区块链总结语,区块链总结报告

区块链是一种分布式的数据库技术，它可以用来存储和管理数据，并且可以通过计算机网络实现安全的数据交换。它具有去中心化、可验证性、不可篡改性、可追溯性、可扩展性等特点，可以用来解决各种安全性、可信度问题。本文将介绍区块链三个关键词：去中心化、可验证性和可追溯性。

去中心化是区块链的一个核心特性，它指的是没有中央机构或者第三方参与的情况下，用户之间可以安全地进行数据交换和交易。去中心化的特点使得区块链技术具有更高的安全性，因为没有中央机构可以控制或者改变数据，用户之间的交易也不需要第三方的监督和确认。去中心化的特点也使得区块链技术可以很好地解决传统中央机构的不可靠性、控制性和安全性问题。

可验证性是区块链技术的另一个重要特性，它指的是用户可以通过计算机网络来验证数据的真实性和有效性。区块链技术采用分布式账本技术，每个节点都可以拥有一份完整的账本，可以验证数据的有效性，用户可以根据账本来验证数据的真实性。可验证性的特点使得区块链技术具有更高的安全性，可以有效地防止数据被篡改或者窃取。

可追溯性是区块链技术的另一个重要特性，它指的是用户可以通过计算机网络追踪数据的流转情况。区块链技术采用分布式账本技术，每一笔交易都会被记录到账本中，每个节点都可以拥有一份完整的账本，用户可以根据账本来追踪数据的流转情况。可追溯性的特点使得区块链技术可以有效地解决传统的不透明性和可信度问题，使得用户可以更加安全地进行数据交换和交易。

以上就是区块链最重要的三个关键词：去中心化、可验证性和可追溯性，它们是区块链技术的核心特性，也是它可以解决安全性、可信度问题的关键所在。未来，区块链技术将会发挥更大的作用，成为一种新型的数据存储和交换技术。

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㈠ One article to understand the Internet blockchain

One article to understand the Internet blockchain

One article to understand the Internet blockchain, you need to understand the blocks In order to understand the blockchain, we have to study the brief history of the technological development of the blockchain starting from the birth of the Internet, discover the motivations for the emergence of the blockchain, and infer the future of the blockchain. Let’s understand the Internet blockchain in one article.

Understand the Internet blockchain in one article 1

The originator of blockchain is mahjong, and the earliest blockchain was invented by the Chinese! The blockchain is just like Mahjong, except that Mahjong has fewer blocks. Mahjong only has 136 blocks. The rules of Mahjong vary from place to place and can be regarded as a hard fork of Bitcoin.

As the oldest blockchain project, Mahjong has a team of four miners. The first one to dig out the 13 correct hash values ​​will get the accounting rights and rewards. It adopts the method of being willing to admit defeat and not cheating. Thousands of consensus mechanisms!

Mahjong is decentralized, everyone can be the banker, and it is completely peer-to-peer.

Mining pool = commission from the boss of the chess and card room.

It cannot be tampered with, because convincing the other three people requires too much computing power and physical strength.

A typical value Internet. The value in my pocket didn't last eight rounds before it went into their pockets.

The Chinese are basically good at playing mahjong. In terms of blockchain, they produce 70% to 80% of the world’s mining machines and have the most computing power in the world, accounting for about 77% of the computing power.

Mahjong is actually the earliest blockchain project:

1. A group of four miners. The miner who first collides with the correct hash value of 13 numbers can obtain the accounting rights. and get rewarded.

2. It cannot be tampered with. Because convincing the other three people requires too much computing power and physical strength.

3. Typical value Internet. The valuable digital currency www.gendan5.com/digitalcurrency/btc.html in my pocket ran into their pockets after eight rounds.

4. Decentralization, everyone can be a banker, it is completely peer-to-peer.

5. UTXO, unspent transaction expenses.

There is another blockchain method of credit, assuming that everyone has no cash

Let’s take a closer look. When everyone reaches a consensus, we see There is no intermediary or third party to judge C’s win, and the rewards given to C do not need to be transferred to C through a third party. They are all direct peer-to-peer transactions. This process is decentralized, and players (miners) record their own records. After recording the results of the first game, B Dahu drew thirteen pieces, and B drew Jia Dongfeng. After the record is completed, a complete block is generated, but remember, this is only the first game. In the entire blockchain On, this is just a node. After the 8 rounds mentioned at the beginning, that isIt is 8 nodes (blocks), and the 8 blocks are connected together to form a complete ledger, which is the blockchain. Because everyone has one of this ledger, it is a distributed ledger. The purpose is to prevent someone from tampering with the record. At the end of the game, it is clear who wins and who loses.

Four men (A, B, C, and D) got together to play mahjong for money. None of them brought any cash, so they asked a beautiful woman (centralized) to keep a book and record who won how much money in each round. , Who lost how much? At the end of the day, everyone uses Alipay or WeChat to pay and settle the ledger. However, if this beauty made a mistake in accounting or was bribed by one of the four people in advance to make a mistake on purpose, there is no guarantee that the outcome of this game will be fair, just, and reasonable. ,dont you agree? then what should we do? If you "play mahjong", you can use "blockchain" as the game rules and adapt it as follows:

Four men (A, B, C and D) got together to play mahjong for money. No one brought any cash. B said Let the beauty she brought keep accounts. A said that none of us knew this beauty, so the four of them, A, B, C, and D, agreed that everyone would keep accounts at the same time (decentralized) on their mobile phones (blockchain nodes) for each game. ), after finally playing mahjong and paying with electronic money directly on the mobile phone, everyone checked the accounting results. The accounting results should have been the same.

Assume that the original result is the account recorded on A’s mobile phone: B owes A 10 yuan. However, the record on B's mobile phone shows that there is no debt, but the other two people (C and D) have the same accounting as A, so the settlement is still based on the majority rule. In addition, everyone has a bad impression of B's ​​integrity. Next The first time I play mahjong, I won’t take B to play with me.

Unless B bribes two people (C and D) in advance to deliberately cheat, but the cost of B bribes them is 100,000 yuan (10,000 times the default of 10 yuan), then in common sense, B only You can choose to give up because the cost of counterfeiting is too high.

Assume that even if B is secretly willing to pay a high price of 100,000 yuan to buy C and D to do this silly cat transaction with huge losses during the card game, the rules of the blockchain are to keep accounts based on timestamps. Yes, it turns out that B owed A 10 yuan when debiting the account at 1 p.m., that is, when C and D changed the account at 3 p.m., time is irreversible and they can only record 3 p.m., which does not comply with the rules of the game. .

In fact, in 2017 the blogger has developed a set of Mahjong coins

China’s earliest blockchain project: a group of four miners, first starting from 148 random numbers The miner who collides with the correct hash value of 14 numbers can obtain an accounting right incentive. Since distributed accounting requires the consensus of several other miners, each accounting transaction takes about ten minutes.

Understanding the Internet Blockchain in One Article 2

1. Before the birth of Bitcoin, 5 Internet technologies that will have a significant impact on the future of the blockchain

In 1969, the Internet was born in the United States. Since then, the Internet has expanded from four research institutions in the United States to the entire planet. In terms of application, from the earliest military andScientific research extends to all aspects of human life. In the nearly 50 years since the birth of the Internet, five technologies have been of particularly great significance to the future development of blockchain.

1. The TCP/IP protocol born in 1974: determines the position of blockchain in the Internet technology ecosystem

In 1974, the most critical step in the development of the Internet was taken by The TCP/IP protocol, the core communication technology of the Internet jointly developed by American scientists Vinton Cerf and Robert Kahn, was officially launched.

This protocol enables the transmission of information between different computers and even different types of networks. All computers connected to the network can communicate and interact as long as they comply with this protocol.

In layman's terms, Internet data can travel tens of thousands of kilometers to reach the computer users who need it. This is mainly because the Internet world has formed a unified information dissemination mechanism. That is to say, Internet devices follow a unified law-TCP/IP protocol when disseminating information.

Understanding the TCP/IP protocol is of great significance to mastering the Internet and blockchain. After the invention of TCP/IP in 1974, the entire Internet was between the underlying hardware devices, the intermediate network protocols and the network Addresses have always been relatively stable, but an endless stream of innovative applications are emerging at the top application layer, including news, e-commerce, social networks, QQ, WeChat, and blockchain technology.

In other words, in the technical ecology of the Internet, blockchain is a new technology at the top layer of the Internet - the application layer. Its emergence, operation and development have not affected the underlying infrastructure and communication protocols of the Internet. , is still one of the many software technologies that operates according to the TCP/IP protocol.

2. Cisco router technology born in 1984: an imitation of blockchain technology

In December 1984, Cisco was established in the United States. The founder was a professor from Stanford University. A couple, Leonard Posak, director of the computer center, and Sandy Lerner, director of the business school's computer center, designed a networking device called a "multiprotocol router" that was placed on the Internet's communication lines to help data Get from one end of the Internet to the other thousands of kilometers away accurately and quickly.

In the entire Internet hardware layer, tens of millions of routers are busy working, directing the transmission of Internet information. An important function of Cisco routers is that each router saves a complete Internet device address table. Once something happens Changes will be synchronized to tens of millions of other routers (theoretically), ensuring that each router can calculate the shortest and fastest path.

When you see the operation process of the router, you will feel very familiar. That is the important feature of the blockchain later. The significance of understanding the router lies in the important features of the blockchain. It has been implemented on the router in 1984. For the router, even if the node device is damaged or attacked by hackers,, and will not affect the transmission of information on the entire Internet.

3. The B/S (C/S) architecture that was born with the World Wide Web: the opponent of the blockchain and the target of attempted subversion

The World Wide Web is referred to as the Web and is divided into Web clients and server. All updated information is only modified on the Web server. Thousands, tens of thousands, or even tens of millions of other client computers do not retain the information and only obtain the information data when accessing the server. This structure is often called the Internet B/S architecture is a centralized architecture. This architecture is also the most important architecture of the current Internet. Internet giants such as Google, Facebook, Tencent, Alibaba, and Amazon have all adopted this architecture.

Understanding the B/S architecture will be of great significance to the subsequent understanding of blockchain technology. The B/S architecture is that data is only stored in the central server, and all other computers obtain information from the server. Blockchain technology has tens of millions of computers without a center, and all data will be synchronized to all computers. This is the core of blockchain technology.

4. Peer-to-Peer Network (P2P): Blockchain The father of the chain and its technical basis

Peer-to-peer network P2P is another Internet infrastructure corresponding to C/S (B/S). Its characteristic is that multiple computers connected to each other are connected to each other. In a peer-to-peer position, there is no distinction between master and slave. A computer can be used as a server, setting shared resources for use by other computers in the network, and as a workstation.

Napster is one of the earliest P2P systems, mainly used for music resource sharing. Napster cannot be regarded as a true peer-to-peer network system. On March 14, 2000, a message was posted on the Slashdot mailing list of the underground hacker site in the United States, saying that AOL's Nullsoft department had released Gnutella, an open source Napster clone software.

In the Gnutella distributed peer-to-peer network model, each networked computer is functionally peer, serving as both a client and a server, so Gnutella is called the first true peer-to-peer network model. Network Architecture.

In the past 20 years, some Internet technology giants such as Microsoft and IBM, as well as liberals, hackers, and even criminals who infringe intellectual property rights, have continued to promote the development of peer-to-peer networks. Of course, those on the Internet want to strengthen information sharing. The idealists also put a lot of enthusiasm into peer-to-peer networks. Blockchain is a software application based on a peer-to-peer network architecture. It is a benchmark application for peer-to-peer networks trying to break out from the silence of the past.

5. Hash algorithm: the key to generating Bitcoin and tokens (tokens)

The hash algorithm converts numbers of any length into fixed-length values ​​using a hash function. Algorithms, famous hash functions such as: MD4, MD5, SHS, etc. It is established by the American National Institute of Standards and TechnologyA member of the defined family of cryptographic functions.

This family of algorithms is crucial to the functioning of the entire world. From Internet application stores, emails, anti-virus software, to browsers, etc., all of them are using secure hashing algorithms. It can determine whether Internet users have downloaded what they want, and it can also determine whether Internet users are involved in man-in-the-middle attacks or network attacks. Victim of a phishing attack.

The process of blockchain and its application to generate new coins from Bitcoin or other virtual currencies is to use the function of the hash algorithm to perform operations to obtain numbers that meet the format requirements, and then the blockchain program gives Bitcoin rewards.

Mining, including Bitcoin and tokens, is actually a small mathematical game built with a hash algorithm. However, because of the fierce competition, people all over the world used powerful servers to perform calculations in order to get the rewards first. As a result, many computers on the Internet participated in this little mathematical game, which even consumed more than 40% of the electricity in some countries.

2. The birth and technical core of blockchain

The birth of blockchain should be the most unusual and mysterious invention and technology in the history of human science, because apart from blockchain, So far, there is no major invention in the history of modern science whose inventor cannot be found.

On October 31, 2008, Bitcoin founder Satoshi Nakamoto (pseudonym) published a paper on the cryptography mailing group - "Bitcoin: A Peer-to-Peer Electronic Cash System". In this paper, the author claims to have invented a new electronic currency system that is not controlled by governments or institutions. Blockchain technology is the basis for supporting the operation of Bitcoin.

The preprint address of the paper is at http://www.bitcoin.org/bitcoin.pdf. From an academic point of view, this paper is far from a qualified paper. The main body of the article is composed of 8 flow charts. It is composed of corresponding explanatory text, no nouns and terms are defined, and the format of the paper is also very irregular.

In January 2009, Satoshi Nakamoto released an application case of blockchain on the SourceForge website - the open source software of the Bitcoin system. After the release of the open source software, it is said that Satoshi Nakamoto mined approximately 1 million bits. Coin. A week later, Satoshi Nakamoto sent 10 Bitcoins to cryptography expert Hal Finney, which became the first transaction in Bitcoin history. With the booming development of Bitcoin, research on blockchain technology has also begun to show explosive growth.

It is indeed difficult to explain the blockchain to the public completely and clearly. We use Bitcoin as the object to introduce the technical characteristics of the blockchain as simply as possible but in depth.

1. Blockchain is a peer-to-peer network (P2P) software application

As we mentioned before, at the beginning of the 21st century, the Internet formed two major types of applications. Architecture, centralized B/S architecture and non-centered peer-to-peer (P2P) architecture, Alibaba, Sina, AmazonXun, many Internet giants such as the Internet have a centralized B/S architecture. To put it simply, data is placed on giant servers. We ordinary users access the servers of Alibaba, Sina and other websites through mobile phones and personal computers.

Since the beginning of the 21st century, there have been many software applications for freely sharing music, videos, and paper materials. Most of them use a peer-to-peer network (P2P) architecture, that is, there is no central server, everyone's personal computer They are all servers and clients, with equal status. However, this type of application has never become popular. The main reasons are large resource consumption and intellectual copyright issues. Blockchain is a software application in this field.

2. Blockchain is a peer-to-peer network (P2P) software application that synchronizes information across the entire network

Peer-to-peer networks also have many application methods. In many cases, everyone is not required to Each computer keeps the same information. Everyone only stores the information they need, and downloads it to other computers when needed.

However, in order to support Bitcoin financial transactions, the blockchain requires that every transaction that occurs must be written into historical transaction records and change information be sent to all computers with Bitcoin programs installed. Every computer with Bitcoin software installed maintains the latest and complete Bitcoin historical transaction information.

The characteristics of blockchain's network-wide synchronization and network-wide backup are often referred to as blockchain information security, and the source cannot be changed. Although it is still not absolutely safe in practice, when the number of users is very large, it does have certain security advantages in preventing information tampering.

3. Blockchain is a peer-to-peer (P2P) software application that uses a hash algorithm to generate "tokens" to synchronize information across the entire network

Area The first application of blockchain is the famous Bitcoin. When discussing Bitcoin, a term that is often mentioned is "mining". So what exactly is mining?

The metaphor is that the blockchain program gives the miners (players) 256 coins, numbered 1, 2, 3...256. Each time a Hash operation is performed, it is like tossing a coin. 256 coins are thrown at the same time. After landing, if all the coins with the first 70 numbers happen to be heads. The miner can tell the blockchain program this number, and the blockchain will reward the miner with 50 Bitcoins.

From the perspective of software programs, Bitcoin mining is a mathematical game built using the hash SHA256 function. The blockchain first stipulates a winning mode in this small game: a 256-bit hash number is given, but the last 70 bits of the hash number are all 0, and then the player (miner) continuously enters various numbers. Give the hash SHA256 function and see if you can use this function to get a number with 70 zeros. If you find one, the blockchain program will reward the player with 50 Bitcoins. Actual mining and rewards are more complex, but the above example expresses the core process of mining and obtaining Bitcoin.Procedure.

When Bitcoin was born in 2009, each bounty was 50 Bitcoins. Ten minutes after its birth, the first batch of 50 Bitcoins was generated, and the total currency amount at this time was 50. Subsequently, Bitcoin increased at a rate of about 50 every 10 minutes. When the total amount reaches 10.5 million (50% of 21 million), the bounty is halved to 25. When the total amount reaches 15.75 million (new output is 5.25 million, which is 50% of 1050), the bounty is further halved to 12.5. According to the design of the Bitcoin program, the total number of Bitcoins is 21 million.

From the above introduction, Bitcoin can be seen as a guessing game based on a peer-to-peer network architecture. The Bitcoin information rewarded for each correct guess will be transmitted to all players and recorded. into each player's history database.

4. Smart contracts, tokens, ICOs and blockchain basic platforms generated by blockchain technology due to the rise of Bitcoin

From the above introduction, Bitcoin technology It is not a new technology falling from the sky, but a clever combination of various original Internet technologies, such as peer-to-peer network architecture, network-wide synchronization of routing, and network security encryption technology. It can be regarded as a combination of innovative algorithm games. .

Because Bitcoin can be exchanged for legal currency, purchased in kind, and made huge profits through appreciation, the whole world is not calm. With the attitude that if you can do it, I can do it, many people have created their own imitation Bitcoin software applications. At the same time, taking advantage of the difficulty for the government to regulate peer-to-peer networks, various altcoins exploded together with Bitcoin. There have been many incidents of fraud and absconding, which have gradually attracted the attention of governments around the world.

Blockchain basic platform: It is still quite technically difficult to create currency using the blockchain technology framework. At this time, basic technology platforms such as Ethereum, the blockchain basic platform, have emerged, making it convenient for ordinary people. Create a "Bitcoin"-like software program, each showing its magical powers, inviting people to join the game to mine coins, speculate on coins, and gain profits from it.

Pass or token: If each "Bitcoin" or "Altcoin" uses a hash algorithm to create a guessing game and generates its own "currency", this "currency" is collectively referred to as " "Certificate" or "Token".

ICO: Since Bitcoin and Ethereum have been exchanged with the legal currencies of various countries, when other new virtual currencies are issued, only Bitcoin and Ethereum are allowed to purchase the new issued coins. Such a currency issuance process It’s called ICO. The emergence of ICO has amplified the transaction volume of Bitcoin and Ethereum. At the same time, many ICO projects are completely based on nihilistic projects, resulting in a large number of frequent fraud cases. This further deepens society’s negative understanding of virtual currencies generated by blockchain.

Smart contract: It can be seen as a software function on the blockchain. It is a program that assists various virtual currency transactions on the blockchain. The specific function is like the fund custody of Alipay on Taobao. When a user receives the goods and confirms them on Alipay, the funds are automatically paid to the buyer and owner., smart contracts also assume this intermediary payment function in blockchain applications such as Bitcoin.

3. The historical status and future prospects of blockchain technology in the Internet

1. Where does blockchain stand in Internet technology? It is a new software and architecture at the top level.

We mentioned in the previous introduction to TCP/IP that blockchain, like browsers, QQ, WeChat, online game software, mobile APPs, etc., is a software form of the top layer of the Internet - the application layer. . Its operation still relies on the TCP/IP architecture system to transmit data. But unlike most application layer software, it does not adopt the central software architecture of C/S (B/S). Instead, an unusual peer-to-peer network architecture is adopted. From this point of view, blockchain cannot subvert the Internet infrastructure.

2. Who does blockchain want to subvert? Want to subvert the B/S (C/S) structure of the World Wide Web.

It attempts to subvert the B/S, C/S structure of the World Wide Web, which was born in 1989. Said before. Since 1989, European physicist Tim Berners-Lee invented the World Wide Web and gave up applying for a patent. In the past nearly 30 years, companies including Google, Amazon, Facebook, Alibaba, Internet, Tencent and other companies have used the B/S (C/S) structure of the World Wide Web to grow into Internet giants.

In their headquarters, a powerful central server cluster was established to store massive amounts of data. Hundreds of millions of users obtained the data they needed from the giant servers. This also led to the emergence of cloud computing, and then the Internet giants Open up your unused central server resources to further absorb data from enterprises, governments, and individuals. Centralized Internet giants have an increasing influence on the world, countries, and Internet users.

The goal of blockchain is to try to reduce the influence of Internet giants by distributing data to each Internet user’s computer. It can be seen that the real opponent of blockchain and what it wants to subvert is the 1990 The B/S (C/S) structure born in 2007. But whether it can be subverted depends on its technical advantages and bottlenecks.

3. Technical flaws of blockchain: dilemmas caused by the pursuit of complete equality and freedom

The technical flaws of blockchain first come from its peer-to-peer network architecture. For example For example, Taobao currently has a B/S structure, and massive data is stored in the Taobao server cluster computer room. Hundreds of millions of consumers access the Taobao server website through their browsers to obtain the latest information and historical information.

If blockchain technology is used, hundreds of millions of people will retain a complete Taobao database on their personal computers or mobile phones. Every time a transaction occurs, it will be synchronized to hundreds of millions of other users. This is completely unachievable in reality. The amount of data transferred and stored is too large. It is equivalent to setting up and running hundreds of millions of Taobao websites at the same time.

Therefore, blockchain cannot be applied to projects with large amounts of data, and even smaller website projects cannot use blockchain.It will be difficult. By 2018, Bitcoin had been running for nearly 10 years, and the accumulated transaction data had brought the entire system to collapse.

So the blockchain has adopted many alternative methods, such as establishing relay nodes and lightning nodes. These two concepts can also make people confused. In layman's terms, the blockchain will ask it for The subversive object B/S structure has been studied, and a data server center has been established to become the relay node of the blockchain, which can also be accessed with a browser-like terminal. This is the lightning node of the blockchain.

This change can alleviate the technical shortcomings of the blockchain, but it does make the blockchain what it opposes, centralization. It can be seen that pure blockchain technology has major flaws due to its technical characteristics and cannot be widely used like the World Wide Web. If the technology is upgraded and some parts adopt a B/S (C/S) structure, the blockchain will become centralized. The information node no longer maintains the dream when it was born.

4. Looking at the future prospects of blockchain from the Internet brain model

We know that the Internet generally refers to the Internet that connects computer networks around the world. On this basis The development of a global Internet network covering the whole world is called the Internet, which is a network structure that is interconnected.

Since the birth of the Internet in 1969, humans have innovated in the Internet field from different directions, and there is no unified plan to build the Internet into a structure. When the wheel of time reaches 2017, with the advent of artificial intelligence, With the vigorous development of science and technology such as the Internet of Things, big data, cloud computing, robots, virtual reality, and the industrial Internet, when humans look up to see the giant systems they have created, the model and architecture of the Internet brain have become increasingly clear.

Through nearly 20 years of development, relying on the B/S and C/S structures of the World Wide Web, Tencent QQ, WeChat, Facebook, Weibo, and Twitter Amazon have developed structures similar to neuron networks. Internet devices, especially personal computers and mobile phones, map personal data and functional space on the giant's central server through the software on the device, allowing them to add friends, communicate and transfer information. Internet giants continue to optimize the software versions of hundreds of millions of terminals through software upgrades in central server clusters. In the neurological system, this is a standard central nervous system structure.

The birth of the blockchain provides another neuron model. Instead of uniformly managing neurons in the centralized services of giants, each terminal, including personal computers and personal mobile phones, becomes an independent neuron node. , retaining an independent data space and synchronizing mutual information. In the neurological system, this is a distributed neural structure with no center and multiple neural nodes.

Interestingly, these two different types of neural structures appear in the development of the nervous system. In lower organisms, blockchain-like neural structures have appeared, with multiple ganglia with the same functions, all of which can command body activities and reactions. However, with the evolution of organisms, these ganglia gradually merged.When we evolved into higher organisms, the central nervous system appeared, which contains a large number of neurons for interaction.

4. Judgment on the future status of blockchain in the Internet

1. Understanding of Bitcoin: a guessing game based on peer-to-peer network architecture (P2P), Through clever financial and public opinion operations, it has become a "world currency" that is not subject to government supervision.

2. Understanding of blockchain: a peer-to-peer (P2P) software application that uses a hash algorithm to generate "tokens" to synchronize information across the entire network.

3. Blockchain has specific uses, such as large-scale election voting, large-scale gambling, financial transactions that circumvent government financial supervision, etc. It still has irreplaceable uses.

4. In more cases, blockchain technology will rely on the B/S and C/S structures of the Internet to achieve functional expansion, but overall it is still a supplement to the existing technology of the Internet. Most of the application scenarios currently envisaged by blockchain can be implemented using B/S and C/S structures, with higher efficiency and more mature technology.

5. Whether from the perspective of information transmission efficiency and resource consumption, or from the evolution of the nervous system, blockchain cannot become the mainstream architecture of the Internet, let alone a subversive and revolutionary leader of the future Internet.

6. Of course, Internet giants developed with B/S and C/S structures also have their problems, but these can be gradually solved through commercial and political methods in the future.

㈡ Summary of general concepts of blockchain

Although I am a front-end developer, it cannot stop me from gossiping about various hot topics. Below is a brief summary of some of the conceptual things learned.

1. Blockchain technology was born with Bitcoin, so first understand the concept of Bitcoin

2. What is Bitcoin

(1) , Digital currency based on distributed network

3. Operating principle of the bit system

(1) All nodes will save complete ledgers

(2 ), the ledger maintains consistency

4. Blockchain accounting principles

Hash functions are widely used in blockchain technology

(1), Hash function hash: any information will get a short summary information after hashing

(2), hash characteristics: simplified information, identification information, hidden information, verification information

(3) Blockchain accounting will hash the bill information of the time node to form a block

(4) The Bitcoin system will record accounting once every 10 minutes, that is, every block generation timeThe interval is about 10 minutes

(5) When recording the next bill, the hash value of the previous block and the current bill information will be hashed together as the original information

(6). Each block contains the information of the previous blocks, and these blocks are combined to form a blockchain

5. Bitcoin ownership-asymmetric encryption application
< br />The Bitcoin system uses an elliptic curve signature algorithm. The private key of the algorithm consists of a 32-byte random number. The public key can be calculated through the private key. The public key undergoes a sequence of hash algorithms and encoding algorithms to obtain the Bitcoin address. , the address can also be understood as the digest of the public key.

(1). Transfer is to transfer Bitcoin from one address to another

(2). The address private key is an asymmetric relationship. The private key passes through a series of (including two hashes), you can get the address, but the private key cannot be obtained from the address

(3) After the transfer is successful, it is broadcast to other nodes, and other nodes forward it to the relevant node after successful verification. Neighboring nodes, the broadcast information contains the original information and signature information

(4) Verification, other nodes verify whether the signature information is generated by the payer using the private key to sign the original transaction information. If It is recorded (then verify that there is sufficient balance)

6. How to mine Bitcoin

(1) Nodes that complete accounting can obtain a certain number of bits given by the system Coin rewards (this reward process is also the issuance process of Bitcoin, so everyone calls bookkeeping mining)

(2) Only one person can successfully bookkeeping within a period of time, so it is necessary to collect Collect the original transaction information, check whether there is a balance and correct signature

(3) In order to improve the difficulty of accounting, only one person can do accounting in about ten minutes. The hash result needs to start with several 0s, and Introduce random number variables when hashing

(4) As more miners join, the game becomes more and more difficult, the calculation difficulty increases, and the power loss increases. Domestic electricity costs are low, and China The computing power accounts for more than half of the entire network

(5). Only the fastest decrypted block in the network will be added to the ledger, and other nodes will copy it to ensure the uniqueness of the ledger. If a node cheats and causes the entire network to fail, it will be discarded and never recorded in the general ledger. Therefore all nodes will abide by the common protocol of the Bitcoin system.

[Thinking about which fields blockchain will extend to]:

From the above concepts, it can be concluded that blockchain technology has such security and uniqueness, decentralization.

In principle, some information leakage can be avoided, allowing the confirming party to confirm your identity without exposing your real user information.

At present, blockchain technology is mainly used in Bitcoin. I think the greater significance in the future should be in areas that require data privacy and security.

[Thinking about the bottlenecks and limitations of the current development of blockchain]:

Since each node participates in the entire ledger recording activity, it will inevitably cause waste and loss of resources. . As well as increasing the computational difficulty of each node, subsequent development and popularization require hardware improvements for each node.

㈢ Lesson 4 Cryptography Learning Summary in Blockchain

This is the fourth lesson of deep learning in Ulord. Dr. Yang will give a lecture on cryptography in blockchain. Question, this course helped me understand a question about public keys and private keys that has been bothering me. What is the relationship between them? I got the answer in this study, and now I will share with you what I learned.

The public key and private key in the blockchain are two basic concepts in asymmetric encryption.

Public key and private key are a key pair obtained through an algorithm. The public key is the public part of the key pair, and the private key is the non-public part. Public keys are usually used to encrypt conversations, that is, messages or information, and can also be used to verify digital signatures signed with private keys.

The private key can be used to sign and the corresponding public key can be used for verification. The key pair obtained through this public key system can be guaranteed to be unique worldwide. When using this key pair, if you use one of the keys to encrypt data, you must use its corresponding other key to decrypt it.

For example, data encrypted with a public key must be decrypted with a private key. If a private key is used for encryption, the corresponding public key must be used to decrypt it, otherwise the decryption cannot be successful. In addition, in the Bitcoin blockchain, the public key is calculated through the private key, and the address is calculated through the public key, and this process is irreversible.

㈣ Blockchain technology and applications: a technological revolution in the future

Blockchain technology originated from "Bitcoin: A Peer-to-Peer Electronic Cash System" proposed by Satoshi Nakamoto 》, where "block" means that each information block contains a timestamp. Information blocks containing timestamps are connected to each other, and the chain of information blocks formed is a "blockchain".

Blockchain is a technical solution that collectively maintains a reliable database in a decentralized and trustless manner. From a data perspective, blockchain is a distributed database in which a single node or multiple nodes cannot intentionally change data records. Its distribution is reflected in the distributed storage and distributed recording of data.record. From a technical perspective, blockchain technology is an emerging technological achievement resulting from the integration of multiple technologies. After the development and improvement of a combination of multiple technologies, it forms a more efficient way of recording, storing and expressing data.

"Science China" is an authoritative scientific brand of the China Association for Science and Technology, which collaborates with all parties in society to use information technology to spread science.

This article is produced by Popular Science China Fusion Creation. Please indicate the source when reprinting.

㈤ A brief discussion of several major applications of blockchain and which ones are pitfalls

What can blockchain do? Blockchain, a great technology that accompanied the birth of Bitcoin, is currently being used in the financial field to significantly reduce transaction costs and improve efficiency, which is enough to excite Wall Street. However, this is just the tip of the iceberg. Its potential applications are very broad and will subvert every aspect of our lives in the future.

The Internet is an information network, with 0s and 1s flowing in it. Blockchain is a value network, and its role is to transmit value, unlike the Internet for data transmission.

Speaking of value transfer, there is a very simple scenario, such as payment, I have 100 yuan in hand, and I want to transfer it to the group. I can use WeChat red envelopes or WeChat transfers. Here During the transaction process, a third party is required to participate, and the transmission method of the blockchain is point-to-point transmission, which does not require any intermediate node. This is a very big difference between the blockchain and our existing architecture.

When it comes to peer-to-peer payments, many people will think of Bitcoin, because most people know blockchain from Bitcoin. What is the difference between blockchain and Bitcoin?

Blockchain is the technology behind Bitcoin; blockchain is a basic technical architecture that designs and implements an autonomous system with multi-party participation through a specific data structure and consensus algorithm.

The specific data structure is actually the name blockchain itself, that is, its data is placed in data blocks one by one, and then these data blocks are connected and implemented using a chain. "Consensus algorithm" is a very important concept in blockchain. Without synchronic algorithm, there would be no meaning of blockchain.

Introduction to Bubi Blockchain

Bubi Blockchain has been focusing on the R&D and innovation of blockchain technology and products since its establishment, and has a number of core technologies. It has made substantial innovations in many aspects and formed a number of core technical achievements, such as: mathematically provable distributed consensus technology, fast large-scale ledger access technology, multi-chain general ledger technology that supports business expansion, and heterogeneous ledger technology. Construct interconnection technology between blockchains, etc. On April 25, "Gege Points" introduced the concept of blockchain into the points system, jointly opened it up with multiple parties, issued and redeemed points, and promoted the circulation of points. Each cooperative institution can jointly participate in transaction verification, ledger storage, and real-time settlement; it is a third-party payment platform for corporate points issuers.Make points entry and exit more flexible. Bubi has developed its own basic blockchain service platform, which has been applied in equity, supply chain, points, credit and other fields. Bubi has been committed to building an open value circulation network with decentralized trust as the core, allowing digital assets to flow freely.

Having said that, let’s analyze the difference between blockchain and Bitcoin?

1. Essential difference. For the world, Bitcoin is a digital currency based on cryptography, while blockchain, as we just said, is a value transfer protocol. There is an essential difference between the two, because one is a digital currency. , one is a value transfer protocol.

2. Algorithm. Bitcoin's consensus algorithm is based on a working algorithm called proof of work, POW. There are many different consensus algorithms in the blockchain. It can use either the Bitcoin POW algorithm, the POS algorithm, or the DPS algorithm.

3. Transaction speed. Bitcoin is limited to a maximum of seven transactions per second. Please note that what is mentioned here is the maximum and not the average, because this is a very strict definition. For the blockchain, the number of transactions per second can actually reach tens of thousands or more, so this is also One major difference between blockchain and Bitcoin. Because many people will be confused and say that the transaction speed of the blockchain is seven transactions per second. This is wrong. This is a limitation of Bitcoin. The blockchain can reach very high speeds based on its different consensus algorithms and linking methods. Transaction speed.

4. Link form. Bitcoin is a blockchain based on the Internet, which means we call it a public chain. The blockchain can be in the form of a public chain, a private chain, or a consortium chain.

5. Limitations. It is recommended that everyone not touch some digital currencies related to blockchain. What's the reason? Bitcoin is a digital currency. Although it has very good and different characteristics, it does not comply with financial supervision. In other words, these 21 million Bitcoins were issued without national authorization and without national credit as a multiple. was released below. The blockchain also has some limitations. Although it is just a protocol and a technology, it is still a new technology in its infancy.

To summarize, blockchain is a relatively low-level protocol and a technical infrastructure, on which there are various consensus algorithms. If the blockchain is 1, the consensus algorithm may be 10 to 20, but the applications based on it may be one thousand or two thousand, or more. In other words, Bitcoin is only one of many blockchain applications. A realization. Therefore, Bitcoin and blockchain cannot be equated. Bitcoin is only a very elementary implementation of blockchain.

What can blockchain do? Blockchain problem? In the bill market, digital currencies based on blockchain technologyBills can become safer, smarter and more convenient forms of bills. Point-to-point transactions realized with the help of blockchain can break the existing functions of bill intermediaries and realize the disintermediation of bill value transfer; the construction and data storage of digital bill systems do not require a central server, eliminating the need for the development of central applications and access systems. cost, which reduces the maintenance and optimization costs of the system under the traditional model, and reduces the risks caused by system centralization; based on the non-tamperability of information on the blockchain, once the transaction is completed, there will be no default, thereby avoiding "one Behaviors such as "selling too many tickets" and out-of-synchronization of payment and endorsement effectively prevent risks in the bill market. The securities trading market is also an area where blockchain technology has great potential. The current traditional securities trading model has the shortcomings of long transaction processes, low transaction efficiency, and high comprehensive costs. In addition, there are strong intermediaries and regulatory agencies, and the rights of financial consumers are often not protected. Applying blockchain technology, buyers and sellers can be directly matched through smart contracts, and the efficiency of transaction execution can be greatly improved. Settlement and delivery can be automatically realized through a distributed digital registration system. Since the data entered into the block is irreversible and can be copied to each data block within a short period of time, the information entered into the blockchain actually has a publicity effect, so the occurrence of the transaction and the confirmation of ownership will not occur. dispute.

What can blockchain do? Blockchain problem? Although there is no mature underlying blockchain technology platform solution currently, technical problems such as capacity scalability, privacy protection, inability to settle on a net basis, and non-recourse after the event also need to be solved, and large-scale application of blockchain Technology also requires redesigning IT architecture and reengineering business processes, but these are only technical issues. The real test of blockchain technology taking root and growing in the financial field is the ontology of regulatory agencies and financial institutions. Will the inherent "deregulation" and "decentralization" characteristics of blockchain make market entities have no motivation to drive technology? Innovation. However, since the blockchain is a technology based on mathematical algorithms, the establishment of a trust relationship between transaction parties does not require the use of intermediaries or authoritative centers at all, and the cost of establishing a trust relationship is almost zero (when the blockchain financial infrastructure and ancillary infrastructure are established (under the premise), and the blockchain code is open source and open, without geographical restrictions, and the network pattern is distributed and interconnected, laying a technical foundation for the establishment and development of inclusive finance and shared finance in the future, and creating material conditions for global financial integration and unification. From this point of view alone, blockchain technology will surely establish a core position in future financial development, and it will rely on and complement each other to win the future.

㈥ The future of blockchain is a major trend

Blockchain uses P2P technology, cryptography and consensus algorithms and other technologies, and has the characteristics of non-tamperable data, collective system maintenance, and open and transparent information. and other characteristics. Blockchain provides a mechanism for information and value transfer and exchange in an untrusted environment, and is the cornerstone of building the future value Internet.

Trend 1: The application of blockchain industry is accelerating, from digital currency to AfricanPenetration and diffusion in the financial field

As a universal technology, blockchain technology is accelerating its penetration from digital currency to other fields, and is integrating with innovations in all walks of life. We believe that future blockchain applications will be driven by two camps. On the one hand, the IT camp starts with information sharing and focuses on establishing credit at low cost, gradually covering areas such as digital assets. On the other hand, the cryptocurrency camp starts from currency and gradually advances to the fields of asset management and certificate depository, and spreads to credit reporting and general information sharing applications.

Trend 2: Enterprise application is the main battlefield of blockchain, and alliance chain/private chain will become the mainstream direction

At present, the actual application of enterprises is concentrated in the field of digital currency, which belongs to virtual economy. We believe that future blockchain applications will move from virtual reality to reality. More traditional enterprises will use blockchain technology to reduce costs, improve collaboration efficiency, and stimulate the growth of the real economy. This will be the main battlefield for blockchain applications in the future.

Unlike public chains, in enterprise-level applications, everyone pays more attention to factors such as blockchain control, regulatory compliance, performance, and security. Therefore, we believe that strong management blockchain deployment models such as alliance chains and private chains are more suitable for enterprises to use in application implementation, and are the mainstream technology direction for enterprise-level applications.

Trend 3: Applications have spawned diversified technical solutions, and blockchain performance will continue to be optimized

In the future, blockchain applications will develop from single to multiple directions. Different applications such as billing, payment, insurance, and supply chain will be highly differentiated in multiple dimensions such as real-time, high concurrency, latency, and throughput. This will lead to a diverse range of technological solutions. We believe that blockchain technology is far from finalized and will continue to evolve in the future. There is room for efficiency improvement in technical aspects such as consensus algorithms, service sharding, processing methods, and organizational forms.

Trend 4: Blockchain and cloud computing are increasingly integrated, and BaaS is expected to become a public trust infrastructure

Cloud computing is the general trend. We believe that the combination of blockchain and cloud is also an inevitable trend. There are two models for the combination of blockchain and cloud, one is blockchain on the cloud, and the other is blockchain in the cloud. The latter one, namely BaaS, Blockchain-as-a-Service, refers to the cloud service provider directly providing blockchain as a service to users. In the future, cloud service companies will increasingly integrate blockchain technology into the cloud computing ecological environment. By providing BaaS functions, they can effectively reduce the deployment cost of enterprise application blockchain and lower the initial threshold for innovation and entrepreneurship.

Trend 5: Blockchain security issues are becoming increasingly prominent, and security protection requires overall technical and management considerations

From a mathematical point of view, the blockchain system is almost perfect, with openness, transparency, It has the advantages of being difficult to tamper with, reliable encryption, and preventing DDoS attacks. However, from an engineering perspective, its security is still restricted by infrastructure, system design, operation management, privacy protection, and technology update iterations. In the future, we need to consider the overall situation in terms of technology and management, and strengthen basic research and overall protection to ensure application security.

Trend 6: The cross-chain demand for blockchain is increasing, and the importance of interconnection is highlighted

With the deepening of blockchain applications, payment and settlement, logistics traceability, medical records Enterprises or industries in areas such as identity verification and identity verification will establish their own blockchain systems. We believe that cross-chain collaboration and interoperability among these numerous blockchain systems is an inevitable trend in the future. It can be said that cross-chain technology is the key to blockchain realizing the Internet of Value, and the interconnection of blockchains will become an increasingly important issue.

Trend 7: Blockchain competition is becoming increasingly fierce, and patent competition has become an important area of ​​competition

As the number of participating entities increases, blockchain competition will become increasingly fierce. Competition is all-round, including technology, models, patents and other dimensions. We believe that in the future, companies will strengthen their layout in blockchain patents. Since 2014, the number of blockchain patent applications has exploded. Blockchain patents are mainly distributed in the United States in North America, the United Kingdom in Europe, and China and South Korea in Asia. This pattern will be maintained in the future. The patent gap between China and the United States is narrowing, and China’s number of applications in 2016 has surpassed that of the United States. It is foreseeable that the competition for blockchain patents will become increasingly fierce in the future.

Trend 8: Blockchain investment continues to be popular, and the cumulative risks of the token crowdfunding model deserve attention

Blockchain has become a hot spot pursued by the capital market. Future investment will continue the rising trend from 2014 to 2016. Different from financing models in other technology fields, a model called "token crowdfunding" has emerged in the blockchain field, namely Initial Coin Offering (ICO), which is a type of crowdfunding for startups to issue tokens and raise funds. Way. As the transaction volume of token crowdfunding increases, risks such as lack of review, huge value fluctuations, and being on the edge of regulation for many projects will increase, which deserves attention. This afternoon, a group of friends chatted with me privately and asked about the so-called golden chain, which needs to rely on the model of 1 pass 2, 2 pass 4, 4 pass 16 to obtain income. This is an obvious pyramid scheme to attract people, but there are still many people who just Friends who have entered the currency circle and have just learned about blockchain will be deceived. I hope they can understand the essence and be responsible for their own funds!

Trend 9: There is a conflict between blockchain technology and supervision, but the contradiction is expected to be further reconciled

The decentralization, disintermediation and anonymity of blockchain are incompatible with traditional enterprise management It is not coordinated with the government regulatory system. But we should also see the opportunities that blockchain brings to supervision. We believe that in the future, companies will actively cater to regulatory needs and proactively build in regulatory requirements in technical solutions and model designs. They will not only achieve compliant operations, but also significantly save the cost of regulatory compliance. We also believe that in the future, regulatory authorities around the world will also embrace blockchain, a new regulatory technology, and use new technology to improve government regulatory efficiency.

Trend 10: Trustworthiness is the core requirement of blockchain, and the importance of standards and specifications is becoming increasingly prominent

In the future value delivery network based on blockchain, We will use algorithms and software entirely to build a foundation of trust. But we believe that this is far from enough. Standards are also needed to add credibility to the blockchain. In the future, blockchain standards will start from the user's perspective and be business-oriented, standardizing the technology and governance of blockchain from the dimensions of smart contracts, consensus mechanisms, private key security, permission management, etc., and enhancing the efficiency of blockchain. The degree of credibility adds weight to the trust of the blockchain.

Summary

The above are the ten major trends summarized. To summarize, there are four points: First, blockchain is the foundation of the value network and has gradually become an indispensable part of the future Internet. Second, as application scenarios become increasingly abundant, applications will drive the continuous improvement of blockchain technology, and the integration of blockchain and cloud will become increasingly closer. Third, although the blockchain is mathematically complete, there are also security issues. In the future, security needs to be strengthened from the engineering and management levels, and standards are also needed to improve credibility. Fourth, blockchain technology will gradually adapt to regulatory policy requirements in the future and gradually become an important tool for regulatory technology.

㈦ Tutorial for getting started with blockchain

However, there are very few simple and easy-to-understand introductory articles. What exactly blockchain is and what makes it special is rarely explained.
Next, I will try to write a best-understood blockchain tutorial. After all, it is not difficult. The core concept is very simple and can be explained clearly in a few sentences. I hope that after reading this article, you will not only understand the blockchain, but also understand what mining is, why mining is getting more and more difficult, and other issues.
It should be noted that I am not an expert in this area. Although I have been paying attention to it for a long time, my detailed understanding of blockchain started at the beginning of this year. You are welcome to correct any errors or inaccuracies in the article.
1. The essence of blockchain
What is blockchain? In a word, it is a special distributed database.
First of all, the main function of blockchain is to store information. Any information that needs to be saved can be written to the blockchain and read from it, so it is a database.
Secondly, anyone can set up a server, join the blockchain network, and become a node. In the world of blockchain, there is no central node. Every node is equal and stores the entire database. You can write/read data to any node, because all nodes will eventually be synchronized to ensure that the blockchain is consistent.
2. The biggest features of blockchain
Distributed databases are not a new invention, and there have been such products on the market for a long time. However, blockchain has a revolutionary feature.
Blockchain has no administrator, it is completely centerless. Other databases have administrators, but blockchain does not. If one wanted to add auditing to the blockchain, it would not be possible because it is designed to prevent the emergence of a central authority.
It is precisely because it is unmanageable that blockchain can be uncontrollable. Otherwise, once big companies and large groups control the management, they will control the entire platform, and other users will have to take orders from them.
However, without the administrator, everyone can write data into it. How can we ensure that the data is trustworthy? What should I do if it is modified by bad people? Please read on, this is the wonderful thing about blockchain place.
3. Block
Blockchain is composed of blocks. Blocks are much like database records. Every time data is written, a block is created.
Each block contains two parts.
Head: records the characteristic values ​​of the current block
Body: actual data
The block header contains multiple characteristic values ​​of the current block.
Generation time
Hash of the actual data (i.e. block body)
Hash of the previous block
...
Here, you need to understand what a hash is , which is necessary to understand blockchain.
The so-called hashing means that the computer can calculate a characteristic value of the same length for any content. The hash length of the blockchain is 256 bits, which means that no matter what the original content is, a 256-bit binary number will be calculated in the end. And it can be guaranteed that as long as the original content is different, the corresponding hash must be different.
For example, the hash of the string 123 is (hexadecimal), which is 256 bits when converted to binary, and only 123 can get this hash. (Theoretically, it is possible for other strings to get this hash, but the probability is extremely low and can be approximated as impossible.)
Therefore, there are two important inferences.
Corollary 1: The hash of each block is different, and the block can be identified by the hash.
Corollary 2: If the content of the block changes, its hash will definitely change.
4. The non-modifiable nature of Hash
Blocks and hashes have a one-to-one correspondence. The hash of each block is based on the block header (Head).)computational. That is to say, the characteristic values ​​​​of the block header are connected together in order to form a very long string, and then the hash is calculated on this string.
Hash = SHA256 (block header)
The above is the calculation formula of block hash. SHA256 is the hash algorithm of the blockchain. Note that this formula only contains the block header and not the block body. In other words, the hash is uniquely determined by the block header.
As mentioned before, the block header contains a lot of content, including the hash of the current block body. , and the hash of the previous block. This means that if the content of the current block body changes, or the hash of the previous block changes, it will definitely cause the hash of the current block to change.
This point has great significance for blockchain. If someone modifies a block, the hash of the block changes. In order for subsequent blocks to still be connected to it (because the next block contains the hash of the previous block), the person must modify all subsequent blocks in sequence, otherwise the modified block will be removed from the blockchain . Due to the reasons mentioned later, hash calculation is very time-consuming, and it is almost impossible to modify multiple blocks in a short period of time, unless someone controls more than 51% of the computing power of the entire network.
It is through this linkage mechanism that the blockchain ensures its own reliability. Once the data is written, it cannot be tampered with. This is just like history, what happened happened, and it can’t be changed from now on.
Each block is connected to the previous block, which is where the name blockchain comes from.
5. Mining
Since synchronization between nodes must be ensured, the adding speed of new blocks cannot be too fast. Just imagine, you have just synchronized a block and are preparing to generate the next block based on it, but at this time, another node generates a new block, and you have to give up half of the calculations and synchronize again. Because each block can only be followed by one block, you can only generate the next block after the latest block. So, you have no choice but to sync as soon as you hear the signal.
So, the inventor of the blockchain, Satoshi Nakamoto (this is a pseudonym, and his true identity is still unknown) deliberately made it difficult to add new blocks. His design is that on average, the entire network can generate a new block every 10 minutes, which is only six per hour.
This output speed is not achieved through commands, but by deliberately setting up massive calculations. In other words, only through an extremely large amount of calculations can the effective hash of the current block be obtained and the new block added to the blockchain. Because the amount of calculation is too large, it cannot be done quickly.
This process is called mining, because the difficulty of calculating a valid hash is like finding a grain of sand that meets the conditions among the sand in the world. The machine that calculates hashes is called a mining machine, and the person who operates the mining machine is called a miner.
6. Difficulty coefficient
After reading this, you may have a question. People say that mining is difficult, but isn’t mining just about using a computer to calculate a hash? This is the strength of computers. How could it be?It becomes very difficult, why can’t it be calculated?
It turns out that not just any hash can be used, only hashes that meet the conditions will be accepted by the blockchain. This condition is particularly harsh, causing most hashes to fail to meet the requirements and must be recalculated.
It turns out that the block header contains a difficulty coefficient (difficulty), which determines the difficulty of calculating the hash. For example, the difficulty coefficient of the 100,000th block is 14484.16236122.
The blockchain protocol stipulates that the target value (target) can be obtained by dividing the difficulty coefficient by a constant. Obviously, the greater the difficulty coefficient, the smaller the target value.
The validity of the hash is closely related to the target value. Only hashes smaller than the target value are valid, otherwise the hash is invalid and must be recalculated. Since the target value is very small, the chance that the hash is smaller than this value is extremely slim, and it may be calculated 1 billion times before it is considered a hit. This is the fundamental reason why mining is so slow.
As mentioned earlier, the hash of the current block is uniquely determined by the block header. If the hash of the same block needs to be calculated repeatedly, it means that the block header must keep changing, otherwise it is impossible to calculate different hashes. All feature values ​​in the block header are fixed. In order to make the block header change, Satoshi Nakamoto deliberately added a random item called Nonce.
Nonce is a random value. The role of the miner is actually to guess the value of Nonce so that the hash of the block header can be smaller than the target value so that it can be written to the blockchain. Nonce is very difficult to guess. At present, we can only use trial and error one by one through exhaustive methods. According to the protocol, Nonce is a 32-bit binary value, which can reach a maximum of 2.147 billion. The Nonce value of the 100,000th block is 274148111. It can be understood that the miner started from 0 and calculated 274 million times before obtaining a valid Nonce value so that the calculated hash can meet the conditions.
If you are lucky, you may find Nonce in a while. If you are unlucky, you may have calculated it 2.147 billion times without finding the Nonce, that is, it is impossible to calculate a hash that meets the conditions for the current block body. At this time, the protocol allows miners to change the block body and start a new calculation.
7. Dynamic adjustment of difficulty coefficient
As mentioned in the previous section, mining is random, and there is no guarantee that a block will be produced in exactly ten minutes. Sometimes it can be calculated in one minute, and sometimes it may take several hours. No result. Overall, with the improvement of hardware equipment and the increase in the number of mining machines, the computing speed will definitely become faster and faster.
In order to keep the output rate constant at ten minutes, Satoshi Nakamoto also designed a dynamic adjustment mechanism for the difficulty coefficient. He stipulated that the difficulty factor should be adjusted every two weeks (2016 blocks). If the average block generation speed in these two weeks is 9 minutes, it means that it is 10% faster than the legal speed, so the next difficulty factor must be increased by 10%; if the average block generation speed is 11 minutes,This means that it is 10% slower than the legal speed, so the next difficulty factor must be lowered by 10%.
The difficulty coefficient is adjusted higher and higher (the target value is getting smaller and smaller), which makes mining more and more difficult.
8. Forks of the blockchain
Even if the blockchain is reliable, there is still an unresolved problem: if two people write data to the blockchain at the same time, that is to say, two people write data to the blockchain at the same time. Blocks join because they are connected to the previous block, forming a fork. Which block should be adopted at this time?
The current rule is that new nodes always adopt the longest blockchain. If there is a fork in the blockchain, it will look at which branch is behind the fork to reach 6 new blocks first (called six confirmations). Based on a block calculation of 10 minutes, it can be confirmed in one hour.
Since the generation speed of new blocks is determined by computing power, this rule means that the branch with the most computing power is the authentic blockchain.
9. Summary
Blockchain, as an unmanaged distributed database, has been running for 8 years since 2009 without major problems. This proves it works.
However, in order to ensure the reliability of data, blockchain also has its own price. The first is efficiency. You have to wait at least ten minutes to write data to the blockchain. All nodes synchronize the data, which requires more time. The second is energy consumption. The generation of blocks requires miners to perform countless meaningless calculations. This is Very energy consuming.
Therefore, the applicable scenarios of blockchain are actually very limited.
There is no management authority that all members trust
The written data does not require real-time use
The benefits of mining can make up for its own costs
If the above conditions cannot be met, then the traditional database is Better solution.
Currently, the largest application scenario (and possibly the only application scenario) of blockchain is the cryptocurrency represented by Bitcoin.

㈧ Blockchain Graduation Project Proposal

Background of the project research:

With the development of modern technology and information industry, at this stage , the fourth industrial revolution is beginning to take shape, and the world is about to enter a technological era centered on new technologies such as the Internet and artificial intelligence. At the same time, blockchain technology has emerged as the times require and has become a hot topic of concern to many international governments and industries. Blockchain technology has been regarded as the core technology with the greatest potential to trigger the fifth round of disruptive revolution after steam engines, electricity, information and Internet technology. In the past 10 years, with the strong support of the government and policies, the development situation of my country's philanthropy has been relatively optimistic. However, as the scale of charity continues to develop and expand, my country's public welfare undertakings have gradually revealed some shortcomings. The biggest problems existing in traditional public welfare undertakings are insufficient credibility, imperfect internal management of charitable organizations, and high costs. However, many Internet public welfare service companies are currently actively using the new technology of blockchain to solve this problem. Blockchain technology is decentralized, information is traceable and cannot be tampered with, openness, transparency, smart contracts and other characteristics can make up for the shortcomings of opaque information and low management efficiency in traditional public welfare undertakings. The introduction of blockchain technology into public welfare undertakings will bring new development opportunities to the charity industry.

The main content of the research: This topic mainly includes the following three aspects:

[if !supportLists] 1. [endif] Combination of blockchain technology and public welfare Problems that arise and solved.

[if !supportLists] 2. [endif] Make a public welfare query webpage based on blockchain technology

[if !supportLists] 3. [endif] The query system Application issues and explanations

Purpose of the research:

As the scale of my country’s public welfare continues to develop and expand, our shortcomings have also been exposed, including lack of credibility, and charitable organizations There is a lack of management, and the use of blockchain technology can solve this problem. This technology will track and store data and behaviors throughout the donation process, realize the complete disclosure of the public welfare chain, enable donors to effectively supervise, avoid shortcomings such as low efficiency and clear fund flows, control risks for public welfare projects, and improve Credibility and transparency of public welfare projects promote the development and progress of public welfare projects and enhance trust between people. According to the attributes and characteristics of the blockchain system, public welfare enterprises can implement full-cycle tracking, evidence storage and auditing of data and behaviors in the public welfare process, so that all parties involved in public welfare projects can conduct full-process tracking and effective supervision of the project, avoiding Due to the shortcomings of artificially reducing efficiency in public welfare, it provides a rational method for public welfare projects to control risks and judge effects, improve the transparency of public welfare undertakings, and promote the development of public welfare.

Significance of the project research: This project intends to develop an open and transparent system for tracking public welfare donations based on blockchain technology and combined with the actual development of public welfare undertakings in my country. Through in-depth analysis of blockchain technology and charity business, we found that blockchain technology has natural advantages in solving the problem of public welfare transparency. Blockchain technology can be understood as a distributed accounting method that can record all transaction information and ensure that it cannot be tampered with. This determines that wherever justice, fairness, and integrity are required, blockchain has great technology. Room to play. At the same time, the addition of smart contracts directly solves the business problem of earmarked funds.

Eventually, trust between citizens will be enhanced, donation channels will be accelerated, and the development of social donations will be promoted

2. Literature review (current status and development of relevant research at home and abroad Trend)

[if !supportLists] (1) [endif] Current status of foreign blockchain-related industries

China and Europe are gradually occupying the world in blockchain industry policies. The European Union established the European Blockchain Observation Forum in February 2018. The main responsibilities include: policy determination, industry-university-research linkage, cross-border BaaS

(Blockchain as a Service) service construction, standard open source formulation, etc. The group invested 5 million euros in Horizon2020 as a blockchain research and development fund ( Before December 19, 2018), it is expected that investment in blockchain will reach 340 million euros within three years (2018-2020). In the United States, due to different policies among states, although blockchain is still a craze among American start-ups, the promotion of industrial policy has been slow. The Middle East, led by Di Pai, is leading the trend of blockchain. The government is taking the lead and enterprises are cooperating to explore new technology applications of blockchain. Japan and South Korea are also relatively active in the Asia-Pacific region. Japan is dominated by NTT and the government provides support. South Korea uses finance as an entry point to explore blockchain applications. Isism is also a constant threat to all areas of Chinese society. A comprehensive review of the development status of new media culture in major foreign developed countries, summarizing experiences, and drawing lessons have certain implications for the development of new media culture in China.

[if !supportLists] (2) [endif] Current status of domestic new media research

The State Council of China issued the "Thirteenth Five-Year Plan for National Informatization", Blockchain New technologies such as big data, artificial intelligence, and machine deep learning have become the focus of the country’s layout. The People's Bank of China issued the "Thirteenth Five-Year Plan for the Development of Information Technology in China's Financial Industry", which clearly proposed to actively promote research on the application of new technologies such as blockchain and artificial intelligence, and organize pilot projects for national digital currency. In October 2017, the Ministry of Industry and Information Technology released the "White Paper on China's Blockchain Technology and Application Development", which is the first official guidance document for blockchain.

Governments across the country, especially in coastal areas, have established blockchain experimental sites and research institutes. At present, the governments of Shenzhen, Hangzhou, Guangzhou, Guiyang and other places are actively establishing blockchain development zones and providing special support policies. China Guangzhou officially released 10 Guangzhou blockchain strategies in December 2017 to create a blockchain enterprise technology innovation zone in Huangpu District and Development Zone. In March 2018, the Shenzhen Municipal Economic, Trade and Information Commission issued the "Notice of the Municipal Economic, Trade and Information Commission on Organizing and Implementing the Second Batch of Support Plan for the New Generation Information Technology and Information Security Transformation of Shenzhen's Strategic Emerging Industries in 2018". The district Blockchain is on the list of support directions. This is the fifth local government in China to introduce support policies for blockchain after Guangzhou, Guiyang, and Gehangzhou.

(3) Current status of blockchain in the open source field

Hyperledger (Hyperledger)

Hyperledger (Hyperledger) was initiated by the Linux Foundation in 2015 The open source project of blockchain digital technology and transaction verification has attracted the participation of many companies including IBM, Intel, Fujitsu, UPS, Cisco, Huawei, Redhat, Oracle, Samsung, Tencent Cloud, Internet Finance, etc. It currently has more than 200 members. unit, Aache Foundation founder Bran Behlendorf serves as the executive director of the ledger project.

The goal of the Hyperledger project is to allow members to work together to build an open platform to meet user cases from many different industries and simplify business processes. Process Ledger has multiple blockchain platform projects, including the Fabric project contributed by BIM, the Sawtooth project contributed by Intel, and Iroha, Burrow, Indy, etc.

The development status of blockchain in the field of standards

ITU-T

ITU-T (International Telecommunication Union Standardization Organization) from 2016 to 2017 At the beginning of the year, SG16 (Study Group), SG17 and SG20 respectively launched research on the overall needs and security of distributed ledgers to attract applications in the Internet of Things. Established three focus groups (Focus Group on Distributed Ledger (FG DLT), Focus Group on Data Processing and Management (FG DPM), and Focus Group on Fiat Digital Currency (FG DFC)), focusing on blockchain and distributed ledger respectively. Technology application and service research, establishing a trustworthy Internet of Things and smart city data management framework based on blockchain, and carrying out standardization work on blockchain applications based on digital currency. Huawei serves as the chairman of the Architecture Group of the Focus Group on Distributed Ledger (FG DLT) and the Blockchain Group of the Focus Group on Data Processing and Management (FGDPM).

Two committees of CCSA (China Communications Standards Association) have established subgroups and projects respectively:

CCSA TC10 (Internet of Things Technical Working Committee) Established in October 2017, the Internet of Things Blockchain Subgroup: Responsible for the application research and standardization of blockchain technology in the Internet of Things and its covered areas such as smart cities, Internet of Vehicles, edge computing, Internet of Things big data, Internet of Things industry applications, logistics and intelligent manufacturing, and is led by China China Unicom technical experts serve as team leaders, and Huawei technical experts serve as deputy team leaders.

CCSA TC1 (Internet and Application TechnologyThe Blockchain and Big Data Working Group under the Working Committee has completed two blockchain industry standards: "Blockchain: Part 1 Overall Technical Requirements for Blockchain" and "Blockchain: Part 2 Evaluation Indicators and Evaluation Methods" 》, Huawei actively participated in it.

JPEG

During the 78th JPEG Conference in February 2018, the JPEG Committee organized a special session on blockchain and distributed ledger technology and their impact on the JPEG standard. Meeting. Taking into account the potential impact of technologies such as blockchain and distributed ledgers on future multimedia, the committee decided to establish an ad hoc group to explore use cases and standardization needs related to blockchain technology in a multimedia environment, with a focus on imaging and multimedia applications. standardization work.

IETF

The "Decentralized Internet Infrastructure ProposedRG

(Research Group) was established at the IETF99 meeting in June 2017, planning to study the blockchain architecture. and corresponding standards. In 2018, IETF will likely pay more attention to the implementation and development of blockchain interconnection standards on blockchain.



3. Proposed research methods (programs, technical routes, etc.) and feasibility studies

This topic mainly studies the application of blockchain technology to charitable donations. Research methods adopted:

1. Use literature methods to collect relevant theories, use information retrieval, screening and other methods to collect literature materials and related theories, understand the current situation of blockchain technology, and master blockchain decentralization technology.
< br /> 2. Use a method that combines theory and practice to combine the technology with public welfare. Complete the improvement of the system.

3. Use the method of comparative analysis to learn from two domestic and foreign Discuss the current development status of new media operations, as well as existing problems in the development of new media operation models in my country, and look forward to the development prospects of this technology field.

Feasibility demonstration:

1. Technical feasibility, the research goals involved in this topic, already have considerable theoretical foundations at home and abroad. Through literature survey, we can learn about actual, reliable and useful information data, and the actual requirements are not difficult.

2. Economic feasibility. The research on this topic can be accessed through the Internet and libraries. It is convenient and feasible and does not require a lot of economic consumption. Therefore, from an economic point of view, it is completely feasible.

3. Operational feasibility, requirements of this topicFor the combination of blockchain technology and public welfare, especially the tracing of these applications, and the comprehensive analysis of the graduation project system on this topic, we can use the data we collected through the study of existing literature and the study of existing documents. , organize and analyze, apply what you have learned, and complete this topic completely. From an operability point of view, it is completely feasible.

4. Expected results (or expected results)

1. Through research on the data, clarify the relevant concepts of blockchain technology, skillfully use dapp, and create a web page.

2. Through distributed applications, creating a system that allows the public to quickly browse and understand the public welfare process will increase convenience for the further development of my country's public welfare undertakings.

3. I hope that I can continue to learn and make progress from the process of writing this paper. Being able to master the relevant knowledge of blockchain will be helpful to your future career.

㈨ What does blockchain mean? What are the characteristics of blockchain?

Regarding the technology of blockchain, I believe many friends have already paid attention to it. Blockchain It can be said to be a hot topic right now, with news media reporting heavily on it claiming it will create the future. So what does blockchain mean? What are the characteristics of blockchain? Today we will introduce the blockchain to you in detail, and hope that you will have a deep understanding after reading it.
What does blockchain mean?
Blockchain is a new application model of computer technologies such as distributed data storage, point-to-point transmission, consensus mechanism, and encryption algorithms. The so-called consensus mechanism is a mathematical algorithm that establishes trust and obtains rights and interests between different nodes in the blockchain system.
Blockchain is also an important concept of Bitcoin. The "2014-2016 Global Bitcoin Development Research Report" released by the Internet Finance Laboratory of Tsinghua University PBC School of Finance and Sina Technology mentioned that blockchain is Bitcoin's underlying technology and infrastructure.
Blockchain is essentially a decentralized database and serves as the underlying technology of Bitcoin. The blockchain is a series of data blocks generated using cryptographic methods. Each data block contains information about a Bitcoin network transaction and is used to verify the validity of its information (anti-counterfeiting) and generate the next block.
In a narrow sense, blockchain is a chain data structure that combines data blocks in a sequential manner in chronological order, and is cryptographically guaranteed to be non-tamperable and non-forgeable. Ledger.
Broadly speaking, blockchain technology uses block chain data structures to verify and store data, uses distributed node consensus algorithms to generate and update data, uses cryptography to ensure the security of data transmission and access, and uses A new distributed infrastructure and computing paradigm that uses smart contracts composed of automated script code to program and manipulate data.
What are the characteristics of blockchain?
Through the summary analysis of blockchain, we can get the characteristics of blockchainThe main points are as follows: 1. The first is the trust of deintermediation. This is also repeatedly emphasized. What Songwei and yesterday said is not decentralization but deintermediation. It coincides with combine.
2. The second feature is its stability, reliability, and sustainability. Because it is a distributed network architecture, no central node can be hit or attacked, so in the overall technical layout It has stronger stability, reliability and sustainability.
3. Third, its strong security and consensus mechanism do not require the entry of a third party, but are achieved through a technology, a previously scheduled technology to complete the entire transaction.
4. The fourth is the openness, transparency and non-tamperability of transactions. Many practitioners in the industry have shared these characteristics with you, so these are the four characteristics of the blockchain.
Because of these characteristics, blockchain can receive huge attention from many financial institutions and many industries in the future or now.
The above is what the editor brings to you. What does blockchain mean? What are the characteristics of blockchain? of the entire content.