区块链模式制度,区块链运行机制

请查看相关英文文档

❶ What are the basic knowledge about blockchain

1. Application of blockchain technology in banking industry

Blockchain technology is the largest The characteristic of is decentralization, and this feature will reduce a lot of costs for the banking industry. The development of digital currency will make it possible to realize real-time digital transactions in banks. For example, in bill transactions, bank bill transactions have always relied on a third party to realize the transfer of valuable certificates. Even electronic bill transactions require interactive authentication through information from the central bank's ECDS system. . Blockchain technology can realize point-to-point transfer of value and no longer requires centralized system control. This not only speeds up the speed of ticket transfer, but more importantly, it can reduce errors caused by human factors and reduce processes. Naturally, it will reduce the bank's demand for personnel and save the bank's labor costs.

2. Application of blockchain technology in the insurance industry

Blockchain technology also has incomparable advantages in the insurance industry. From the perspective of data management, the application of blockchain technology by insurance companies can effectively improve risk management and control capabilities, including the risk supervision of insurance companies and the risk management of policyholders.

The application of blockchain technology in the insurance industry can strengthen the internal risk supervision of insurance companies. Blockchain technology can record the daily operating processes of insurance companies on nodes, and can achieve in-process control over the company's capital flow, investment status, compensation payments and other businesses, and improve the company's risk management and control capabilities.

3. Application of blockchain technology in the securities industry

The application of blockchain technology in the securities industry can increase the flexibility of securities issuance. Companies issuing securities can use smart contracts , by setting the method and time of securities issuance, securities can even be issued 24 hours a day under the most ideal condition.

4. Blockchain technology and financial infrastructure

Blockchain technology uses a decentralized mechanism to exchange value, which will lead to a modern world characterized by centralization. Some financial infrastructures have undergone earth-shaking changes.

5. Application of blockchain technology in supply chain

The application of blockchain technology in supply chain first provides credit guarantee , the blockchain records the circulation information of commodities, etc., which can prove the true reliability of commodities and their circulation, so as to conduct a comprehensive evaluation of the utility of enterprises on the chain, etc., and has become an important factor for corporate bank loan credit, financing credit, An effective guarantee for transaction credit.

❷ 108 knowledge points for getting started with blockchain

108 essential knowledge points for getting started with blockchain

(Welcome to communicate with fellow fans)

1. What is a blockchain

Package the information of multiple transactions and the information indicating the block together. The verified package is the block.

Each block stores the hash value of the previous block, creating a relationship between blocks, that is to say, a chain. Together they are called blockchain.

2. What is Bitcoin

The concept of Bitcoin was proposed by Satoshi Nakamoto in 2009, with a total number of 21 million. The Bitcoin chain generates a block approximately every 10 minutes, and this block is mined by miners for 10 minutes. As a reward to miners, a certain number of Bitcoins will be issued to miners, but this certain number is halved every four years. Now it's 12.5. If this continues, all Bitcoins will be available in 2040.

3. What is Ethereum

The biggest difference between Ethereum and Bitcoin is the smart contract. This allows developers to develop and run various applications on it.

4. Distributed ledger

It is a database that is shared, replicated and synchronized among network members. To put it bluntly, all users on the blockchain have accounting functions and the content is consistent, which ensures that the data cannot be tampered with.

5. What is quasi-anonymity?

I believe everyone has a wallet, and the wallet address (a string of characters) used to send transactions is quasi-anonymity.

6． What is open transparency/traceability

The blockchain stores all data from history to the present, anyone can view it, and can also view any data in history.

7. What is tamper-proof

Historical data and current transaction data cannot be tampered with. The data is stored in the block on the chain and has a hash value. If the block information is modified, its hash value will also change, and the hash values ​​of all blocks following it must also be modified to form a new chain. At the same time, the main chain is still conducting transactions to generate blocks. The modified chain must always generate blocks synchronously with the main chain to ensure that the length of the chain is the same. The cost is too high, just to modify a piece of data.

8. What is anti-DDoS attack

DDoS: Hackers control many people’s computers or mobile phones and allow them to access a website at the same time. Since the bandwidth of the server is limited, a large amount of traffic The influx of data may cause the website to fail to function properly, resulting in losses. However, the blockchain is distributed and there is no central server. If one node fails, other nodes will not be affected. Theoretically, if more than 51% of the nodes are attacked, problems will occur.

9. Definition of main chain

Taking Bitcoin as an example, at a certain point in time, a block is mined by two miners at the same time, and then 6 blocks are generated first. The chain of blocks is the main chain

10. Single chain/multi-chain

A single chain refers to a data structure that handles everything on one chain. The core essence of the multi-chain structure is composed of public chain + N sub-chains. There is only one, but in theory there can be countless sub-chains, and each sub-chain can run one or more DAPP systems

11. Public chain/alliance chain/private chain

Public Chain: Everyone can participate in the blockchain

Alliance chain: Only alliance members are allowed to participate in accounting and query

Private chain: Writing and viewing permissions are only controlled by one person In the hands of the organization.

12. Consensus layer, data layer, etc.

There are six overall structures of the blockchain: data layer, network layer, consensus layer, incentive layer, contract layer, and application layer. Data layer: a layer that records data, belonging to the underlying technology; network layer: a structure for building a blockchain network, which determines how users are organized. Consensus layer: Provides a set of rules to allow everyone to reach agreement on the information received and stored. Incentive layer: Design incentive policies to encourage users to participate in the blockchain ecosystem; Contract layer: Generally referred to as "smart contracts", it is a set of contract systems that can be automatically executed and written according to their own needs. Application layer: Applications on the blockchain, similar to mobile apps. Former Distributed Storage R&D Center

13. Timestamp

The timestamp refers to the time from January 1, 1970 Day 0 hours 0 minutes 0 seconds 0... The total number of seconds from the current time to now, or the total number of nanoseconds and other very large numbers. Each block is generated with a timestamp indicating when the block was generated.

14. Block/block header/block body

Block is the basic unit of blockchain, and block header and block body are components of blockchain. The information contained in the block header includes the hash of the previous block, the hash of this block, timestamp, etc. The block body is the detailed data in the block.

15. Merkle tree

Merkle tree, also called binary tree, is a data structure for storing data. The bottom layer is the original data contained in all blocks, and the upper layer is each The hash value of a block, the hash value of this layer is combined in pairs to generate a new hash value, forming a new layer, and then upwards layer by layer, until a hash value is generated. Such a structure can be used to quickly compare large amounts of data, and you can quickly find the bottom-level historical data you want without downloading all the data.

16. What is expansion?

The size of a Bitcoin block is about 1M and can save 4,000 transaction records. Expansion means making the block larger so that more data can be stored.

17. What is a chain?

Each block will save the hash of the previous block, making the blockThere is a relationship between them, and this relationship is a chain. Data such as block transaction records and status changes are stored through this chain.

18. Block height

This is not the height mentioned in terms of distance. It refers to the total number of blocks between the block and the first block on the chain. This height indicates which block it is, and is just for identification purposes.

19. Fork

Two blocks were generated at the same time (the transaction information in the block is the same, but the hash value of the block is different), and then in Two chains are forked from these two blocks. Whoever generates 6 blocks from these two links first will be the main chain, and the other chain will be discarded.

20. Ghost Protocol

Mining pools with high computing power can easily generate blocks faster than mining machines with low computing power, resulting in most of the blocks on the blockchain being generated by these mining pools with high computing power. However, the blocks generated by mining machines with low computing power are not stored on the chain because they are slow, and these blocks will be invalid.

The ghost protocol allows blocks that should be invalidated to remain on the chain for a short time, and can also be used as part of the proof of work

. In this way, miners with small computing power will contribute more to the main chain, and large mining pools will not be able to monopolize the confirmation of new blocks.

21. Orphan blocks

As mentioned before, orphan blocks are blocks generated at the same time. One of them forms a chain, and the other does not form a chain. Then this block that does not form a chain is called an orphan block.

22. Uncle block

The orphan block mentioned above, through the ghost protocol, makes it part of the proof of work, then it will not be discarded and will be saved in the main chain superior. This block is next

23 replay attack

The hacker resends the message that has been sent to the server. Sometimes this can defraud the server of multiple responses.

24. Directed acyclic graph

Also called data set DAG (directed acyclic graph), DAG is an ideal multi-chain data structure. Most of the blockchains mentioned now are single chains, that is, one block is connected to another block, and DAG is multiple blocks connected. The advantage is that several blocks can be generated at the same time, so the network can process a large number of transactions at the same time, and the throughput will definitely increase. However, there are many shortcomings and it is currently in the research stage.

25. What is mining

The mining process is to perform a series of conversions, connections and hash operations on the above six fields, and continue to try them one by one. The random number you are looking for, and finally you successfully find a random number that meets the conditions: the value after hashing is smaller than the hash value of the preset difficulty value, then mining is successful., the node can broadcast the block to neighboring nodes. When the neighboring node receives the block, it performs the same operation on the above six fields, verifies compliance, and then broadcasts it to other nodes. Other nodes also use the same algorithm to verify , if 51% of the nodes in the entire network are successfully verified, this block will be truly "mined" successfully. Each node will add this block to the end of the previous block, and add the block to the end of the previous block. Delete the list that is the same as your own record and restart the above process again. Another thing to mention is that regardless of whether the mining is successful or not, each node will pre-record the reward of 50 Bitcoins and the handling fees of all transactions (total input-total output) in the first item of the transaction list (this is " The most fundamental purpose of "mining" is also the fundamental reason to ensure the long-term stable operation of the blockchain), the output address is the address of this node, but if the mining is unsuccessful, the transaction will be invalidated without any reward. Moreover, this transaction called "production transaction" does not participate in the "mining" calculation.

26. Mining machines/mining farms

Mining machines are computers with various configurations, and computing power is the biggest difference between them. A place where mining machines are concentrated in one place is a mining farm

27. Mining pool

Miners join together to form a team, and the computer group under this team is a mining pool. Mining rewards are distributed based on your own computing power contribution.

28. Mining difficulty and computing power

Mining difficulty is to ensure that the interval between generating blocks is stable within a certain short time, such as Bitcoin is issued in 10 minutes

p>

Block 1. The computing power is the configuration of the mining machine.

29. Verification

When verification in the blockchain is a confirmation of the legality of the transaction, each node will verify the transaction once when the transaction message is propagated between nodes. Whether the transaction is legal. For example, verify whether the syntax of the transaction is correct, whether the transaction amount is greater than 0, whether the entered transaction amount is reasonable, etc. After passing the verification, it will be packaged and handed over to the miners for mining.

30. Transaction broadcast

The node sends information to other nodes through the network.

31. Mining fees

For the blockchain to work non-stop like a perpetual motion machine, miners need to maintain the system. Therefore, the miners must be given favorable fees to make it sustainable.

32. Transaction confirmation

When a transaction occurs, the block recording the transaction will be confirmed for the first time, and will be confirmed in every area on the chain after the block. Block is reconfirmed: When the number of confirmations reaches 6 or more, the transaction is generally considered safe and difficult to tamper with.

33. Double transaction

That is, I have 10 yuan, I use the 10 yuan to buy a pack of cigarettes, and then instantly use the 10 yuan that has not yet been paid. Bought another cup of coffee. So to verify the transactionAt this time, you need to confirm whether the 10 yuan has been spent.

34. UTXO unspent transaction output

It is a data structure containing transaction data and execution code, which can be understood as digital currency that exists but has not yet been consumed.

35. Transactions per second TPS

That is throughput, tps refers to the number of transactions that the system can process per second.

36. Wallet

Similar to Alipay, it is used to store digital currencies, and blockchain technology is more secure.

37. Cold wallet/hot wallet

A cold wallet is an offline wallet. The principle is to store it locally and use QR code communication to prevent the private key from touching the Internet. A hot wallet is an online wallet. The principle is to encrypt the private key and store it on the server. When it is needed, it is downloaded from the server and decrypted on the browser side.

38. Software Wallet/Hardware Wallet

A software wallet is a computer program. Generally speaking, a software wallet is a program that interacts with the blockchain and allows users to receive, store, and send digital currencies and can store multiple keys. Hardware wallets are smart devices that specialize in handling digital currencies.

39. Airdrop

The project sends digital currency to each user’s wallet address.

40. Mapping

Mapping is related to the issuance of blockchain currency and is a mapping between chains. For example, there are some blockchain companies that have not completed the development of the chain in the early stage. They rely on Ethereum to issue their own currency. The issuance and transactions of the early currency are all operated on Ethereum. With the development of the company, the company's own chain development has been completed. The company wants to map all the previous information on Ethereum to its own chain. This process is mapping.

41. Position

Refers to the ratio of the investor’s actual investment to the actual investment funds

42. Full position

All funds are bought Enter Bitcoin

43. Reduce the position

Sell some of the Bitcoins, but not all of them

44. Heavy positions

Compared with Bitcoin, Bitcoin accounts for a larger share of funds

45. Short position

Compared with Bitcoin, the share of funds is larger

46. Short position

Sell all the Bitcoins you hold and convert them all into funds

47. Stop loss

After obtaining a certain profit, sell the Bitcoin held to keep the profit

48. Stop loss

After losses reach a certain level, sell the Bitcoins you hold to avoidStop losses from further expansion

49. Bull market

Prices continue to rise and the outlook is optimistic

50. Bear market

Prices continue to fall and the outlook is bleak

51. Long (going long)

The buyer believes that the currency price will rise in the future, buys the currency, and after the currency price rises, sells it at a high price to take profits

52. Short position (short selling)

The seller believes that the currency price will fall in the future, and sells the currency he holds (or borrows currency from the trading platform). After the currency price drops, the seller will sell the currency at a low price. Buy and take profits

53. Open a position

Buy Bitcoin and other virtual currencies

54. Cover the position

Buy in batches Bitcoin and other virtual currencies, for example: buy 1 BTC first, then buy 1 BTC

55. Full position

Buy all the funds into a certain virtual currency at one time< /p>

56. Rebound

When the currency price falls, the price rebounds and adjusts because it falls too fast

57. Consolidation (sideways)

The price fluctuation range is small and the currency price is stable

58. Overcast drop

The currency price declines slowly

59. Diving (waterfall)

The currency price fell rapidly and to a large extent

60. Cutting meat

After buying Bitcoin, the currency price fell. In order to avoid expanding the loss, the Bitcoin was sold at a loss. Or after borrowing the currency to go short, the currency price rises, and then buying Bitcoin at a loss

61. Holding up

Expecting the currency price to rise, but unexpectedly the currency price falls after buying; or expecting the currency price to rise. fell, but unexpectedly, after selling, the currency price rose

62. Unwinding

After buying Bitcoin, the currency price fell, causing a temporary book loss, but then the currency price rebounded and the loss was reversed To make a profit

63. Go short

After selling Bitcoin because of the bearish market outlook, the price of the currency continued to rise, and I was unable to buy it in time, so I failed to make a profit

64. Overbought

The currency price continues to rise to a certain height, the buyer's power is basically exhausted, and the currency price is about to fall

65. Oversold

The currency price continues to fall to a certain low, the seller's power is basically exhausted, and the currency price is about to rise

66. Lure bulls

The currency price has been consolidating for a long time, and it is more likely to fall. Most of the short sellers have sold Bitcoin, and suddenly the short sellers pulled up the price of the currency, inducing the long parties to think that the price of the currency will rise and buy one after another. As a result, the short sellers suppressed the price of the currency and locked up the long parties.

67. Short-selling

After buying Bitcoin, bulls deliberately suppress the price of the currency, making short sellers think that the price of the currency will fall and sell them one after another. As a result, they fall into the trap of bulls

68. What is NFT

The full name of NFT is "Non-Fungible Tokens", which is non-fungible tokens. Simply put, it is a token on the blockchain. This kind of indivisible copyright certificate is mainly used to confirm and transfer the rights of digital assets. The difference from digital currency is that it is unique and indivisible. In essence, it is a unique digital asset.

69. What is the Metaverse

The Metaverse is a collection of virtual time and space, consisting of a series of augmented reality (AR), virtual reality (VR) and the Internet (Internet) Composed of digital currency, which carries the function of value transfer in this world.

70. What is DeFi

DeFi, the full name is Decentralized Finance, which is "decentralized finance" or "distributed finance". "Decentralized finance", as opposed to traditional centralized finance, refers to various financial applications based on open decentralized networks. The goal is to establish a multi-level financial system based on blockchain technology and cryptocurrency. As a basis, re-create and improve the existing financial system

71. Who is Satoshi Nakamoto?

Satoshi Nakamoto is the developer and founder of Bitcoin. Satoshi Nakamoto published the Bitcoin white paper on November 1, 2008, and mined Bitcoin for the first time on January 3, 2009. Whoever can use the Bitcoin in the genesis block is Satoshi Nakamoto himself, so who Is it Satoshi Nakamoto? There have been many "Satoshi Nakamotos" in history: In 2013, someone revealed that Mochizuki Shinichi, who had made outstanding contributions in the field of mathematics, was Satoshi Nakamoto, but no direct evidence was provided. In 2014, hackers hacked into the email address used by Satoshi Nakamoto and found the owner of the email, Dorian Nakamoto. Later, Dorian said that he only obtained the email address and password by chance, not Nakamoto. Cong. In 2016, Craig Wright said that he was Satoshi Nakamoto and could provide Satoshi Nakamoto's private key. But later, Wright withdrew his statement because he could not face everyone's doubts.

72. Bitcoin is different from Q Coin

Bitcoin is a decentralized digital asset with no issuing entity. Q Coin is an electronic currency issued by Tencent. It is similar to electronic points, but it is not actually a currency. Q Coin requires a centralized issuing institution. Q Coin can only be recognized and used because of the credit endorsement of Tencent. The scope of use is also limited to Tencent’s games and services, and the value of Q coins is completelyIt’s all based on people’s trust in Tencent.

Bitcoin is not issued through a centralized institution, but it is widely recognized around the world because Bitcoin can self-certify its trust. The issuance and circulation of Bitcoin are jointly accounted for by miners across the entire network, and are not A central authority is also needed to ensure that no one can tamper with the ledger.

73. What is a mining machine?

Taking Bitcoin as an example, a Bitcoin mining machine is a professional equipment that competes for accounting rights by running a large amount of calculations to obtain new Bitcoin rewards. It is generally composed of a mining chip, a heat sink and a fan, and only performs A single calculation program consumes a lot of power. Mining is actually a competition between miners for computing power. Miners with more computing power have a greater probability of mining Bitcoin. As the computing power of the entire network increases, it becomes increasingly difficult to mine bits with traditional equipment (CPU, GPU), and people have developed chips specifically for mining. The chip is the core part of the mining machine. The operation of the chip will generate a large amount of heat. In order to dissipate heat, Bitcoin mining machines are generally equipped with heat sinks and fans. Users download Bitcoin mining software on their computers, use the software to assign tasks to each mining machine, and then start mining. Each currency has a different algorithm and requires different mining machines.

74. What is quantitative trading?

Quantitative trading, sometimes also called automated trading, refers to the use of advanced mathematical models to replace human subjective judgments, which greatly reduces the impact of investor sentiment fluctuations and avoids extreme fanaticism or pessimism in the market. make irrational investment decisions. There are many types of quantitative trading, including cross-platform trading, trend trading, hedging, etc. Cross-platform trading means that when the price difference between different target platforms reaches a certain amount, sell on the platform with a higher price and buy on the platform with a lower price.

75. Blockchain asset over-the-counter trading

Over-the-counter trading is also called OTC trading. Users need to find their own counterparties and do not need to match the transaction. The transaction price is determined by negotiation between the two parties. The two parties can fully communicate through face-to-face negotiation or telephone communication.

76. What is a timestamp?

The blockchain ensures that each block is connected sequentially through timestamps. Timestamps enable every piece of data on the blockchain to have a time stamp. Simply put, timestamps prove when something happened on the blockchain and cannot be tampered with by anyone.

77. What is a blockchain fork?

Upgrading software in a centralized system is very simple, just click "Upgrade" in the app store. However, in decentralized systems such as blockchain, "upgrading" is not that simple, and a disagreement may even cause a blockchain fork. Simply put, a fork refers to a disagreement when the blockchain is "upgraded", resulting in a fork in the blockchain. Because there is no centralized organization, every code upgrade of digital assets such as Bitcoin needs to be unanimously recognized by the Bitcoin community. If the Bitcoin communityIf consensus cannot be reached, the blockchain is likely to fork.

78. Soft fork and hard fork

Hard fork means that when the Bitcoin code changes, the old nodes refuse to accept the blocks created by the new nodes. Blocks that do not comply with the original rules will be ignored, and miners will follow the original rules and create new blocks after the last block they verified. A soft fork means that old nodes are not aware of the changes to the Bitcoin code and continue to accept blocks created by new nodes. Miners may work on blocks they have no understanding of, or validation of. Both soft forks and hard forks are "backwards compatible" to ensure that new nodes can verify the blockchain from scratch. Backward compatibility means that new software accepts data or code generated by old software. For example, Windows 10 can run Windows XP applications. Soft forks can also be "forward compatible".

79. Classification and application of blockchain projects

Judging from the current mainstream blockchain projects, blockchain projects mainly fall into four categories: Category 1: Currency; The second category: platform category; the third category: application category; the fourth category: asset tokenization.

80. USDT against the US dollar

USDT is Tether USD, a token launched by Tether that is against the US dollar (USD). 1USDT=1 US dollar, users can use USDT and USD for 1:1 exchange at any time. Tether implements a 1:1 reserve guarantee system, that is, each USDT token will have a reserve guarantee of 1 US dollar, which supports the stability of the USDT price. The unit price of a certain digital asset is USDT, which is equivalent to its unit price in US dollars (USD).

81. Altcoins and alternative coins

Altcoins refer to blockchain assets that use the Bitcoin code as a template and make some modifications to its underlying technology blockchain, among which Those with technological innovations or improvements are also called alternative coins. Because the Bitcoin code is open source, the cost of plagiarism in Bitcoin is very low. You can even generate a brand new blockchain by simply copying the Bitcoin code and modifying some parameters.

82. Three major exchanges

Binance

Okex

Huobi

83. Market software

Mytoken

Non-small account

84. Information website

Babbitt

Golden Finance

Coin World News

85. Blockchain Browser

BTC

ETH

BCH

< p> LTC

ETC

86. Wallet

Imtoken

Bitpie

MetaMask (Little Fox)

87. Decentralization Exchange

uniswap

88. NFT Exchange

Opensea

Super Rare

89. Ladder

Bring your own, buy a reliable ladder

90. Platform currency

The digital currency issued by the platform, use For deducting handling fees, transactions, etc.

91. Bull market, bear market

Bull market: rising market

Bear market: falling market

92 . Blockchain 1.0

A currency trading system based on distributed ledgers, represented by Bitcoin

93. Blockchain 2.0

Ethereum (smart contract ), the contract blockchain technology represented by 2.0

94. Blockchain 3.0

In the era of intelligent Internet of Things, it goes beyond the financial field to provide decentralized solutions for various industries.

95. Smart Contract

Smart Contract is a computer protocol designed to spread, verify or execute contracts in an information-based way. Simply put, an electronic contract is set in advance , once confirmed by both parties, the contract will be automatically executed.

96. What is a token?

The token economy is an economic system with Token as the only reference standard, which is equivalent to a pass. If you own Token, you have rights and interests, and you have the right to speak.

97. The difference between big data and blockchain

Big data is the means of production, AI is the new productivity, and the blockchain is the new production relationship. Big data refers to a collection of data that cannot be captured, managed and processed within a certain time range using conventional software tools. It is a massive, high-growth and high-volume data set that requires new processing models to have stronger decision-making power, insight discovery and process optimization capabilities. Diverse information assets. Simply understood, big data is massive data accumulated over a long period of time and cannot be obtained in the short term. Blockchain can be used as a way to obtain big data, but it cannot replace big data. Big data is only used as a medium running in the blockchain and has no absolute technical performance, so the two cannot be confused. (A simple understanding of production relations is labor exchange and consumption relations. The core lies in productivity, and the core of productivity lies in production tools)

98. What is ICO?

ICO, Initial Coin Offering, is the initial public offering of tokens, which is crowdfunding in the blockchain digital currency industry. It is the most popular topic and investment trend in 2017, and the country launched a regulatory plan on September 4. Speaking of ICO, people will think of IPO, and the two are fundamentally different.

99. Five characteristics of digital currency

The first characteristic: decentralization

The second characteristic: having open source code

The third feature: independent electronic wallet

The fourth feature: constant issuance

The fifth feature: global circulation

100. What is decentralization?

It has no issuer, does not belong to any institution or country, and is a publicly issued currency designed, developed and stored on the Internet by Internet network experts.

100. What is measurement (scarcity)?

Once the total amount of issuance is set, it is permanently fixed, cannot be changed, cannot be over-issued at will, and is subject to global Internet supervision. Because the difficulty of mining and mining changes over time, the longer the time, the greater the difficulty of mining, and the fewer coins are mined, so it is scarce.

101. What is open source code?

The alphanumeric code is stored on the Internet. Anyone can find out the source code of its design, everyone can participate, can mine it, and it is open to the world.

102. What is anonymous transaction? Private wallet private?

Everyone can register and download the wallet online without real-name authentication. It is completely composed of encrypted digital codes. It can be sent and traded globally in real-time point-to-point without resorting to banks or any institutions. It cannot be traced by anyone without my authorization. ,Inquire.

103. What is a contract transaction?

A contract transaction refers to an agreement between a buyer and seller to receive a certain amount of an asset at a specified price at a certain time in the future. The objects of contract trading are standardized contracts formulated by the exchange. The exchange stipulates standardized information such as commodity type, transaction time, quantity, etc. A contract represents the rights and obligations of the buyer and seller.

104. Digital Currency Industry Chain

Chip manufacturers, mining machine manufacturers, and mining machine agents mine and export to exchanges for retail investors to speculate in coins< /p>

105. Who is Bei Feng?

Beifeng: Digital currency value investor

Investment style: Steady

106. Build a community?

Beidou Community (high-quality price investment community)

Combining long-term and short-term, focusing on price investment, no touching contracts, no short-term play

Reasonable layout, scientific operation, steady and conservative, making periodic money

Welcome currency friends and seek common development.

❸ Blockchain consensus mechanism POS and DPOS

As the first consensus mechanism in the blockchain and one that has withstood sufficient practical testing, the workload proof algorithm solves the following problems: The issue of consistency of transaction information in distributed systems builds a trust mechanism for nodes that do not trust each other in a decentralized network, and is also a key technical link for the successful application of Bitcoin.

After several years of actual operation, the shortcomings of this algorithm have also been revealed. The Bitcoin network completes 600 trillion SHA256 operations per second, consuming a large amount of power resources. In the end, these calculations have no practical effect. or scientific value. The only purpose of these operations is to solve the proof-of-work problem. Another real threat is the concentration of computing power. Proof-of-work is essentially a process of using exhaustive methods to find hash values ​​that meet specified conditions. The stronger it is, the higher the possibility of obtaining accounting rights (that is, mining). At first, it was the first people to use graphics cards to mine, and later to use FPGA mining machines, and then to use ASIC special chips to mine. People are now the ones who are constantly making better ASICs. In addition, there are "miner" nodes that unite to form mining pools, such as Ghash. Ghash issued a statement in 2014 that it will ensure that no more than 40% of the computing power of the entire network will be exceeded in the future. , this kind of self-discipline statement is a great irony of Bitcoin’s trustless mechanism.

Since the birth of Bitcoin, people have begun to try other consensus mechanisms besides the proof-of-work algorithm, such as the representative proof-of-stake POS, delegated proof-of-stake DPOS, and Byzantine Fault Tolerance (BFT). and Practical Byzantine Fault Tolerance (PBFT), etc. Below we will mainly introduce POS and DPOS, leaving BFT and PBFT for the next article.

Proof of Stake POS

POS is a type of consensus algorithm, or the design idea of ​​a type of consensus algorithm, not one. The first to adopt POS was Peercoin. Peercoin is a type of cryptocurrency launched by a geek with the pseudonym Sunny King in August 2012. It adopts the proof-of-work mechanism + the proof-of-stake mechanism, and introduces the proof-of-stake mechanism into cryptocurrency for the first time. Peercoin introduces the concept of "coin age". Each coin generates 1 coin age every day. For example, if you hold 100 coins for a total of 30 days, then your coin age will be 3000 at this time. When a new block is generated, other nodes that want to obtain accounting rights also need to calculate the hash value of Bitcoin. The difficulty of obtaining the hash value that meets the conditions is related to the difficulty value. This difficulty value here is related to the age of the currency. Inversely proportional, that is, the older your currency is, the moreThe higher the probability of generating a hash value that meets the conditions. At the same time, your currency age is cleared, and the system will give you corresponding "interest" after accounting. For every 365 currency ages you are cleared, the interest you receive is: 3000 * interest rate / 365 , the interest rate of Peercoin is 1%, which is 0.08 coins.

It can be seen that under the POS mechanism, the more coins you hold, the easier it is to obtain accounting rights, which is close to the winner-takes-all feeling. But the more coins you hold, the closer it is to an honest person. nodes, the greater the loss caused by destroying the entire network. There is a loophole in Peercoin's POS mechanism. For people who do not hold coins, they have little benefit, so some malicious attacks have no loss for them. This is a Nothing-at-stake attack. Subsequent more successful POSs have introduced mechanisms to deal with this kind of attack.

The Ethereum system aims to introduce proof of stake, known as Casper, this year. Under the proof-of-stake consensus mechanism, users will be able to have “currency rights” in the Ethereum network. Users who act honestly and confirm legitimate transactions will receive interest proportional to their equity; users who act maliciously and attempt to cheat the network will lose their equity.

Delegated Proof of Equity DPOS

Delegated Proof of Equity DPOS is a variant of POS. Typical examples of using DPOS are BitShares. The basic principle is that the entire network votes to select 101 node agents. Account permissions, the permissions of these representative nodes are exactly the same. The representative nodes take turns keeping accounts and can choose to create blocks or not. But they cannot change the details of the transaction, and the behavior of malicious or late representative nodes will be made public, and the network may vote them out simply and quickly. Representative nodes that are expelled will lose their accounting rights and corresponding income.

As a weakly centralized consensus mechanism, DPOS retains some key advantages of centralized systems, such as transaction speed (the time of each block is 10 seconds, and a transaction gets 6- It takes about 1 minute after 10 confirmations, and a complete 101 block cycle only takes about 16 minutes), but each currency holder has the ability to decide which nodes can be trusted, and in fact, representative nodes will actively lower their own To win more votes, the remaining income will be paid as dividends to all BitShares holders. DPOS is somewhat similar to representative democracy and the joint-stock company board of directors system. It is an elite system, but its identity is subject to the people below. In DPOS, the holders of the currency at least have the right to decide the identity of the representative node-or miner.

❹ Blockchain Information Service Management Regulations

Article 1 is to regulate blockchain information service activities, safeguard national security and social public interests, and protect the rights and interests of citizens, legal persons and other organizations. Legitimate rights and interests, promote the healthy development of blockchain technology and related services, according to the "ChinaThese regulations are formulated in accordance with the Cybersecurity Law of the People's Republic of China, the Measures for the Administration of Internet Information Services, and the Notice of the State Council on Authorizing the Cyberspace Administration of China to Responsible for the Management of Internet Information Content. 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 supervision, management and law enforcement of blockchain information services within their respective administrative regions according to their responsibilities. 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 , copying, publishing, disseminating prohibited by laws and administrative regulationsinformation. 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 Blockchain information service providers that have completed registration shall indicate their registration number in a prominent position on the Internet websites, applications, etc. that provide services to the outside world. 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; if they refuse to make corrections or the circumstances are serious, they shall also 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 Blockchain information service providers violateViolations of the provisions of Articles 8 and 16 of these Provisions shall be handled by the Internet Information Office of the country and provinces, autonomous regions, and municipalities directly under the Central Government in accordance with their duties and in accordance with the provisions of the Cybersecurity Law of the People's Republic of China. 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 regulations 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 If a blockchain information service provider violates the provisions of Article 11, Paragraph 1 of these Regulations, fails to perform registration procedures in accordance with these Regulations or fills in false registration information, the Internet Information Office of the country, province, autonomous region, or municipality directly under the Central Government shall In accordance with their duties, they shall be ordered to make corrections within a time limit; if they refuse to make corrections or the circumstances are serious, they shall 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 20 working days from the date when these regulations come into effect. Article 24 These regulations will come into effect on February 15, 2019.

❺ After reading this article, you will have a thorough understanding of the blockchain

In this article, all the content I introduced is about the blockchain in today’s world. The fact that the blockchain field has already happened is not some imagination or opinions about the blockchain. I think that as long as you read this article carefully, you will easily have a basic and accurate understanding of blockchain.

The main content of understanding blockchain in just ten minutes is divided into four sections. 21 topics and 4 sections are:

The first national blockchain strategy.

Second, Bitcoin and its literal representation involve four topics.

Third, blockchain and its technical logic involve 13 topics.

Fourth, blockchain empowers the economy and society, involving three topics.

Let’s first look at the first part of the blockchain national strategy, the first part of the blockchain country. Everyone knows that we humans have experienced six information revolutions. Seven or eight years ago, the first information revolution created primitive language, social tacit understanding, and the second information revolution saw the emergence of writing. The third information revolution in feudal society invented papermaking and printing, and the fourth information revolution in the late 19th century invented radio.

20th centuryIn the fifth information revolution, television appeared again, and now in the sixth information revolution, computers and the Internet have appeared. The emergence of computers and the Internet has given rise to the rapid development of various new technologies. Especially in 2020, the digital economy has experienced epoch-making development.

Why do you say that? The characteristics of high bandwidth, low latency and large connections in the 5G era have enabled the implementation of the four major ABCD technologies.

What are the four major ABCD technologies

The a here refers to Artificial Intelligence, which is artificial intelligence technology.

B refers to Blockchain, blockchain technology.

C refers to cloud computing cloud computing technology

D refers to big data technology.

The word blockchain is now completely popular all over the country. On October 25, 2019, the Political Bureau of the Central Committee of the Communist Party of China announced the development of blockchain technology. The current situation has been collectively studied, so the requirement of this meeting is to use blockchain technology as the core technology.

As an important breakthrough for independent innovation, it is necessary to accelerate the innovative development of blockchain technology and industry. On April 20, 2020, the National Development and Reform Commission officially included blockchain into new infrastructure. Blockchain, why do you think it is so awesome? Let us say that blockchain is not an extension of the Internet, it is a subversion of the Internet. In the future, many, many technologies will grow on this blockchain and realize blockchainization.

So, how can we accurately learn and understand the blockchain?

We found that among the four major technologies of ABCD, only the block is naturally built-in It's financial. Therefore, we must learn and understand blockchain from the IT perspective and the financial perspective, and even learn and understand blockchain from the level of national governance. If you only study and understand blockchain from an IT perspective, it is impossible to understand the huge influence and influence of this technology. Then, your understanding of this will be biased. Even more, you may disapprove of blockchain technology. In addition, in the process of learning about blockchain, you should also pay attention to the fact that it has many new terms, so you need to concentrate on understanding it step by step.

Let’s first understand blockchain from a financial perspective.

Bitcoin and its launch performance

To understand the blockchain, it involves Bitcoin, and the birth of Bitcoin is inseparable from the evolution of currency. We know that currency is separated from commodities and is a fixed special commodity that serves as a general equivalent. . In fact, we humans have used a lot of currencies, including physical currency, weighing currency, paper money, accounting currency, etc. As for accounting currency, it includes electronic currency and digital currency. Electronic currency itself is not a currency. It is just used to represent the same amount of currency. It is a token.

Then the total amount of his tokens will not increase due to the increase of electronic currency. Alipay, WeChat, payment, and online banking are typical electronic currencies. As for digital currency, it is itself a legal currency. The total amount of this fiat currency will increase with the increase of digital currency. We know that when it comes to physical currency, we humans have actually chosen many things as general equivalents.

Weighing currencies are some heavy metals. Later, people chose gold among the heavy metals. Why choose gold? Because gold has the characteristics of rarity, divisibility, and the most stable chemical properties. What needs to be noted here is gold. It is not issued by any country. It is provided by nature. of. Your country's total amount is as much as nature provides. Therefore, the country does not need to provide credit guarantees for the value of gold.

However, as for gold, it has some flaws in its use, and it is difficult to carry when you go out again, so there are descendants. Paper money appeared in the Northern Song Dynasty. At that time, paper money was not currency in the current sense. The currency at that time was still gold, but we used paper money to represent gold. We called it the gold standard. The gold standard is the gold standard, which is a monetary system with gold as the standard currency. The core essence of the gold standard is that how much currency a country issues should be decided based on how much gold your country has. It does not mean you can issue as much currency as you want.

At that time, the Great Depression of the United States reached January 10, 1934. On this day, the newly elected President of the United States made a very important decision to abandon the gold standard and issue $3 billion. Think about it, abandoning the gold standard, in theory, means that he can issue as much currency as he wants. Even if there is no gold in the treasury, he can issue banknotes as long as he wants to. Then someone will ask, if you issue so many words, can you still exchange them for gold of equal value?

Look at the banknotes at this time, they have been separated from gold, and national credit has emerged. , this, we call it currency guaranteed by national credit. Now, when mainstream countries issue currency, they also use national credit as a guarantee.of.

What are the benefits? The advantage is that it can regulate the economy. When the economy is not doing well, a little more hair can drive economic development. The increase or decrease in this variable will cause a chain reaction of the entire economic aggregate. This is the multiplier effect in economics. Once a country masters this thing, some countries will be fascinated by it. But if it is not well controlled, it will lead to national credit bankruptcy. As a result, many people began to reflect. This reflection is, when issuing currency, is it better to use national credit as a guarantee, or is it better to stick to the gold standard based on the total amount of gold. This question involves the birth of Bitcoin

❻ What is the consensus mechanism of the blockchain?

How to achieve consensus in a decentralized network? In the blockchain system, there is no centralized accounting institution like a bank. It is crucial to ensure the consistency of each transaction on all accounting nodes, that is, to achieve consensus across the entire network. The consensus mechanism solves this problem. At present, the main consensus mechanisms include the proof-of-work mechanism PoW and the proof-of-stake mechanism PoS. PoW determines your probability of obtaining accounting rights by evaluating your workload. The greater the workload, the more likely you are to obtain this accounting opportunity. PoS determines your probability of obtaining accounting rights by evaluating the number and length of time you hold tokens. This is similar to the dividend system of stocks. People who hold relatively large shares can receive more dividends. The principle of DPOS is similar to that of POS, except that some "people's congress representatives" are selected. The main difference from PoS is that nodes elect several agents, who verify and keep accounts. With the development of technology, more advanced consensus mechanisms may be born in the future.

❼ What is the six-layer model of the blockchain?

The blockchain has a total of six levels of structure. These six levels of structure from bottom to top are: data layer, network layer , consensus layer, incentive layer, contract layer, and application layer.
1. Data Layer
The data layer is the bottom layer of the six-level structure of the blockchain. We can understand the data layer as a database, but for blockchain, this database is an immutable and distributed database, which is what we call a "distributed ledger".
On the data layer, that is, on this "distributed ledger", the data information on the blockchain is stored, encapsulating the blockchain structure of the block, asymmetric encryption technology, hash algorithm and other technologies Means to ensure the security of data when it is disclosed to the entire network. The specific approach is:
On the blockchain network, nodes use consensus algorithms to maintain the consistency of data in the data layer (that is, this distributed database), using asymmetric encryption and hash algorithms in cryptography. , to ensure that this distributed database cannot be tampered with and is traceable.
This constitutes the lowest level data structure in blockchain technology. However, it is not enough to have a distributed database. The data information in the database also needs to be shared and exchanged., below we introduce the upper layer of the data layer-the network layer.
2. Network layer
The network system of the blockchain is essentially a P2P (point-to-point) network. Point-to-point means that there is no need for an intermediate link or centralized server to control the system. Everything in the network Resources and services are allocated to each node, and information can be transmitted directly between the two nodes. However, it should be noted that P2P
(peer-to-peer) was not invented by Satoshi Nakamoto. Blockchain just incorporates this technology.
So, the network layer of the blockchain is actually a particularly powerful peer-to-peer network system. In this system, each node can both produce and receive information, just like sending emails. You can write your own emails or receive emails sent to you by others.
On the blockchain network, nodes need to jointly maintain the blockchain system. Whenever a node creates a new block, it needs to notify other nodes in the form of broadcast, and other nodes receive After receiving the information, the block is verified, and then a new block is created based on the block. In this way, the entire network can jointly maintain and update the general ledger of the blockchain system.
However, what rules should the entire network follow to maintain and update the general ledger of the blockchain system? This involves the so-called "laws and regulations" (rules), which is what we will introduce next: the consensus layer.
3. Consensus Layer
In the world of blockchain, consensus, simply put, means that the entire network must maintain and update the general ledger of the blockchain system according to a unified and agreed-upon rule. Similar to the rules for updating data. Allowing highly dispersed nodes to efficiently reach consensus in a decentralized blockchain network is one of the core technologies of the blockchain and is also the governance mechanism of the blockchain community.
The current mainstream consensus mechanism algorithms include: Bitcoin's Proof of Work (POW), Ethereum's Proof of Stake
(POS), EOS's Delegated Proof of Stake (DPOS), etc.
We have now introduced the data layer, network layer, and consensus layer. These three layers ensure that there is data and network on the blockchain, and there are rules for updating data on the network. However, there is no free lunch in the world. How to make it happen? Nodes can actively participate in the maintenance of the blockchain system. This involves incentives, which is what we will introduce below: the incentive layer.
4. Incentive layer
The incentive layer is the so-called mining mechanism. The mining mechanism can actually be understood as an incentive mechanism: how much you contribute to the blockchain system, you can get as many rewards as you want. Using this incentive mechanism, nodes across the entire network can be encouraged to participate in data recording and maintenance on the blockchain.
The mining mechanism and the consensus mechanism are actually the same. The consensus mechanism can be understood as the company's general rules and regulations, and the mining mechanism can be understood as, within this general rules and regulations, what you have done can What kind of reward do you get? This kind of rewardrule.
Just like Bitcoin’s consensus mechanism PoW, its stipulation is that the more work you do, the more you gain. Whoever can find the correct hash value first can get a certain amount of Bitcoin rewards;
And Ethereum PoS stipulates that the longer who holds the currency, the greater the probability of receiving rewards.
It should be noted that the incentive layer is generally only available in public chains, because public chains must rely on nodes across the entire network to jointly maintain data, so there must be such an incentive mechanism to encourage nodes throughout the network to participate in the blockchain system. Construction and maintenance to ensure the security and reliability of the blockchain system.
The blockchain is safe and reliable, but it is not smart enough, right? The contract layer we will introduce below can make the blockchain system more intelligent.
5. Contract Layer
The contract layer mainly includes various scripts, codes, algorithm mechanisms and smart contracts, and is the basis for blockchain programmability. The "smart contract" we are talking about belongs to the contract layer.
If the Bitcoin system is not smart enough, then the "smart contracts" proposed by Ethereum can meet many application scenarios. The principle of the contract layer is mainly to embed code into the blockchain system and use this method to implement customizable smart contracts. In this way, on the blockchain system, once the terms of the smart contract are triggered, the system can automatically execute the order.
6. Application Layer
The last is the application layer. The application layer is very simple. As the name suggests, it is the various application scenarios and cases of blockchain. The "blockchain+" we are talking about now is the so-called application layer. The blockchain applications that have been implemented so far are mainly various blockchain applications built on public chains such as ETH and EOS. There are many gambling and game applications, and truly practical applications have not yet appeared.

❽ Blockchain and its security mechanism

Blockchain technology has been mainly used in virtual currencies so far. The main example is the Bitcoin system. Blockchain is a distributed database composed of consecutive blocks. , containing multiple pieces of information. (Multiple nodes back up the same data and maintain continuous transaction files). The blockchain has no managers and no center at all. If the center conducts transactions, the biggest worry is the security of the transaction. Today's The editor introduces the blockchain and its security mechanism.

Characteristics of centralized and distributed transactions

Blockchain is a distributed database with centralized characteristics. The following examples are centralized in financial systems Comparison with the split-bridge type. For red, yellow and blue, according to the traditional financial mechanism, transactions must be conducted through banks. However, after adopting the distributed block-sensitive chain model, there is no need to conduct autonomous transactions through banks. Transaction.

(1) Centralized model:

1) Transactions through financial institutions such as banks

2) Banks uniformly manage information such as balances and account numbers< /p>

3) It is necessary to open an account in advance and obtain an ID card.

4) Security depends on the bank, and fraudulent banks need to be checked through various regulations and systems.is.

(2) Distribution model:

1) Transact with users on the P2P network

2) The address is managed by the participants themselves, and the balance is Globally shared distributed ledger management

3) You need to install software and connect to the P2P network

❾ Consensus mechanism of blockchain

1. Block The goal of the chain consensus mechanism

What is the 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, and everyone’s ledgers are synchronized through a peer-to-peer network. 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 security.

p>

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. Qualifications for participating nodes will be strictly restricted. Since 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

p>

l Pool verification pool consensus mechanism

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

< br />

1. Basic introduction

In this mechanism, every node on the network is using the SHA256 hash function (hash function) calculates a constantly changingThe hash sum of the 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. 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, the use of PoW's "mining" form will consume A lot of energy. The energy it consumes is just to continuously perform SHA256 calculations to ensure a 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 the hash value of 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 the age of your currency (number of coins * number of days), and has nothing to do with the computing performance of the computer. We can think of any probabilisticThe accumulation of events is 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 highly 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 to generate block signers

Under the PoS mechanism, Because the signature of the blockThe signers are randomly generated, so some currency holders will hold the tokens for a long time and in large amounts to obtain a greater probability of generating blocks, and to clear as many of their "coin days" as possible. 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 (i.e. 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 was invented by the Bitshares project team. Equity owners elect their representativestable to generate and verify blocks. DPoS is similar to a modern corporate board of directors system. The BitShares system refers to token holders as 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 times 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 Block production 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 HyperledgerFabric v0.6 uses PBFT, and v1.0 introduces 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;

p>

(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 who does not participate in accounting in the system. 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 an agreed proposal has not been reached within a certain period of time, orIf an illegal transaction is discovered, other super nodes can re-initiate 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 picture assumes that the speaker is honest, but One of the representatives had an abnormality; the representative on the right informed the other representativesIncorrect information was sent (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.

[…]

(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. Each verification node is pre-configured with a list of trusted nodes, 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:

< br />

(8) POOL verification pool consensus mechanism

Pool verification pool The consensus mechanism is based on the traditional distributed consensus algorithm (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.

❿ What are the core blockchain technologies of blockchain technology?

What is the hottest topic on the Internet right now? You don’t need to tell me what the editor is saying. , that is blockchain technology, but many friends have only heard of this technology and do not have much in-depth understanding of it. So what are the blockchain technologies? Below we will bring you an introduction to the core technology of blockchain for your reference.
What are the core elements of blockchain technology?
Blockchain technology can be a public ledger (visible by anyone) or a permissioned network (visible only by those authorized), which solves supply chain challenges , because it is an immutable record that is shared among network participants and updated in real time.
Blockchain technology----data layer: designing the data structure of the ledger
Core technology 1. Block + chain:
Technically speaking, block is a data structure that records transactions. Reflects 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.
Each block consists of a block header and a block body. The block body is only responsible for recording all transaction information in the previous period, mainly including the number of transactions and transaction details; the block header encapsulates the current version number, previous A block address, timestamp (recording the time when the block was generated, accurate to the second), random number (recording the value of decrypting the answer to the math question related to the block), the target hash value of the current block, and the Merkle number Root value and other information. From a structural point of view, most functions of the blockchain are implemented by the block header.
Core technology 2. Hash function:
The hash function can convert data of any length into a set of fixed-length codes through the Hash algorithm. The principle is based on a cryptographic one-way hash function. This function is easy to verify, but it is veryDifficult to crack. Usually, the industry uses y=hash(x) to represent it. This hash function implements operations on x to calculate a hash value y.
Commonly used hash algorithms include MD5, SHA-1, SHA-256, SHA-384 and SHA-512, etc. Taking the SHA256 algorithm as an example, inputting any string of data into SHA256 will result in a 256-bit Hash value (hash value). Its characteristics: the same data input will get the same result. As long as the input data changes slightly (for example, a 1 becomes a 0), a completely different result will be obtained, and the result cannot be predicted in advance. Forward calculation (calculating the corresponding Hash value from the data) is very easy. Reverse calculation (cracking) is extremely difficult and is considered impossible under current technological conditions.
Core technology 3. Merkle tree:
Merkle tree is a hash binary tree, which can be used to quickly verify the integrity of large-scale data. In the blockchain network, the Merkle tree is used to summarize all transaction information in a block, and ultimately generates a unified hash value of all transaction information in the block. Any change in transaction information in the block will cause Merkle tree changes.
Core technology 4. Asymmetric encryption algorithm:
Asymmetric encryption algorithm is a key secret method that requires two keys: public key and private key. The public key and the private key are a pair. If the public key is used to encrypt data, only the corresponding private key can be used to decrypt it, thereby obtaining the corresponding data value; if the private key is used to sign the data, then only the corresponding public key can be used to sign the data. In order to verify the signature, the sender of the verification information is the holder of the private key.
Because encryption and decryption use two different keys, this algorithm is called an asymmetric encryption algorithm, while symmetric encryption uses the same key in the encryption and decryption processes.
Blockchain technology----network layer: realize the decentralization of accounting nodes
Core technology 5. P2P network:
P2P network (peer-to-peer network), also known as point-to-point technology, is no Central server, Internet system that relies on user groups to exchange information. Unlike a centralized network system with a central server, each client in a peer-to-peer network acts as both a node and a server. Domestic Xunlei software uses P2P technology. The P2P network has the characteristics of decentralization and robustness.
Blockchain technology----Consensus layer: allocate the task load of accounting nodes
Core technology 6. Consensus mechanism:
Consensus mechanism is how to reach consensus among all accounting nodes to identify The validity of a record is both a means of identification and a means of preventing tampering. There are currently four main types of consensus mechanisms: PoW, PoS, DPoS and distributed consensus algorithms.
PoW (Proof of Work, Proof of Work): PoW mechanism, which is like Bitcoin’s mining mechanism, miners package existing transactions that have not been recorded by the network into a block, and thenAfterwards, it will continue to traverse and try to find a random number, so that the hash value of the new block plus the random number meets certain difficulty conditions. Finding a random number that meets the conditions is equivalent to determining the latest block of the blockchain, and is also equivalent to obtaining the current round of accounting rights of the blockchain. Miners broadcast blocks that meet the mining difficulty conditions in the Yuanfu network. After verifying that the block meets the mining difficulty conditions and that the transaction data in the block meets the protocol specifications, other nodes in the entire network will each Blocks are linked to their own version of the blockchain, thereby forming a network-wide consensus on the current network state.
PoS (ProofofStake, Proof of Stake): PoS mechanism requires nodes to provide proof of a certain number of tokens to obtain a distributed consensus mechanism for competing for blockchain accounting rights. If you rely solely on the token balance to determine the bookkeeper, you will inevitably make the rich win, which will lead to the centralization of bookkeeping rights and reduce the fairness of the consensus. Therefore, different PoS mechanisms use different methods to increase the amount of money based on the proof of equity. The randomness of accounting rights avoids centralization. For example, in the PeerCoin PoS mechanism, the Bitcoin with the longest chain age has a greater chance of obtaining accounting rights. NXT and Blackcoin use a formula to predict the next accounting node. The more tokens you own, the greater the probability of being selected as an accounting node. In the future, Ethereum will also switch from the current PoW mechanism to a PoS mechanism. Judging from the information currently available, Ethereum's PoS mechanism will use nodes to place bets on the next block. The winner of the bet will receive an additional Ethereum currency award. Those who do not win will be deducted Ether coins to reach consensus on the next block.
DPoS (DelegatedProof-Of-Stake, share authorization certificate): DPoS is easy to understand and is similar to the modern corporate board of directors system. The DPoS mechanism adopted by BitShares is that shareholders vote to select a certain number of witnesses. Each witness has two seconds of authority to generate blocks in order. If the witness cannot generate a block within the given time slice, The block generation authority is given to the witness corresponding to the next time slice. Shareholders can replace these witnesses at any time by voting. This design of DPoS makes the generation of blocks faster and more energy-saving.
Distributed Consistency Algorithm: Distributed Consistency Algorithm is based on traditional distributed consistency technology. Among them are Byzantine fault-tolerant algorithms that solve the Byzantine Generals problem, such as PBFT (Byzantine fault-tolerant algorithm). In addition, distributed consensus algorithms (Pasox, Raft) that solve non-Byzantine problems are not explained in this article. This type of algorithm is currently a commonly used consensus mechanism in alliance chain and private chain scenarios.
Taken together, POW is suitable for public chains. If you build a private chain, it is more suitable to use POS because there is no trust problem in verification nodes; and because there are untrustworthy local nodes in the alliance chain, it is more suitable to use DPOS.
Blockchain Technology----Incentive Layer: Developing a "Salary System" for Accounting Nodes
Core TechnologyTechnique 7. Issuance mechanism and incentive mechanism:
Take Bitcoin as an example. Bitcoins are initially rewarded by the system to miners who create new blocks, and this reward is halved approximately every four years. At the beginning, miners were rewarded with 50 Bitcoins for each new block recorded, and this reward is halved approximately every four years. By analogy, by around AD 2140, newly created blocks will no longer receive rewards from the system. By then, the total number of Bitcoins will be approximately 21 million. This is the total number of Bitcoins, so it will not increase indefinitely.
Another source of incentives is transaction fees. When there are no system rewards for newly created blocks, the miners' income will change from system rewards to transaction fees. For example, when you transfer, you can specify 1% of it as a handling fee to be paid to the miner who records the block. If the output value of a transaction is less than the input value, the difference is the transaction fee, which will be added to the incentive for that block. As long as a given amount of electronic currency has entered circulation, the incentive mechanism can gradually be converted to rely entirely on transaction fees, so there is no need to issue new currency.
Blockchain technology----Contract layer: giving the ledger programmable features
Core technology 8. Smart contract:
Smart contract is a set of programmed rules and logic that respond to scenarios. Implemented by decentralized, trusted shared script code deployed on the blockchain. Normally, after the smart contract is signed by all parties, it is attached to the blockchain data in the form of program code, and is recorded in a specific block of the blockchain after being propagated through the P2P network and verified by nodes. Smart contracts encapsulate a number of predefined states and transition rules, scenarios that trigger contract execution, response actions under specific scenarios, etc. The blockchain can monitor the status of smart contracts in real time, and activate and execute the contract by checking external data sources and confirming that specific trigger conditions are met.
The above is what blockchain technologies the editor has brought to you? All content introduced to the core technology of blockchain.