point transmission, consensus mechanism, encryption algorithm and other computer technologies.

The characteristics of blockchain are as follows:

Decentralization: Because of the decentralization of blockchain, it can help peer-to-peer transactions, so whether you are trading or exchanging funds, None require third-party approval. 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, each node realizes self-verification, transmission and management of information through distributed accounting and storage. Decentralization is the oldest block chain in the areaThe most prominent and essential features.

Anonymity: Unless required by legal regulations, technically speaking, the identity information of each block node does not need to be disclosed or verified, and information transfer can be carried out anonymously. The anonymity feature of blockchain protects user privacy to a certain extent.

However, the anonymity of blockchain is also quite controversial, because it plays an important protective role in people's transactions and privacy, and also provides a "protective umbrella" for some illegal and criminal activities.

5. Illustration of what is blockchain

Blockchain is so popular that it has begun to affect my life. I don’t even want to understand it. Let’s take a look today. What is blockchain.

Structure of this article:

As its name suggests,
A blockchain is a chain composed of a set of blocks.
A block is a block of information that contains information. , the chain also contains information.

Blockchain technology was first developed by a group of researchers in 1991 to time-stamp digital documents so that these documents cannot be tampered with. It essentially played no other role after that, until 2009, when Satoshi Nakamoto used blockchain technology to create the digital cryptocurrency Bitcoin.

A blockchain is a distributed ledger that is completely open to everyone. It has a very interesting property: once certain data is recorded in a blockchain, the data is very It is difficult to change.

Let’s take a look at the composition of a block:

Each block contains some data, the hash value of this block, and the hash value of the previous block. Hope value.

The data saved in the block is related to the type of blockchain. For example, the blocks in the Bitcoin blockchain save relevant transaction information, including sellers, buyers, and transaction Bitcoins. quantity.

Each block contains a hash value. The hash value is used to identify a block and all the content it contains, and it is unique, like a fingerprint. Once a block is created, its hash value is calculated accordingly. If you change something in the block, the hash value will change. If the fingerprint of a block changes, it will no longer be the previous block.

The third element contained in the block is the hash value of the previous block. This element allows links to be formed between blocks and makes the blockchain very secure.

Suppose we have a blockchain containing 3 blocks
Each block contains its own hash value and the hash value of the previous block
Block No. 3 points to block No. 2 , Block No. 2 points to Block No. 1
Block No. 1 is a bit special, it cannot point to the previous block, because it is the first
We call Block No. 1 the genesis area piece.

Now suppose we tamper with the second block
This will cause the hash value of the second block to change
This will then cause block 3 and 3 All subsequent blocks connected to the block number become illegal
Because the previous block number they store now becomes illegal
So changing one block alone will jointly make all subsequent blocks The content becomes invalid.

But to prevent tampering, hashing is not enough
Because today’s computer computing speed is powerful enough and can calculate thousands of hash values ​​per second
This way You can tamper with a block and recalculate the hashes of other blocks, making your block legal again.

So in order to reduce this risk, the blockchain also uses a technology called proof of work
This is a mechanism that slows down the creation process of new blocks
In the Bitcoin area In the blockchain, it takes about 10 minutes to complete the required proof of work and add a new block to the blockchain
This mechanism makes the tampering of the blockchain more difficult
because once it is tampered Once a block is obtained, the proof of work of all subsequent blocks needs to be recalculated.

Therefore, the security of blockchain technology mainly comes from hash value and workload proof mechanism.

Blockchain also has a mechanism to protect its own security, which is distributed
Compared to using a centralized entity to manage the blockchain network, blockchain uses A peer-to-peer network that anyone can join
When someone joins this network, he will get a copy of the entire blockchain
This person can use this to verify that all The blocks are still legal and untampered, that is, different nodes can use this to verify each other.

When someone creates a new block,
the new block is sent to everyone on the network.
Everyone then verifies the block to ensureEnsure that this block has not been tampered
If everything is verified to be correct, then everyone can add this new block to their own blockchain
We can call it , everyone on the network reached a "consensus".

All nodes in the blockchain network reach a consensus
They agree on which blocks in the network are legal and which are illegal
Those blocks that have been tampered with will will be rejected by other users on the network
So, to successfully tamper with a blockchain, you need to tamper with all blocks on the blockchain
Recomplete the proof of work for each block and control More than 50% of the users in the blockchain network
Only in this way will the block you tamper with will be recognized by everyone
It can be said that this is basically impossible to do!

Blockchain technology itself is also constantly developing
For example, a later technological improvement is called smart contracts
Smart contracts are simple programs stored on the blockchain
br /> It can automatically execute based on the conditions recorded in the contract. As long as the conditions are met, transactions will be automatically completed in accordance with the contract
For example, automated Bitcoin transactions can be realized under specific conditions.

Learning materials:
https://www.youtube.com/watch?v=SSo_EIwHSd4

6. What does blockchain mean?

Blockchain, an important concept of Bitcoin, is essentially a decentralized database and is the underlying technology of Bitcoin. It is a series of data generated using cryptographic methods. Block, each data block contains a batch of Bitcoin network transaction information, which is used to verify the validity of its information (anti-counterfeiting) and generate the next block.

Blockchain is a new application model of computer technology such as distributed data storage, point-to-point transmission, consensus mechanism, and encryption algorithm.

2. In order to realize the great leap forward development of blockchain finance, in order to promote the new development of China’s economy, accelerate the circulation of global assets, and realize the renaissance that generations have been striving for. dream.

Puyin Group held the Puyin Blockchain Finance Guiyang Strategy Release Ceremony in Guizhou on December 9, 2016. At the meeting, the blockchain will realize the digital circulation of assets and the blockchain financial transaction model. , and discuss the application of blockchain services and social public industries.

7. Comic illustration: What is blockchain

Comic illustration: What is blockChain

What is blockchain?
Blockchain, English Blockchain, is essentially a decentralized distributed database. Anyone can become a node of this huge network as long as they set up their own server and connect to the blockchain network.
Since the blockchain is essentially a database, what exactly is stored in it? Let’s take a look at the basic unit of blockchain: Block.
A block is divided into two parts:
1. Block header
The block header stores the header information of the block, including the hash value (PreHash) of the previous block. The hash value of the block body (Hash), the timestamp (TimeStamp), etc.
2. Block body
The block body stores the detailed data (Data) of this block. This data contains several rows of records, which can be transaction information or some other information.
What does the hash value just mentioned mean?
Everyone must have heard of MD5. MD5 is a typical hash algorithm that can convert a string of plaintext of any length into a string of fixed length (128 bits). This string is the hash value.
In our blockchain, a more complex hash algorithm called SHA256 is used. After a series of complex calculations, the latest data information (such as transaction records) will eventually be converted into a 256-bit hash value string through this hash algorithm, which is the Hash in the block header. The format is as follows:

Blocks and Hash have a one-to-one correspondence, and Hash can be regarded as the unique identifier of the block.
How are different blocks related to each other? Rely on Hash and PreHash to associate. The PreHash value of each block is equal to the Hash value of the previous block.
Why do we need to calculate the hash value of the block?
Since the blockchain is a chain structure, there must be a head node (the first block) and a tail node (the last block) of the chain. Once someone calculates the hash value of the latest data in the blockchain, which is equivalent to packaging the latest transaction records, a new block will be created and connected to the end of the blockchain.
The Hash of the new block header is the hash value just calculated, and the PreHash is equal to the Hash of the previous block. The data in the block body stores the transaction records before packaging, and this part of the data information has become unmodifiable.
This process of calculating Hash values ​​and creating new blocks is called mining.
The server used for massive calculations is called a mining machine.
The workers who operate calculations are called miners.
What is so difficult about calculating hash values? Let’s give the most basic explanation. The formula for calculating the hash value is as follows:
Hash = SHA-256 (Hash of the last block + basic information of the new block + transaction record information + random number)
Among them, the transaction record information is also a string of hash values, and its calculation involves a data structure Merkle Tree. Interested friends can check the relevant information, we will not introduce it for now.
The key computational difficulty here lies in the generation of random numbers. In order to increase the difficulty of Hash calculation, the wretched inventor of the blockchain requires that the first 72 bits of the Hash result must be 0. This probability is too small.
Since (the Hash of the last block + the basic information of the new block + the transaction record information) is fixed, whether the Hash that meets the requirements can be obtained depends entirely on the value of the random number. Miners must go through massive calculations and repeatedly generate random numbers in a general attempt to "get lucky" before they can get the correct Hash and successfully mine.
At the same time, the block header also contains a dynamic difficulty coefficient. When the world's hardware computing power becomes faster and faster, the difficulty coefficient of the blockchain will also increase, making the entire network capable of completing the task every 10 minutes on average. A new block is generated.
Friends, do you understand how difficult mining is? It should be added that different blockchain applications are different in details. The mining rules described here take Bitcoin as an example.
Applications of Blockchain

The concept of Bitcoin (BitCoin) was first proposed by Satoshi Nakamoto in 2008, and then based on this idea, open source software and P2P built on it were designed and released. network. Bitcoin is a P2P form of digital currency. Peer-to-peer transmission means a decentralized payment system.
What is a P2P network?
Traditional currencies are uniformly issued by the central bank, and all personal savings are uniformly managed by banks. This is a typical centralized system.
Bitcoin is deployed on a decentralized network composed of many peer nodes around the world. Every node is qualified to record and issue this digital currency.
As for the underlying data storage of Bitcoin, it is based on blockchain technology. Each transaction in Bitcoin corresponds to a row in the block data. A simple diagram is as follows:
Each row of the transaction record contains a timestamp, transaction details, and digital signature.
The table is only for ease of understanding. The actual stored transaction details are anonymous, and only the wallet addresses of the payer and payee are recorded.
As for digital signatures, they can be understood as anti-counterfeiting marks for each single transaction, generated by an asymmetric encryption algorithm.
Next let’s talk about the rewards of Bitcoin miners:
The Bitcoin protocol stipulates that miners who mine new blocks will receive rewards. Starting from 2008, it is 50 Bitcoins, and then halved every 4 years. , currently 12.5 in 2018Bitcoin. The new Bitcoins in circulation are all born in this way. No wonder everyone is so eager to mine Bitcoins!
Advantages and Disadvantages of Blockchain
Advantages of Blockchain:
1. Decentralization
Blockchain does not rely on a central node. The data of the entire system is All peer nodes in the entire network are jointly maintained and can store and verify data. In this way, unless the attacker hacks more than half of the nodes in the entire network, the entire system will not be destroyed.
2. Information cannot be tampered
The data in the block cannot be tampered with. Once the data is tampered with even a little bit, the hash value corresponding to the entire block will change accordingly, and it will no longer be a valid hash value, and the subsequent linked blocks will also be broken.
Disadvantages of blockchain:
1. Excessive consumption of energy
To generate a new block, a large amount of server resources must be used to perform a large number of unnecessary trial calculations, which seriously consumes electricity.
2. Network delay of information
Take Bitcoin as an example. Any transaction data needs to be synchronized to all other nodes. The synchronization process will inevitably be affected by network transmission delay, resulting in a long time consuming.
A few additional points:
1. Part of the content of this comic refers to Ruan Yifeng’s blog post "Blockchain Introductory Tutorial". I would like to thank this great master for his popular science.
2. Due to limited space, the knowledge about Merkle Tree and asymmetric encryption has not been discussed in detail for the time being. Interested friends can check the information for further study.

8. What is blockchain

Blockchain is a new application model of computer technology such as distributed data storage, point-to-point transmission, consensus mechanism, and encryption algorithm. Simply put, blockchain is a decentralized distributed ledger database.

The meaning of data storage:

Data storage is a temporary file generated during the processing of data flow Or the information you need to find during processing. Commonly used storage media are disks and tapes. How storage is organized varies depending on the storage medium. Data on the tape is only accessed in sequential file mode; on the disk, it can be accessed sequentially or directly according to the usage requirements.

The data storage method is closely related to the organization of data files. The key is to establish the corresponding relationship between the logical and physical order of the records and determine the storage address to improve the data access speed. Among the various connection methods between servers and storage, DAS was once considered an inefficient structure and inconvenient for data protection.

Direct-attached storage cannot be shared, so it often happens that a certain server has insufficient storage space, while other servers have a large amount of idle storage space that cannot be used.

9. What is the concept of blockchain? Read it in three minutes!

On October 25, 2019, Xinwen Broadcast sent a very important signal: the country must vigorously develop blockchain. After that, blockchain has become an Internet celebrity, and the figure of "blockchain" is floating in the streets and alleys. In fact, many technology companies have already deployed blockchain technology.

Although blockchain is very popular, many people do not know much about blockchain.

What is blockchain?

Let’s first take a look at how Du Niang explained it. Network display: Blockchain is a new application model of computer technologies such as distributed data storage, point-to-point transmission, consensus mechanism, and encryption algorithms.

Why is blockchain called blockchain?

The blockchain is linked by blocks one by one, and the blocks are storage units one by one, which record the communication information of each block node. The blocks are much like the records of the database. Writing data every time creates a block. With the expansion of information exchange, one block continues with another, and the result is called a blockchain.

What are the characteristics of blockchain?

Blockchain mainly has the following characteristics:

1. Decentralization: In the blockchain system, every node has equal rights. and obligations, there is no central control here. Decentralization has well established trust relationships with each other. Although there is no central management organization, people can collaborate with each other and trust each other. This mainly applies blockchain distributed ledger technology.

2. Openness: Blockchain data is open to everyone. Except for some encrypted information that is not open, everyone can check the data here.

3. Independence: 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: Blockchain has a certain degree of security and cannot be tampered with. Because everyone in the blockchain system has the same ledger, if someone wants to tamper with it, it is possible to forge a non-existent record only if they control more than 51% of the accounting nodes. Of course, this is basically impossible. This is mainly due to the core technology of the blockchain: the consensus mechanism. The consensus mechanism has the characteristics of "the minority obeys the majority" and "everyone is equal".

5. Anonymity: Many people think that if the blockchain is so open and transparent, will we lose privacy? In fact, no, although the transaction information in the blockchain is open and transparent, the identity information of the account is encrypted and can only be accessed with authorization.

Now let me tell you a story to help you better understand the blockchain.

There are three people in the family, mom, dad, older brother and younger brother. Last year, my father was in charge of the family's account books. He was responsible for all the family's income and expenses alone.

However, on the day of Double Eleven, my mother, who has always been frugal, wanted to buy herself a beautiful piece of clothing on a certain online store. When she checked the account book, she found something was wrong. It stands to reason that except for some money deposited in banks and financial management, the whereabouts of the daily consumption money at home are all in this account book, but no matter how you look at it, it is wrong. Some consumption is clearly not recorded, but is recorded.

Later, my father took the initiative to confess that he couldn’t help but buy a pack of cigarettes.

Later, my mother changed her strategy and the whole family kept accounts. Everyone recorded their monthly consumption expenditure in their own account books. Whenever there was a transaction or consumption at home, my mother would shout, "Book it," and everyone would record the transaction in their own books. This is the decentralized accounting model, where everyone is the center and everyone has a ledger.

The previous accounting model for dad was centralized accounting. If dad wanted to do something alone, it would be difficult for anyone to see it. The decentralized accounting model has solved the problem of centralization very well. The disadvantage of bookkeeping is that it is very difficult for dad to tamper with the books.

For example, if my father wants to take some money from the ledger and secretly buy cigarettes, the amount of money is limited, and if he wants to take the money, he has to change the ledger, but he only tampered with his own ledger. No, he had to change the accounts of three people including himself. And this is undoubtedly more difficult than reaching the sky.

So, many times my father had the idea of ​​smoking, but he had no choice but to give up the idea due to the current situation.

Are blockchain and Bitcoin the same thing?

In fact, blockchain and Bitcoin are not the same thing. It is just the underlying technology of Bitcoin. Bitcoin is the first digital currency applied by blockchain.

In 2008, Satoshi Nakamoto first proposed the concept of blockchain. In the following years, it became a core component of the electronic currency Bitcoin, serving as a public account book for all transactions. Blockchain was first applied to Bitcoin.

The origin of blockchain is to solve the problem of trust, and one of the most successful applications of blockchain is digital currency. Bitcoin is arguably the most successful application of blockchain so far.

What are the applications of blockchain?

The application of blockchain is actually very wide. In addition to digital currency, the future applications of Bitcoin are still very extensive. Blockchain technology has been widely used in different industries. Such as product traceability, copyright protection and transactions, payment and settlement, Internet of Things, digital marketing, medical care, etc., promoting different industries to quickly enter the "blockchain+" era.

1. Payment and clearing: Blockchain can abandon the role of transit banks, realize point-to-point payment, reduce transit fees, and accelerate fund utilization.

2. Product traceability: For example, if we buy a piece of clothing on a certain store, we can see the past and present life of this piece of clothing.

3. Securities trading: Traditional securities trading requires the coordination of four major institutions, which is inefficient and costly. Blockchain technology can independently complete one-stop services.

4. Supply chain: Introducing blockchain technology into the supply chain system, synchronizing information within the system can control all links, better complete division of labor and collaboration, and facilitate subsequent accountability.

5. Intellectual property rights: With copyright on the chain, our photographic works, musical works, literary works, etc. will become our information, and the ownership of the information will be confirmed and become our property.

10. What is blockchain

Blockchain is a term in the field of information technology. Blockchain is an uninterrupted digital ledger of economic transactions that can be programmed to record not just financial transactions, but almost anything of value. Simply put, it is a decentralized, distributed database of immutable records that is managed by a cluster of computers but does not belong to any single entity. Blockchain is stored as a database or flat file.