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㈠ The Tongxin Huzhu website introduces the application of blockchain technology, what is blockchain

What is blockchain
Blockchain is a A decentralized, node-participated distributed ledger system. The data stored on it cannot be forged or tampered with, and is open and transparent. The information recorded and owned by each account at any point in history can be found on the blockchain. value. The characteristics of the blockchain protocol provide the necessary foundation for the operation of smart contracts. The contract can be automatically executed and trusted according to the established conditions in Bohanzhong without the need for review by any centralized organization.
Blockchain composition
Blockchain is composed of a series of data blocks generated using cryptography methods. Each block contains the hash value of the previous block, starting from Chuangjishan District Blocks begin to be linked to the current block, forming a chain of blocks. Each block is guaranteed to be generated after the previous block in chronological order, otherwise the hash value of the previous block is unknown. The generation of each block is supervised by the entire network. Each node has a complete copy of the data, forming a huge blockchain network between nodes.
The Tongxin Mutual Aid Platform that applies blockchain technology can solve the following points:

1. Openness and transparency
Openness and transparency, it is difficult to record all the information recorded on the blockchain It cannot be tampered with, cannot be hidden, and can be viewed by users at any time.
2. Democratic decision-making
Bottom-up decision-making, the blockchain proposes a variety of different consensus mechanisms to help users effectively form bottom-up decisions and jointly participate in major decisions.
3. Accurate execution of rules
Accurate execution of rules. The smart contract technology defined on the blockchain converts all rules into public and clear codes, which can be executed accurately. Once any determination is made, Humans cannot interfere.
4. Never downtime
Never downtime is boring. The blockchain based on the public chain is not affected by any institution or individual. As long as the incentive mechanism is effective and the Internet exists, the blockchain will be exist.
In short, network mutual aid applications developed based on the blockchain platform can maximize the absolute security of funds, protocols, and information, and improve risk control capabilities.

㈡ Tutorials for getting started with blockchain

However, there are very few simple and easy-to-understand introductory articles. What exactly blockchain is and what makes it special is rarely explained.
Next, I will try to write a best-understood blockchain tutorial. After all, it is not difficult. The core concept is very simple and can be explained clearly in a few sentences. I hope that after reading this article, you will not only understand the blockchain, but also understand what mining is, why mining is getting more and more difficult, and other issues.
It should be noted that I am not an expert in this area. Although I have been paying attention to it for a long time, my detailed understanding of blockchain started at the beginning of this year. You are welcome to correct any errors or inaccuracies in the article.
1. The essence of blockchain
What is blockchain? In a word, it is aSpecial distributed database.
First of all, the main function of blockchain is to store information. Any information that needs to be saved can be written to the blockchain and read from it, so it is a database.
Secondly, anyone can set up a server, join the blockchain network, and become a node. In the world of blockchain, there is no central node. Every node is equal and stores the entire database. You can write/read data to any node, because all nodes will eventually be synchronized to ensure that the blockchain is consistent.
2. The biggest features of blockchain
Distributed databases are not a new invention, and there have been such products on the market for a long time. However, blockchain has a revolutionary feature.
Blockchain has no administrator, it is completely centerless. Other databases have administrators, but blockchain does not. If one wanted to add auditing to the blockchain, it would not be possible because it is designed to prevent the emergence of a central authority.
It is precisely because it is unmanageable that blockchain can be uncontrollable. Otherwise, once big companies and large groups control the management, they will control the entire platform, and other users will have to take orders from them.
However, without an administrator, everyone can write data into it. How can we ensure that the data is trustworthy? What if it is modified by a bad person? Please read on, this is the wonderful thing about blockchain place.
3. Block
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.
Head: records the characteristic values ​​of the current block
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
...
Here, you need to understand what a hash is , which is necessary to understand blockchain.
The so-called hashing 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), which is 256 bits when converted to binary, 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 approximated as 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.
4. The non-modifiable nature of Hash
Blocks and hashes have a one-to-one correspondence.Hashes are calculated based on the block header (Head). 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 contains the block header and not the block body. In other words, the hash is uniquely determined by the block header.
As mentioned before, 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 point has great significance for 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.
Each block is connected to the previous block, which is where the name blockchain comes from.
5. Mining
Since synchronization between nodes must be ensured, the adding speed of new blocks cannot be too fast. Just imagine, you have just synchronized a block and are preparing to generate the next block based on it, but at this time, another node generates a new block, and you have to give up half of the calculations and synchronize again. Because each block can only be followed by one block, you can only generate the next block after the latest block. So, you have no choice but to sync as soon as you hear the signal.
So, the inventor of the blockchain, Satoshi Nakamoto (this is a pseudonym, and his true identity is still unknown) deliberately made it difficult to add new blocks. His design is that on average, the entire network can generate a new block every 10 minutes, which is only six per hour.
This output speed is not achieved through commands, but by deliberately setting up massive calculations. In other words, only through an extremely large amount of calculations can the effective hash of the current block be obtained and the new block added to the blockchain. Because the amount of calculation is too large, it cannot be done quickly.
This process is called mining, because the difficulty of calculating a valid hash is like finding a grain of sand that meets the conditions among the sand in the world. The machine that calculates hashes is called a mining machine, and the person who operates the mining machine is called a miner.
6. Difficulty coefficient
After reading this, you may have a question. People say that mining is difficult, but isn’t mining just about using a computer to calculate a hash?This is exactly the strength of computers. Why does it become so difficult and so long that it can’t be calculated?
It turns out that not just any hash can be used. Only hashes that meet the conditions will be accepted by the blockchain. This condition is particularly harsh, causing most hashes to fail to meet the requirements and must be recalculated.
It turns out that the block header contains a difficulty coefficient (difficulty), which determines the difficulty of calculating the hash. For example, the difficulty coefficient of the 100,000th block is 14484.16236122.
The blockchain protocol stipulates that the target value (target) can be obtained by dividing the difficulty coefficient by a constant. Obviously, the greater the difficulty coefficient, the smaller the target value.
The validity of the hash is closely related to the target value. Only hashes smaller than the target value are valid, otherwise the hash is invalid and must be recalculated. Since the target value is very small, the chance that the hash is smaller than this value is extremely slim, and it may be calculated 1 billion times before it is considered a hit. This is the fundamental reason why mining is so slow.
As mentioned earlier, the hash of the current block is uniquely determined by the block header. If the hash of the same block needs to be calculated repeatedly, it means that the block header must keep changing, otherwise it is impossible to calculate different hashes. All feature values ​​in the block header are fixed. In order to make the block header change, Satoshi Nakamoto deliberately added a random item called Nonce.
Nonce is a random value. The role of the miner is actually to guess the value of Nonce so that the hash of the block header can be smaller than the target value so that it can be written to the blockchain. Nonce is very difficult to guess. At present, we can only use trial and error one by one through exhaustive methods. According to the protocol, Nonce is a 32-bit binary value, which can reach a maximum of 2.147 billion. The Nonce value of the 100,000th block is 274148111. It can be understood that the miner started from 0 and calculated 274 million times before obtaining a valid Nonce value so that the calculated hash can meet the conditions.
If you are lucky, you may find Nonce in a while. If you are unlucky, you may have calculated it 2.147 billion times without finding the Nonce, that is, it is impossible to calculate a hash that meets the conditions for the current block body. At this time, the protocol allows miners to change the block body and start a new calculation.
7. Dynamic adjustment of difficulty coefficient
As mentioned in the previous section, mining is random, and there is no guarantee that a block will be produced in exactly ten minutes. Sometimes it can be calculated in one minute, and sometimes it may take several hours. No result. Overall, with the improvement of hardware equipment and the increase in the number of mining machines, the computing speed will definitely become faster and faster.
In order to keep the output rate constant at ten minutes, Satoshi Nakamoto also designed a dynamic adjustment mechanism for the difficulty coefficient. He stipulated that the difficulty factor should be adjusted every two weeks (2016 blocks). If the average block generation speed during these two weeks is 9 minutes, it means that it is 10% faster than the legal speed, so the subsequent difficulty factor must be increased by 10%;If the average generation speed is 11 minutes, it means that it is 10% slower than the legal speed, so the subsequent difficulty factor must be lowered by 10%.
The difficulty coefficient is adjusted higher and higher (the target value is getting smaller and smaller), which makes mining more and more difficult.
8. Forks of the blockchain
Even if the blockchain is reliable, there is still an unresolved problem: if two people write data to the blockchain at the same time, that is to say, two people write data to the blockchain at the same time. Blocks join because they are connected to the previous block, forming a fork. Which block should be adopted at this time?
The current rule is that new nodes always adopt the longest blockchain. If there is a fork in the blockchain, it will look at which branch is behind the fork to reach 6 new blocks first (called six confirmations). Based on a block calculation of 10 minutes, it can be confirmed in one hour.
Since the generation speed of new blocks is determined by computing power, this rule means that the branch with the most computing power is the authentic blockchain.
9. Summary
Blockchain, as an unmanaged distributed database, has been running for 8 years since 2009 without major problems. This proves it works.
However, in order to ensure the reliability of data, blockchain also has its own price. The first is efficiency. You have to wait at least ten minutes to write data to the blockchain. All nodes synchronize the data, which requires more time. The second is energy consumption. The generation of blocks requires miners to perform countless meaningless calculations. This is Very energy consuming.
Therefore, the applicable scenarios of blockchain are actually very limited.
There is no management authority that all members trust
The written data does not require real-time use
The benefits of mining can make up for its own costs
If the above conditions cannot be met, then the traditional database is Better solution.
Currently, the largest application scenario (and possibly the only application scenario) of blockchain is the cryptocurrency represented by Bitcoin.

iii Components of Blockchain

The components of Blockchain are as follows:

Openness: Area The system data of the blockchain 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.

The 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 that your various ID card information and phone numbers will not be resold.

㈣ Are there 7 core technologies for blockchain operation that you should know?

How many of the 7 core technologies for blockchain operation do you know?
1 .Blockchain link
As the name suggests, blockchain is a chain composed of blocks. Each block is divided into two parts: block header and block body (including transaction data). The block header includes the hash (PrevHash) value (also called hash value) of the previous block used to implement block linking and the random number (nonce) used to calculate the mining difficulty. The hash value of the previous block is actually the hash value of the header of the previous block, and the rules for calculating random numbers determine which miner can obtain the power to record the block.
2. Consensus Mechanism
Blockchain was born with Bitcoin and is the basic technical architecture of Bitcoin. Blockchain can be understood as a decentralized accounting system based on the Internet. A decentralized digital currency system like Bitcoin requires blockchain to ensure the consistency of accounting by each honest node without a central node. Therefore, the core of blockchain technology is a consensus mechanism that reaches a consensus on the legality of transactions among individuals who have no basis for trust in each other without central control.
There are currently four main categories of blockchain consensus mechanisms: PoW, PoS, DPoS, and distributed consensus algorithms.
3. Unlocking scripts
Scripts are an important technology for automatic verification and automatic execution of contracts on the blockchain. Each output of each transaction does not strictly point to an address, but to a script. A script is like a set of rules that govern how the recipient can spend the assets locked on this output.
The legality verification of transactions also relies on scripts. Currently it relies on two types of scripts: locking scripts and unlocking scripts. The locking script is a condition added to the output transaction, implemented through a script language, and is located at the output of the transaction. The unlocking script corresponds to the locking script. Only if the conditions required by the locking script are met, the corresponding assets on this script can be spent, which is located at the input of the transaction. Many flexible items can be expressed through scripting language. The interpretation script is similar to a "virtual machine" in our programming field, which is distributed and runs on every node in the blockchain network.
4. Transaction Rules
Blockchain transactions are the basic units that constitute blocks, and are also the actual effective content that the blockchain is responsible for recording. A blockchain transaction can be a transfer or other transactions such as the deployment of smart contracts.
In the case of Bitcoin, a transaction refers to a payment transfer. The trading rules are as follows:
1) The input and output of the transaction cannot be empty.
2) For each input of the transaction, if its corresponding UTXO output can be found in the current transaction pool, the transaction will be rejected. Because the current transaction pool is a transaction that has not been recorded in the blockchain, and each input of the transaction should come from a confirmed UTXO. if at that timeIf found in the previous trading pool, it is a double-spend transaction.
3) For each input in the transaction, its corresponding output must be UTXO.
4) Each input unlocking script must work with the corresponding output locking script to verify the compliance of the transaction.
5. Transaction Priority
The priority of blockchain transactions is determined by the blockchain protocol rules. For Bitcoin, the priority of a transaction being included in a block is determined by the time it takes for the transaction to be broadcast to the network and the size of the transaction. As the time it takes for a transaction to be broadcast to the network increases and the chain age of the transaction increases, the priority of the transaction is increased and will eventually be included in the block. For Ethereum, the priority of a transaction is also related to the transaction fee that the publisher of the transaction is willing to pay. The higher the transaction fee that the publisher is willing to pay, the higher the priority of the transaction being included in the block.
6.Merkle proof
The original application of Merkle proof is the Bitcoin system (Bitcoin), which was described and created by Satoshi Nakamoto in 2009. The Bitcoin blockchain uses Merkle proofs in order to store transactions in every block. This makes the transaction unable to be tampered with and makes it easy to verify whether the transaction is included in a specific block.
7.RLP
RLP (Recursive Length Prefix, recursive length prefix encoding) is a main encoding method for object serialization in Ethereum. Its purpose is to encode any nested sequence of binary virtual data. Lu Ji

㈤ Blockchain Information Service Management Regulations

Article 1 is to regulate blockchain information service activities, safeguard national security and social public interests, and protect citizens, The legitimate rights and interests of legal persons and other organizations, to promote the healthy development of blockchain technology and related services, in accordance with the "Cybersecurity Law of the People's Republic of China", "Measures for the Administration of Internet Information Services" and the "State Council's Authorization of the National Internet Information Office to be responsible for the management of Internet information content" "Notice on Work" and formulate these regulations. Article 2 Those engaged in blockchain information services within the territory of the People's Republic of China must comply with these regulations. If laws and administrative regulations provide otherwise, such provisions shall prevail. The term “blockchain information services” as mentioned in these regulations refers to the provision of information services to the public through Internet websites, applications, etc. based on blockchain technology or systems. The term "blockchain information service provider" as mentioned in these regulations refers to the entities or nodes that provide blockchain information services to the public, as well as the institutions or organizations that provide technical support to the entities of blockchain information services; the term "blockchain" as mentioned in these regulations refers to Chain information service users refer to organizations or individuals who use blockchain information services. Article 3 The Cyberspace Administration of China shall be responsible for the supervision, management and law enforcement of blockchain information services nationwide in accordance with its duties. The Internet Information Offices of provinces, autonomous regions, and municipalities directly under the Central Government are responsible for the Bank’sSupervision, management and law enforcement of blockchain information services within the administrative region. Article 4 encourages blockchain industry organizations to strengthen industry self-discipline, establish and improve industry self-discipline systems and industry standards, guide blockchain information service providers to establish and improve service specifications, promote the construction of industry credit evaluation systems, and supervise blockchain information service providers Provide services in accordance with the law, accept social supervision, improve the professional quality of blockchain information service practitioners, and promote the healthy and orderly development of the industry. Article 5 Blockchain information service providers shall implement information content security management responsibilities and establish and improve management systems for user registration, information review, emergency response, and security protection. Article 6 Blockchain information service providers shall have technical conditions suitable for their services. For information content prohibited by laws and administrative regulations, they shall have immediate and emergency response capabilities and technical solutions for the release, recording, storage, and dissemination of information content prohibited by laws and administrative regulations. It should comply with relevant national standards and specifications. Article 7 Blockchain information service providers should formulate and disclose management rules and platform conventions, sign service agreements with blockchain information service users, clarify the rights and obligations of both parties, and require them to promise to abide by legal regulations and platform conventions. Article 8 Blockchain information service providers shall, in accordance with the provisions of the "Cybersecurity Law of the People's Republic of China", collect the real identity information of blockchain information service users based on organizational codes, ID number or mobile phone number, etc. Certification. If users do not authenticate their real identity information, blockchain information service providers shall not provide relevant services for them. Article 9 If a blockchain information service provider develops and launches new products, new applications, or new functions, it shall report to the national and provincial, autonomous region, or municipality Internet Information Office for security assessment in accordance with relevant regulations. Article 10 Blockchain information service providers and users shall not use block chain information services to engage in activities that endanger national security, disrupt social order, infringe upon the legitimate rights and interests of others, or other activities prohibited by laws and administrative regulations, and shall not use block chain information services to produce , copy, publish, and disseminate information content prohibited by laws and administrative regulations. Article 11 Blockchain information service providers shall fill in the name, service category, service form, and application of the service provider through the Blockchain Information Service Registration Management System of the Cyberspace Administration of China within ten working days from the date of provision of services. Domain, server address and other information, and complete the filing procedures. If a blockchain information service provider changes its service items, platform URL, etc., it shall go through the change procedures within five working days from the date of change. If a blockchain information service provider terminates its services, it shall go through the cancellation procedures thirty working days before terminating its services and make appropriate arrangements. Article 12 After receiving the filing materials submitted by the filing party, the national and provincial, autonomous region, and municipality Internet Information Offices shall, if the materials are complete, be filed within twenty working days, issue a filing number, and pass the filing through the State Internet Information Office District The blockchain information service filing management system publishes filing information to the public; if the materials are incomplete, the filing will not be granted, and the filing person will be notified within twenty working days and the reasons will be explained. Article 13 Complete preparationThe registered blockchain information service provider shall indicate its registration number in a conspicuous position on the Internet websites, applications, etc. that provide external services. Article 14 The Internet Information Office of the state and provinces, autonomous regions, and municipalities directly under the Central Government shall conduct regular inspections of blockchain information service registration information. Blockchain information service providers shall log in to the blockchain information service registration management system within the specified time and provide relevant information. Article 15 If the blockchain information services provided by a blockchain information service provider have potential information security risks, they must make rectifications and comply with laws, administrative regulations and other relevant provisions and relevant national standards before they can continue to provide information services. Article 16 Blockchain information service providers shall take warning, function restriction, account closure and other disposal measures against blockchain information service users who violate laws, administrative regulations and service agreements in accordance with the law and contract, and deal with illegal information content Take corresponding measures in a timely manner to prevent the spread of information, save relevant records, and report to the relevant competent authorities. Article 17 Blockchain information service providers shall record information such as content and logs released by blockchain information service users, record backups shall be kept for no less than six months, and shall be provided when relevant law enforcement authorities inquire according to law. Article 18 Blockchain information service providers shall cooperate with the supervision and inspection implemented by the cybersecurity and informatization department in accordance with the law, and provide necessary technical support and assistance. Blockchain information service providers should accept social supervision, set up convenient complaint and reporting portals, and handle public complaints and reports in a timely manner. Article 19 Blockchain information service providers violate Article 5, Article 6, Article 7, Article 9, Article 11, Paragraph 2, Article 13, Article 15, Article 10 of these Regulations As stipulated in Articles 7 and 18, the national and provincial, autonomous region, and municipal Internet information offices shall give a warning in accordance with their duties and order them to make corrections within a time limit. The relevant business shall be suspended before making corrections; those who refuse to make corrections or the circumstances are serious shall be fined 5,000 yuan. A fine of not less than 30,000 yuan but not more than 30,000 yuan shall be imposed; if a crime is constituted, criminal liability shall be pursued in accordance with the law. Article 20 If a blockchain information service provider violates the provisions of Articles 8 and 16 of these Regulations, the Internet Information Office of the country and provinces, autonomous regions, and municipalities directly under the Central Government shall, in accordance with their duties and in accordance with the provisions of the Cybersecurity Law of the People's Republic of China, be processed. Article 21 If a blockchain information service provider violates the provisions of Article 10 of these Provisions by producing, copying, publishing, or disseminating information content prohibited by laws and administrative regulations, the Internet Information Office of the country, provinces, autonomous regions, and municipalities directly under the Central Government shall, on the basis of Responsibilities include giving a warning and ordering correction within a time limit, and relevant business should be suspended before correction; if the violation is refused or the circumstances are serious, a fine of not less than RMB 20,000 but not more than RMB 30,000 will be imposed; if a crime is constituted, criminal liability shall be pursued in accordance with the law. If users of blockchain information services violate the provisions of Article 10 of these Provisions and produce, copy, publish, or disseminate information content prohibited by laws and administrative regulations, the national and provincial, autonomous region, and municipality Internet Information Offices shall, in accordance with relevant laws and administrative regulations, regulations will be dealt with. Article 22 Blockchain information service providers violate the provisions of Article 11, paragraph 1, of these regulations and fail to comply with these regulations.Anyone who performs filing procedures or fills in false filing information will be ordered by the national and provincial, autonomous region, or municipality Internet Information Offices to make corrections within a time limit based on their duties; if they refuse to make corrections or the circumstances are serious, they will be given a warning and fined not less than RMB 10,000 but not more than RMB 30,000. Article 23 Those who engage in blockchain information services before the promulgation of these regulations shall complete relevant procedures in accordance with these regulations within twenty working days from the date when these regulations come into effect. Article 24 These regulations will come into effect on February 15, 2019.

㈥ Give an example of what is blockchain

Question 1: What is blockchain technology? What exactly is blockchain? What is blockchain? 1. Data blockchain is an important concept in the Bitcoin financial system. It records transaction record data on the entire Bitcoin network, and these data are shared by all Bitcoin nodes. Through the data block, we can query each transaction record. A look at the history of Bitcoin transactions. 2. Example: There are three persons A, B, and C. All funds of A and B are kept by C. And every financial transaction must be recorded by C. Now assume that A and B each have 1 million in custody of C. Then: A spends 80,000 yuan to B, then C's account book record will subtract 80,000 yuan from A's name, and add 80,000 yuan to B's name. If B transfers 50,000 yuan to A, C will add 50,000 yuan to A's name and subtract 50,000 yuan to B's name in the account book. A spends 50,000 yuan to B, then C's account book record will subtract 50,000 yuan from A's name, and add 50,000 yuan to B's name. 3. The role of the data blockchain is similar to that of C’s account record book. It records the user’s ownership of Bitcoin and the records of all users’ Bitcoin transactions. It’s just that this “account record book” is recorded by the mining software of every Bitcoin miner on the network. If a Bitcoin transaction is confirmed by the data blockchain, the relevant information will be recorded in the data blockchain. Bitcoin’s “account record book” is called the data blockchain. All data blockchains on the network form Bitcoin’s distributed network database system. 4. The essence of data blockchain technology is a decentralized and distributed structure of data storage, transmission and certification methods. It uses data blocks to replace the current Internet's dependence on central servers, so that all data changes or transaction items are recorded. On a cloud system, the self-certification of data during data transmission is theoretically realized. In a far-reaching sense, this transcends the traditional and conventional information verification paradigm that relies on a center and reduces the cost of establishing global "credit." This point-to-point verification will produce a "basic protocol", which is a new form of distributed artificial intelligence and will establish a new interface and shared interface between human brain intelligence and machine intelligence.

Question 2: What is the transaction process of the blockchain? Best to give an example 20 points 1. Definition
Blockchain is like an open network ledger. It originated from Bitcoin and is the underlying technology of Bitcoin. In Bitcoin transactions, all information recorded in the transactionInformation will be packaged into a "Block" for storage. With the expansion of information exchange, blocks are linked to each other, forming a blockchain.
2. Characteristics
Digital currency represented by Bitcoin is a peer-to-peer electronic cash system. Among them, each transaction will be broadcast to all participants in the network, and will be recorded in the ledger after multiple confirmations. This ledger is the "blockchain". Each participant will have his own ledger. In this way, when false information occurs, it can be broken through mutual verification, thereby ensuring network security.
In the blockchain, every node is equal, and there is no centralized management organization. This "decentralization" feature makes the blockchain unnecessary to rely on third parties, and its operation does not require any human effort. intervention, capable of independent self-validation. In addition, the blockchain network is open to the world, and anyone can query data through the public port, so the entire system is highly transparent.
3. Application
In short, the blockchain is a trusted database and a reliable "ledger". In the future, it will be used in cross-border payments, securities, loans, voting, etc. For example, in cross-border payments, with the security provided by blockchain, money can be sent to the world anytime and anywhere, thus eliminating many intermediate links and high handling fees.

Question 3: What is blockchain? What does it mean in layman’s terms? What is China’s attitude towards blockchain? What can blockchain do? Blockchain, a great technology that accompanied the birth of Bitcoin, is currently being used in the financial field to significantly reduce transaction costs and improve efficiency, which is enough to excite Wall Street. However, this is just the tip of the iceberg. Its potential applications are very broad and will subvert every aspect of our lives in the future.
Blockchain is an important concept of Bitcoin. It is essentially a decentralized database and serves as the underlying technology of Bitcoin. One of the most basic characteristics of Bitcoin is decentralization. In recent months, financial giants have gradually begun to pay attention to Bitcoin's technology and used it in non-monetary fields, such as stock trading, election voting, etc. (1) Art Industry
Artists can use blockchain technology to declare ownership and issue numberable, 100% edition works in digital form for any type of artwork. It even includes a marketplace where artists can buy and sell through their website without the need for any intermediary services.
(2), Real estate industry
Use blockchain technology to solve various problems faced by everyone involved in real estate, including the naming process, land registration, agency intermediaries, etc.
(3), Insurance Industry
The financial industry has always been the most sensitive to advanced technology. Traditional banking and securities industry giantsIn 2014, they have been involved in the booming blockchain venture capital investment. Within two years, the total global investment reached US$1 billion.
(4) P2P wallet
Personal assets can be traded through this P2P wallet in the future without going through any central institution, such as Bitcoin.
Most blockchains are in their infancy, mainly overseas. There are very few good domestic blockchain projects, so it is not recommended for any non-professionals to invest in blockchain projects. If you are very interested in blockchain technology and have a technical or financial background, it is recommended that you consider starting a business in this area. In terms of the blockchain protocol system, the lowest layer is the underlying technology of the blockchain, including the technical protocols of the blockchain, as well as some platform routing and basic algorithms; in the middle layer, some application interfaces and some credentials must be solved Issuance and verification, including some industry platform services, big data analysis, etc. This is a very rough classification, and there should be more detailed classifications; the top ones are some applications of blockchain, including finance Some applications and some applications in other aspects, the Internet of Things and so on.
Introduction to Bubi Blockchain
Bubi Blockchain has been focusing on the research and development and innovation of blockchain technology and products since its establishment. It has a number of core technologies and has achieved substantial results in many aspects. Radical innovation has resulted in a number of core technological achievements, such as: mathematically provable distributed consensus technology, fast large-scale ledger access technology, multi-chain general ledger technology that supports business expansion, and interconnection technology between heterogeneous blockchains. wait. On April 25, "Gege Points" introduced the concept of blockchain into the points system, jointly opened it up with multiple parties, issued and redeemed points, and promoted the circulation of points. Each cooperative institution can jointly participate in transaction verification, ledger storage, and real-time settlement; the third-party payment platform of the enterprise points issuer makes the entry and exit of points more flexible. Bubi has developed its own basic blockchain service platform, which has been applied in equity, supply chain, points, credit and other fields. Bubi has been committed to building an open value circulation network with decentralized trust as the core, allowing digital assets to flow freely.
A simple understanding of blockchain is a technology at the bottom of Bitcoin, which is also a peer-to-peer electronic cash system that can realize peer-to-peer value delivery. We should distinguish between Bitcoin, Bitcoin blockchain, blockchain and blockchain. Blockchain technology and other concepts. In countries with relatively developed finance in the past, finance and blockchain technology have a long history, and the legislation of digital currencies and blockchain networks is also very important. With the advent of the financial era, large financial institutions are studying blockchain technology. They have their own teams and conceptual technologies. Slowly, banks in various regions are also participating in digital currency discussions. The application and support of this technology are not only that. The influence of blockchain on enterprises is also huge. For larger domestic enterprises, Bubi Blockchain is also used in various equity, supply chain, points and other fields. Major domestic financial institutions and enterprises have taken a fancy to the new industry. value, one after anotherWith its own blockchain platform, blockchain has instantly become a new innovative industry in China. In terms of overseas internationalization, the United States has already obtained 15 blockchain patents at the end of last year compared to China. Blockchain financial applications are entering a new stage in an all-round way. Various applications will become more and more in-depth, and related changes will also become more and more profound. It is attracting more and more attention and will form a huge new trend... >>

Question 4: What is blockchain technology? What is blockchain? How to explain the concept of blockchain? People in each industry have different understandings, and relevant explanations are gradually emerging due to more and more real-life applications. With the popularization of this blockchain technology, the related results are getting bigger and bigger. If we want to understand this technology, we must have an in-depth understanding of reality.
In the past six months, the concept of blockchain has gradually become popular in China, and a blockchain whirlwind has taken off in the financial circle. Blockchain has attracted the attention and favor of more and more people in the industry due to its unique technical advantages. Blockchain technology, which is decentralized (or multi-centered), highly transparent, cannot be tampered with, and has no single point of failure, is entering the field of vision of financial institutions and enterprises. It has at least been used in digital currency, payment exchange, registration and settlement, Digital assets, traceability and anti-counterfeiting, supply chain, Internet of Things and many other fields have moved from theoretical discussions to practical applications.
"Blockchain" was first introduced with "Bitcoin" released in early 2009. Blockchain has become the basic protocol and technical application for the launch, recording, and circulation of Bitcoin. Although Bitcoin has been controversial since its inception and cannot even be regarded as a "currency" by governments and monetary authorities, the blockchain technology used in Bitcoin has been recognized by governments, including governments and monetary authorities. extensive attention.
Why has blockchain become a rapidly heating up hot technology and topic?
The most important of these may be that the launch of Bitcoin based on blockchain technology has opened up a new relationship with traditional society ( The exploration and attempt of new technologies and rule systems such as Internet user identity verification, wealth confirmation, transaction records, notarization and verification, which have little connection with offline) and are completely applied to the online world (online), provide people with the opportunity to adapt to the Internet society. Development provides alternative paths and unlimited imagination.
Judging from its application in Bitcoin, blockchain is a set of new network blocks (BLOCK, also called communities) formed by combining encryption technology with the Internet. Bitcoin configuration, netizen identity verification, and Bitcoin (value) confirmation formed by mining, Bitcoin transaction records, and extended encryption of Bitcoin cross-block flow (value transfer) (added block and transaction time identification, etc. Internet protocol rules and accounting (Ledger) system including block chain, full encryption, mutual authentication, etc., including factor) registration and verification. Precisely because Bitcoin is not a substitute for offline legal currency, but a non-legal currency.It is a new, decentralized online currency (virtual currency) issued and managed by the bureau, mainly imitating the gold model, and completely protected and supported by Internet basic protocols and strict encryption technology. This has also formed a set of different, It is not subject to the new currency rules and systems of real social laws, and can be bought, sold or exchanged with legal currency. It has been more than 8 years since Bitcoin was launched. There has been no record of funds or user information being stolen. Its security has been verified, and its efficiency and cost of fund settlement also have obvious advantages. This has made people's confidence in the blockchain technology used in Bitcoin continue to increase, and people have become more and more aware that although blockchain is a technology and protocol pioneered and applied by Bitcoin, the blockchain Chain is not the same as Bitcoin, and its application is by no means limited to Bitcoin. The application of blockchain can be decentralized or centralized; it can be a public chain model or a private chain model. Therefore, after Bitcoin, blockchain technology is also constantly developing and innovating, and constantly exploring new application fields, especially in the financial field.
The reason why blockchain is valued highly by more and more people is because the development and widespread application of the Internet have caused more and more economic exchanges and transaction activities to be conducted online, and the online world (or online world) society) is rapidly expanding, enriching and active, and online transactions must solve the efficiency and security protection issues of the parties' identity verification, value verification, transaction records, inspection and verification, etc., and require strict intermediaries and agreements (rules or constitutions). In this regard, traditional thinking and customary practices are to follow the development trajectory of the transfer of offline transactions to online and push the common rules and practices of the real (offline) society to the online (network) society. However, in practice, it is increasingly It is difficult to adapt to the needs of online transactions.
For example, for the identity verification of the parties, the natural choice is to use the information on the identity documents protected by the laws of various countries as the basis, and then add account or transaction passwords, as well as facial recognition, iris, fingerprints and other biometrics to conduct online transactions. Verification, but this method first makes the citizen identity information in the cross-border interconnected online world subject to the administrative jurisdiction of real society... >>

Question 5: The so-called "district" What is "Blockchain"? Blockchain itself is a tool called decentralization and trustlessness. For example, when you graduate from university, the current practice is to have a certificate recognized and issued by an authoritative agency as your certificate. This setting is more troublesome, because this is a piece of paper, and paper can be forged, so there will be various gaps. The issuing authority is also a person, and there will be various gaps in the middle. As long as it is related to people, whoever There are various possibilities related to media. The blockchain provides a great opportunity. As soon as you graduate, you will have a record on the blockchain. No one can change this record. This thing exists objectively. You, as a physical existence, and then as a data existence, the blockchain was born. In this case, anyone who wants to check where you graduated can easily solve the problem. This is similar to the big data often involved in social networking (WeChat) and payment platforms (Alipay, Yibao).

Question 6: What is blockchain? Can you explain the principle of 10-point blockchain in plain language: decentralized distributed accounting system
Blockchain The core of the technology is that all currently participating nodes jointly maintain transactions and databases. It makes transactions based on cryptographic principles rather than trust, so that any two parties who reach an agreement can directly conduct payment transactions without the participation of a third party.
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Technically speaking, a block is a data structure that records transactions, reflecting the flow of funds for a transaction. The blocks of transactions that have been reached in the system are connected together to form a main chain, and all nodes participating in the calculation record the main chain or part of the main chain. A block contains the following three parts: transaction information, hash hash formed by the previous block, and random number. Transaction information is the task data carried by the block, specifically including the private keys of both parties to the transaction, the number of transactions, the digital signature of electronic currency, etc.; the hash formed by the previous block is used to connect the blocks to realize the past The order of transactions; random numbers are the core of transaction completion. All miner nodes compete to calculate the answer to the random number. The node that gets the answer the fastest generates a new block and broadcasts it to all nodes for update, thus completing a transaction.
1.1 What is Blockchain
Blockchain (BlockChain) refers to a technical solution that collectively maintains a reliable database through decentralization and trustlessness. This technical solution mainly allows any number of nodes participating in the system to associate and generate a series of data blocks (blocks) using cryptographic methods. Each data block contains all the information exchange data of the system within a certain period of time, and generates The data fingerprint is used to verify the validity of its information and chain to the next database block.
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In layman’s terms, blockchain technology refers to a way for all people to participate in accounting. Behind all systems there is a database, which is a big ledger. Then who will keep this ledger becomes very important. At present, it is whoever owns the system who keeps the accounts. Each bank’s account books are kept by each bank, and Alipay’s account books are kept by Alibaba. But now in the blockchain system, everyone in the system has the opportunity to participate in accounting. If there are new transaction data changes within a certain period of time, everyone in the system can do accounting. The system will judge the person who has the fastest and best accounting during this period, write the recorded content to the ledger, and Send the contents of the ledger during this period to all other people in the system for backup. In this way, everyone in the system has a complete ledger. Therefore, this data becomes very safe. usurpA modifier needs to modify more than half of the system node data at the same time to truly tamper with the data. Such tampering would be extremely costly, making it nearly impossible. For example, Bitcoin has been running for more than 7 years. Countless hackers around the world have tried to attack Bitcoin, but so far there have been no transaction errors. It can be considered that the Bitcoin blockchain has been proven to be a safe and reliable system.
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1.2 Why is there blockchain innovation?
Human beings need to communicate during their activities, and communication is based on information. In the past, information circulation was not convenient enough to satisfy market participants. There is a demand for information, so intermediaries and centers are born. This centralized system has problems such as high cost, low efficiency, value dispersion, "information islands" and insecure data storage. However, due to technical and environmental factors, this system continued to operate for many years until the emergence of the Internet. The starting point of the first generation of the Internet is the TCP/IP protocol, which is an open code that implements a unified format for peer-to-peer transmission of information by all nodes on the network, and brings the basic values ​​of freedom and equality required by a global unified market into programmed, protocol-based, and reliably Execution. The Internet eliminates low-value, high-cost intermediate chains and achieves low-cost and high-efficiency global information transmission in a decentralized manner.
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However, the first generation of the Internet did not solve the problem of information credibility. Activities that can be decentralized on the Internet must be activities that do not require credit endorsement, and activities that require credit guarantee must be activities involving centralized third-party intermediaries. Therefore, Internet technology that cannot establish global credit has encountered great obstacles in its progress - people cannot participate in any value exchange activities on the Internet in a decentralized manner. To realize value exchange, people still need third-party intermediaries based on credit (such as banks, clearing agencies, exchanges). The global centralized credit system still has problems such as high operating costs, low efficiency, and vulnerability to attacks and damage. For example, each country's legal currency has different credit values ​​and incompatible clearing systems, which adds a lot of cost to global trade.
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Therefore, what the second generation Internet must break through is: how to establish global credit in a decentralized manner? Let...>>

Question 7: Explain clearly what is blockchain in an easy-to-understand manner. The English name for blockchain is Blockchain. Block literally means block, block, and chain means chain, chain. Therefore, together they are translated into blockchain.
1. Use cryptography technology to encrypt and decrypt so that records cannot be tampered with. Common blockchain encryption methods include hash algorithm, RSA algorithm, elliptic curve algorithm, etc.;
2. The huge amount of calculation needs to be supported by a reasonable reward mechanism. Because every transaction must be recorded, Bitcoin’s blockchain has more than 60 gigabytes so far. Each new transaction requiresAll information related to the trading account must be confirmed before the transaction is confirmed to be valid. The huge amount of calculation requires a computer with powerful computing power to complete.
In order to encourage the participation of powerful computing power, Bitcoin provides two rewards: one is to issue a certain number of Bitcoins to these computers every day; instead, all transfer fees are awarded to these computers. (The technical term for these computers is "mining machines", and the people who hold the mining machines are called "miners".)
Biying China is working hard on the digitization of assets and has launched the digital currency crowdfunding platform Biying China.

Question 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. The so-called consensus mechanism is a mathematical algorithm that establishes trust and obtains rights and interests between different nodes in the blockchain system.
In May 2016, the Currency Blockchain Research Center published the first book in China that introduces blockchain in simple terms, "Blockchain: Defining a New Pattern of Future Finance and Economics." It introduces the impact of blockchain technology on future finance and economy

Question 9: What is blockchain? For the time being, this is a relatively high-end technology. It connects all nodes (which can be understood as servers) through p2p network technology. Complete data (blocks) are stored on each node. The addition and withdrawal of any node will not affect the normal operation of the chain. Data is embodied in the form of data blocks. Blocks are connected to each other and can be understood as a one-way linked list. The hash value of the nth block is generated based on the hash of the n-1th block, the transaction recorded in the current block, and the random number as parameters. In this way, if you want to modify the data of the historical block, you have to modify all the blocks from the modified block to the final block. The difficulty can be imagined.
The blockchain also introduces a consensus mechanism and an incentive mechanism. There is no way to describe it too comprehensively here. I hope everyone can discuss and learn together

Question 10: What is blockchain: This explanation of blockchain is more understandable. Blockchain (Blockchain) refers to the method of decentralization and trustlessness. A technical solution for collectively maintaining a reliable database.
In layman’s terms, blockchain technology refers to a way for all people to participate in accounting. There is a database behind all systems. You can think of the database as a big ledger. Then who will keep this ledger becomes very important. Currently, whoever owns the system keeps the accounts. Tencent keeps the accounts of WeChat, and Alibaba keeps the accounts of Taobao. But now in the blockchain system, everyone in the system has the opportunity to participate in accounting. If there are any data changes within a certain period of time, everyone in the system can do accounting. The system will judge the person who has the fastest and best accounting during this period, write his recorded content into the ledger, and record this period of timeThe contents of the internal ledger are sent to all other people in the system for backup. In this way, everyone in the system has a complete ledger. In this way, we call it blockchain technology.
Blockchain technology has become the darling of the financial community in China and has become a hot topic. Domestic Puyin Group has launched Puyin, a tea-based digital currency.

㈦ Consensus mechanism of blockchain

1. The goal of blockchain consensus mechanism

What is blockchain? Simply put, blockchain is a decentralized database, or it can be called a distributed ledger. Traditionally, all databases are centralized. For example, a bank's ledger is stored in the bank's central server. The disadvantage of a centralized database is that the security and accuracy of the data depend entirely on the database operator (i.e., the bank), because anyone who has access to the centralized database (such as bank employees or hackers) can destroy or modify the data in it.

Blockchain technology allows databases to be stored on thousands of computers around the world. Everyone’s ledger is synchronized through a peer-to-peer network, and anyone in the network can Once a user adds a transaction, the transaction information will be notified to other users through the network for verification and recorded in their respective ledgers. Blockchain gets its name because it is a data structure composed of blocks containing transaction information linked in an orderly manner from back to front.

Many people’s question about blockchain is that if each user has an independent ledger, does it mean that they can add to their own ledger? Arbitrary transaction information, and how can thousands of ledgers ensure the consistency of accounting? Solving the problem of accounting consistency is the goal of the blockchain consensus mechanism. The blockchain consensus mechanism aims to ensure that the data in all nodes in the distributed system are exactly the same and can reach agreement on a certain proposal (for example, a transaction record). However, due to the introduction of multiple nodes in a distributed system, various very complex situations will occur in the system; as the number of nodes increases, node failure or failure, network communication between nodes is interfered or even blocked, etc. In addition to common problems, solving various boundary conditions and unexpected situations in distributed systems also increases the difficulty of solving distributed consistency problems.

Blockchain can be divided into three types:

Public chain: full Anyone in the world can enter the system at any time to read data, send confirmed transactions, and compete for accounting in the blockchain. Public blockchains are generally considered "completely decentralized" because no one or institution can control or tamper with the reading and writing of data. Public chains generally encourage participants to compete for accounting through a token mechanism to ensure data integrity.safety.

Alliance chain: Alliance chain refers to a blockchain in which several institutions jointly participate in management. Each institution runs one or more nodes, and the data in it only allows different institutions within the system to read, write and send transactions, and jointly record transaction data. This type of blockchain is considered “partially decentralized.”

Private chain: refers to a blockchain whose write permission is controlled by an organization or institution. The qualifications of participating nodes will be strictly restricted. Since the participating nodes are limited and controllable, private chains can often have extremely fast transaction speeds, better privacy protection, lower transaction costs, and are not prone to malicious attacks. , and can meet the necessary requirements of the financial industry such as identity authentication. Compared with centralized databases, private chains can prevent single nodes within an organization from deliberately concealing or tampering with data. Even if an error occurs, the source can be quickly discovered, so many large financial institutions are currently more inclined to use private chain technology.

2. Classification of blockchain consensus mechanisms

The difficulty of solving distributed consistency problems has given rise to several consensus mechanisms, each of which has its own advantages and disadvantages, and is also suitable for different environment and issues. The consensus mechanisms that are common knowledge include:

l PoW (Proof of Work) workload proof mechanism

l PoS (Proof of Stake) ) Equity/Equity Proof Mechanism

l DPoS (Delegated Proof of Stake) Share Authorization Proof Mechanism

l PBFT (Practical Byzantine Fault Tolerance) Practical Byzantine Fault Tolerance Algorithm

l DBFT (Delegated Byzantine Fault Tolerance) Authorized Byzantine Fault Tolerance Algorithm

l SCP (Stellar Consensus Protocol) Stellar Consensus Protocol

l RPCA (Ripple Protocol Consensus Algorithm) Ripple Consensus Algorithm

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l Pool verification pool consensus mechanism

(1) PoW (Proof of Work) workload proof mechanism

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1. Basic introduction

In this mechanism, every node on the network is using the SHA256 hash functionA hash function calculates the hash sum of a changing block header. Consensus requires that the calculated value must be equal to or less than a given value. In a distributed network, all participants need to continuously calculate the hash value using different random numbers until the goal is reached. When one node calculates an exact value, all other nodes must confirm with each other that the value is correct. Transactions in new blocks will then be verified to prevent fraud.

In Bitcoin, the above nodes that calculate hash values ​​are called "miners", and the PoW process is called "mining". Mining is a time-consuming process, so incentives have been proposed (such as granting miners a small share of Bitcoin). The advantage of PoW is complete decentralization, but its disadvantage is the waste of resources caused by consuming a lot of computing power, the cycle of reaching consensus is also relatively long, and the consensus efficiency is low, so it is not very suitable for commercial use.

2. Application examples of cryptocurrency

Bitcoin and Litecoin. The first three phases of Ethereum (Frontier, Homestead, and Metropolis) all adopt the PoW mechanism, and its fourth phase (Serenity) will adopt the proof-of-stake mechanism. PoW is suitable for public chains.

Although the PoW mechanism has successfully proved its long-term stability and relative fairness, under the existing framework, using the "mining" form of PoW will consume A lot of energy. The energy it consumes is just to continuously perform SHA256 calculations to ensure fair workload, and has no other meaning of existence. The current transaction efficiency that BTC can achieve is about 5TPS (5 transactions/second). Ethereum is currently subject to the upper limit of the total amount of GAS in a single block, and the transaction frequency that can be achieved is about 25TPS, which is the same as the average thousand times per second and peak performance. There is a huge difference between VISA and MASTERCARD, which can achieve processing efficiency of 10,000 times per second.

3. Simple diagram understanding mode

(ps: The process of calculating hash values ​​by A, B, C, and D is "mining". In order to reward the time cost, the mechanism will use a certain number of Bitcoins as incentives.)

(Ps: In PoS mode, your "mining" income is proportional to your currency age (number of coins * number of days), andIt has nothing to do with the computing performance of the computer. We can think of any accumulation of probabilistic events as proof of work, such as gold mining. Assuming that the gold content of the ore is p% mass, when you get a certain amount of gold, we can think that you must have dug 1/p mass of ore. And the more gold you get, the more reliable the proof is. )

(2) PoS (Proof of Stake) Equity/Proof of Equity Mechanism

1. Basic introduction

PoS requires people to prove ownership of the currency amount. It believes that people with a large amount of currency are less likely to attack the network. Selection based on account balance is very unfair, as the single richest person is bound to dominate the network, so many solutions have been proposed.

In the proof-of-stake mechanism, whenever a block is created, miners need to create a transaction called "coin rights", which will be determined according to a certain Proportionately sends some coins to miners in advance. Then the equity proof mechanism reduces the mining difficulty of nodes in equal proportions based on the proportion and time of tokens held by each node (coin age) according to the algorithm, so as to speed up the node's search for random numbers and shorten the time required to reach consensus.

Compared with PoW, PoS can save more energy and be more efficient. But since the mining cost is close to 0, it may be vulnerable to attacks. And PoS still essentially requires nodes in the network to perform mining operations, so it is also difficult to apply in the commercial field.

2. Application examples of digital currency

The more mature digital currencies under the PoS mechanism are Peercoin and NXT. Compared with PoW, the PoS mechanism saves energy and introduces the concept of "coin days" to participate in random operations. The PoS mechanism allows more currency holders to participate in the accounting work without the need to purchase additional equipment (mining machines, graphics cards, etc.). The computing power of each unit token is positively related to the length of time it is held. That is, the more tokens a holder holds and the longer the time, the greater the probability that the holder can sign and produce the next block. Once it signs the next block, the currency days held by the currency holder will be cleared and a new cycle will be re-entered.

PoS is suitable for public chains.

3. How block signers are generated

Under the PoS mechanism, because the signers of blocks are randomly generated, some currency holders will hold tokens for a long time and in large amounts to obtain a greater probability of generating blocks, as many as possible To clear his "coin days". Therefore, the number of circulating tokens in the entire network will decrease, which is not conducive to the circulation of tokens on the chain, and prices will be more susceptible to fluctuations. Since there may be a small number of large investors holding most of the tokens in the entire network, the entire network may become more and more centralized as the running time increases. Compared with PoW, the cost of doing evil under the PoS mechanism is very low, so for forking or double-spending attacks, more mechanisms are needed to ensure consensus. Under stable conditions, approximately 12 transactions can be generated per second, but due to network delays and consensus issues, it takes about 60 seconds to fully broadcast the consensus block. In the long run, the speed of generating blocks (that is, clearing "coin days") is much lower than the speed of network propagation and broadcasting. Therefore, under the PoS mechanism, it is necessary to "limit the speed" of generated blocks to ensure the stability of the main network. run.

4. Simple diagram understanding mode

(PS: The more “shares” you own, the easier it is for you to obtain account rights. It refers to how much currency you get, which depends on the workload you contribute to mining and the performance of your computer. The better, the more mines will be allocated to you.)

(In a pure POS system, such as NXT, there is no mining process, and the initial equity The distribution has been fixed, and then only the equity is transferred among traders, very similar to stocks in the real world.)

(3) DPoS (Delegated Proof of Stake) ) Share authorization certification mechanism

1. Basic introduction

Due to various disadvantages of PoS , thus the DPoS (Delegated Proof of Stake), the first equity representation mechanism pioneered by BitShares, came into being. The core element of the DPoS mechanism is election. Holders of each system's native tokens can participate in elections in the blockchain, and the balance of the tokens they hold is the voting weight. Through voting, shareholders can elect board members and express their attitudes on issues related to the development direction of the platform, all of which form the basis of community autonomy. In addition to voting in elections themselves, shareholders can also vote on their behalf by authorizing their election votes to other accounts they trust.

Specifically, DPoS is powered by BitShares (Bitshares) project team invented. Stakeholders elect their representatives to generate and verify blocks. DPoS is similar to a modern corporate board of directors system. The BitShares system calls token holders shareholders, and shareholders vote to elect 101 representatives. These representatives are then responsible for generating and verifying blocks. If a currency holder wants to be called a representative, he must first use his public key to register on the blockchain and obtain a unique 32-bit identity identifier. Shareholders can vote on this identifier in the form of transactions and get votes. The top 101 people were selected as representatives.

Representatives take turns to generate blocks, and the profits (transaction fees) are equally divided. The advantage of DPoS is that it greatly reduces the number of nodes participating in block verification and accounting, thereby shortening the time required for consensus verification and greatly improving transaction efficiency. From a certain perspective, DPoS can be understood as a polycentric system, which has the advantages of both decentralization and centralization. Advantages: It greatly reduces the number of nodes participating in verification and accounting, and can achieve second-level consensus verification. Disadvantages: Voting enthusiasm is not high, and most token holders do not participate in voting; in addition, the entire consensus mechanism still relies on tokens, and many commercial applications do not require the existence of tokens.

The DPoS mechanism requires that before generating the next block, it must be verified that the previous block has been signed by a trusted node. Compared with PoS's "National Mining", DPoS uses a system similar to the "Congress" to directly select trusted nodes, and these trusted nodes (i.e. witnesses) exercise power on behalf of other currency holders. Witnesses Nodes are required to be online for a long time, thus solving a series of problems such as delays in block production that may be caused by PoS block signers not always being online. The DPoS mechanism can usually reach a transaction speed of 10,000 transactions per second, and can reach the level of 100,000 seconds when the network delay is low, which is very suitable for enterprise-level applications. Because Gongxinbao Data Exchange has high requirements for data transaction frequency and long-term stability, DPoS is a very good choice.

2. Institutions and systems under the share authorization certification mechanism

The board of directors is the authority of the blockchain network. The candidates for the board of directors are elected by system shareholders (i.e. currency holders). Board members have the right to initiate motions and vote on motions.

One of the important responsibilities of the Board of Directors is to adjust the variable parameters of the system as needed. These parameters include:

l Fee related: rates for various transaction types.

l Authorization related: parameters related to charges and subsidies for third-party platforms that access the network.

l blockProduction related: block production interval, block reward.

l Identity review related: review and verify the information of abnormal institutional accounts.

l At the same time, matters related to the interests of the Board of Directors will not be set by the Board of Directors.

In the Finchain system, witnesses are responsible for collecting various transactions broadcast when the network is running and packaging them into blocks. Their work is similar to that of the Bitcoin network In the Bitcoin network that adopts PoW (Proof of Work), a lottery method in which the probability of winning depends on the hash power determines which miner node generates the next block. In a financial chain network that adopts the DPoS mechanism, the number of witnesses is determined by voting by the board of directors, and the candidates for the witnesses are determined by voting by currency holders. The selected active witnesses package transactions and produce blocks in order. After each round of block production, the witnesses will randomly shuffle the cards to determine the new order before entering the next round of block production.

3. Application examples of DPoS

Bitshares uses DPoS. DPoS is mainly suitable for alliance chains.

4. Simple diagram understanding mode

(4) PBFT (Practical Byzantine Fault Tolerance) Practical Byzantine Fault Tolerance Algorithm

1. Basic introduction

PBFT is an algorithm based on strict mathematical proof, which requires three stages of information interaction and local consensus to achieve the final unanimous output. The three stages are pre-prepare, prepare, and commit. The PBFT algorithm proves that as long as there are more than 2/3 normal nodes in the system, it can ensure that a consistent consensus result can be output in the end. In other words, in a system using the PBFT algorithm, it can tolerate no more than 1/3 of the total number of nodes in the system (including nodes that intentionally mislead, intentionally damage the system, time out, repeatedly send messages, forge signatures, etc., also known as " Byzantium" node).

2. Application examples of PBFT

The famous alliance chain Hyperledger Fabric v0.6 uses PBFT, and v1.0 launched an improved version of PBFT, SBFT. PBFT is mainly suitable for private chains and consortium chains.

3. Simple diagram understanding mode

The above figure shows a simplified PBFT protocol communication model, where C is the client, 0 – 3 represents the service node, where 0 is the master node and 3 is the fault node . The basic process of the entire protocol is as follows:

(1) The client sends a request to activate the service operation of the master node;

(2) When the master node receives the request, it starts a three-phase protocol to broadcast the request to each slave node;

(a) Sequence number allocation phase, the master node assigns a sequence number n to the request, broadcasts the sequence number allocation message and the client's request message m, and will construct a pre-prepare message to each slave node;

(b) In the interaction phase, the slave node receives the pre-prepare message and broadcasts the prepare message to other service nodes;

(c) In the sequence number confirmation phase, after each node verifies the request and sequence in the view, it broadcasts the commit message, executes the received client request and responds to the client.

(3) The client waits for responses from different nodes. If m+1 responses are the same, the response is the result of the operation;

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(5) DBFT (Delegated Byzantine Fault Tolerance) authorized Byzantine fault tolerance algorithm

1. Basic introduction

DBFT is based on PBFT. In this mechanism, there are two types of participants, one is the "super node" who specializes in accounting , one is an ordinary user in the system who does not participate in accounting. Ordinary users vote for super nodes based on the proportion of their equity holdings. When a consensus (accounting) needs to be passed, a spokesperson is randomly selected among these super nodes to formulate a plan, and then other super nodes use Byzantine fault tolerance to algorithm (see above), that is, the principle of majority submission. If more than 2/3 of the super nodes agree with the speaker plan, a consensus is reached. This proposal becomes the final published block, and the block is irreversible, and all transactions in it are 100%Confirmed. If a consensus proposal has not been reached within a certain period of time, or if illegal transactions are discovered, other super nodes can reinitiate the proposal and repeat the voting process until a consensus is reached.

2. Application examples of DBFT

NEO, a domestic cryptocurrency and blockchain platform, is the developer and adopter of the DBFT algorithm.

3. Simple diagram understanding mode

Assume that there are only four super nodes in the system voted by ordinary users. When a consensus needs to be passed, the system will randomly select one of the representatives to speak. People make plans. The spokesperson will hand over the prepared plan to each representative. Each representative will first determine whether the speaker's calculation results are consistent with their own records, and then discuss with other representatives to verify whether the calculation results are correct. If 2/3 of the representatives unanimously agree that the calculation results of the speaker's plan are correct, then the plan is passed.

If less than 2/3 of the representatives reach a consensus, a new speaker will be randomly selected and the above process will be repeated. This system is designed to protect the system from leaders who are unable to function.

The above figure assumes that all nodes are honest and reach 100% consensus, and plan A (block) will be verified.

Given that the spokesperson is a randomly selected representative, he may be dishonest or malfunctioning . The above figure assumes that the spokesperson sends malicious messages to 2 of the 3 representatives (scenario B), and at the same time sends a correct message to 1 representative (scenario A).

In this case, the malicious information (Option B) cannot pass. The calculation results of the representatives in the middle and on the right were inconsistent with those sent by the spokesperson, so they could not verify the plan drawn up by the spokesperson, causing the two people to reject the plan. The representative on the left received correct information that was consistent with his own calculation results, so he was able to confirm the plan and successfully completed a verification. However, this plan still failed to pass because less than 2/3 of the representatives reached a consensus. A new spokesperson will then be randomly selected and the consensus process will begin again.

The above image assumes that the speaker is honest, but something went wrong with one of the representatives; the representative on the right sent incorrect information to the other representatives (B).

In this case, the correct information (A) formulated by the speaker can still be verified, because both the honest representatives on the left and the middle can verify that the correct information (A) formulated by the spokesperson The plan drawn up by the spokesperson reached a 2/3 consensus. The representative can also determine whether the speaker is lying to the node on the right or the node on the right is being dishonest.

(6) SCP (Stellar Consensus Protocol) Stellar Consensus Protocol

1. Basic introduction

SCP is a consensus algorithm developed and used by Stellar (a decentralized global payment protocol based on the Internet). It is based on the Federated Byzantine Agreement ( Federated Byzantine Agreement). Although traditional non-federated Byzantine protocols (such as PBFT and DBFT above) ensure that consensus can be reached through distributed methods and achieve Byzantine fault tolerance (can tolerate at most failed nodes that do not exceed 1/3 of the total number of nodes in the system), it is a Centralized system - The number and identity of nodes in the network must be known and verified in advance. The difference of the Federated Byzantine Agreement is that it can be decentralized and Byzantine fault-tolerant at the same time.

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(7) RPCA (Ripple Protocol Consensus Algorithm) Ripple Consensus algorithm

1. Basic introduction

RPCA is Ripple (an Internet-based Open source payment protocol, which can realize decentralized currency exchange, payment and settlement functions) consensus algorithm developed and used. In Ripple's network, transactions are initiated by the client (application) and broadcast to the entire network through the tracking node or validating node. The main function of the tracking node is to distribute transaction information and respond to client ledger requests. In addition to all the functions of the tracking node, the verification node can also add new ledger instance data to the ledger through the consensus protocol.

Ripple’s consensus occurs between verification nodes, and each verification node is pre-configured with aA list of trusted nodes is called UNL (Unique Node List). Nodes on the list can vote on the transaction. The consensus process is as follows:

(1) Each verification node will continuously receive transactions sent from the network. After verification with the local ledger data, they are illegal. The transactions will be discarded directly, and the legal transactions will be summarized into a transaction candidate set (candidate set). The transaction candidate set also includes transactions left over from the previous consensus process that could not be confirmed.

(2) Each verification node sends its own transaction candidate set as a proposal to other verification nodes.

(3) After the verification node receives a proposal from other nodes, if it is not from a node on UNL, it will ignore the proposal; if it is from a node on UNL, it will compare it with the proposal. Transaction and local transaction candidate set, if there is the same transaction, the transaction gets one vote. Within a certain period of time, when a transaction receives more than 50% of the votes, the transaction enters the next round. Transactions that do not exceed 50% will be left for the next consensus process to be confirmed.

(4) The verification node sends transactions with more than 50% of the votes as proposals to other nodes, and at the same time increases the threshold of the required votes to 60%, repeating steps (3) and (4) until the threshold Reach 80%.

(5) The verification node formally writes the transactions confirmed by 80% UNL nodes into the local ledger data, which is called the last closed ledger, which is the last (latest) status of the ledger.

In Ripple's consensus algorithm, the identities of participating voting nodes are known in advance. Therefore, the algorithm is more efficient than anonymous consensus algorithms such as PoW. Transactions The confirmation time only takes a few seconds. This also determines that the consensus algorithm is only suitable for alliance chains or private chains. The Byzantine Fault Tolerance (BFT) capability of the Ripple consensus algorithm is (n-1)/5, which means it can tolerate Byzantine errors in 20% of the nodes in the entire network without affecting the correct consensus.

2. Simple diagram understanding mode

Schematic diagram of node interaction in the consensus process:

Consensus algorithm process:

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(8) POOL verification pool consensus mechanism

Pool verificationThe certification pool consensus mechanism is a mechanism developed based on traditional distributed consensus algorithms (Paxos and Raft). The Paxos algorithm is a consensus algorithm based on message passing and highly fault-tolerant proposed in 1990. In the past, Paxos has been the standard for distributed protocols, but Paxos is difficult to understand and even more difficult to implement. Raft is a consensus algorithm released in 2013 that is simpler than Paxos and can realize the problems solved by Paxos. The process of reaching consensus in Paxos and Raft is like an election. Candidates need to convince the majority of voters (servers) to vote for them and follow their actions once selected. The difference between Paxos and Raft lies in the specific process of election. The Pool verification pool consensus mechanism is based on these two mature distributed consensus algorithms, supplemented by a data verification mechanism.

Is the coc oil blockchain legal?

No. The coc oil blockchain is crude oil investment and financial management. It is not a scam in nature. The COC certificate is a requirement of many countries. For goods exported to Saudi Arabia, Iran and other Middle East regions, the customs of the importing country requires the importer to provide a recognized international certification company for the goods. Certificate of conformity issued. Investment involves risks, please make decisions with caution.