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Ⅰ 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 kind of function is easy to verify, but difficult 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 finally generateA unified hash value of all transaction information in this block. Any change in transaction information in the block will cause the Merkle tree to change.
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 then 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 (Proof of Stake, Proof of Stake): PoS mechanism, a distributed consensus mechanism that requires nodes to provide proof of a certain number of tokens to obtain competition 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, PeercoinCoin) 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: Develop a "salary system" for accounting nodes
Core technology 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----ContractLayer: Giving the ledger programmable features
Core technology 8. Smart contract:
Smart contract is a set of scenario-responsive programmed rules and logic, which is a decentralized and programmable system deployed on the blockchain. Implemented by letter sharing script code. Usually, 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 of the introduction to the core technology of blockchain.

II The core of blockchain technology is

The core of blockchain technology
is the consensus algorithm. The essence of the consensus algorithm is in the
distributed network< br />Under the condition that each node does not trust each other, by providing evidence
scarce resources
, a
Nash equilibrium
game field is formed to win the trust of all parties. , quickly reach agreement between various nodes and complete tasks synchronously.

Ⅲ What are the three core technologies of blockchain

Introduction to the 7 core technologies of blockchain operation 2018-01-15
1. Blockchain Link
As the name suggests, blockchain is a chain composed of blocks. Each block is divided into two parts: block header and block body (including transaction data). The block header includes the hash (PrevHash) value (also known as the hash value) of the previous block used to implement the block link and the random number (nonce) used to calculate the mining difficulty. The hash value of the previous block is actually the hash value of the header of the previous block, and the rules for calculating random numbers determine which miner can obtain the power to record the block.
2. Consensus Mechanism
Blockchain was born with Bitcoin and is the basic technical architecture of Bitcoin. Blockchain can be understood as a decentralized accounting system based on the Internet. Decentralized digital currency systems like Bitcoin require blockchain to ensure the consistency of accounting by honest nodes without a central node. Therefore, the core of blockchain technology is a consensus mechanism that reaches consensus on the legality of transactions among individuals who have no basis for trust in each other without central control.
There are currently four main categories of blockchain consensus mechanisms: PoW, PoS, DPoS, and distributed consensus algorithms.
3. Unlocking script
Script is an important technology for automatic verification and automatic execution of contracts on the blockchain. Each output of each transaction does not strictly point to an address, but to a script. A script is like a set of rules that restricts how the recipient can spend the input.Remove the locked assets.
The legality verification of transactions also relies on scripts. Currently it relies on two types of scripts: locking scripts and unlocking scripts. The locking script is a condition added to the output transaction, implemented through a script language, and is located at the output of the transaction. The unlocking script corresponds to the locking script. Only if the conditions required by the locking script are met, the corresponding assets on this script can be spent, which is located at the input of the transaction. Many flexible conditions can be expressed through scripting languages. The interpretation script is similar to a "virtual machine" in our programming field, which is distributed and runs on every node in the blockchain network.
4. Transaction rules
Blockchain transactions are the basic units that constitute blocks, and are also the actual effective content that the blockchain is responsible for recording. A blockchain transaction can be a transfer or other transactions such as the deployment of smart contracts.
In the case of Bitcoin, a transaction refers to a payment transfer. The transaction rules are as follows:
1) The input and output of the transaction cannot be empty.
2) For each input of the transaction, if its corresponding UTXO output can be found in the current transaction pool, the transaction will be rejected. Because the current transaction pool is a transaction that has not been recorded in the blockchain, and each input of the transaction should come from a confirmed UTXO. If found in the current transaction pool, it is a double spend transaction.
3) For each input in the transaction, its corresponding output must be UTXO.
4) Each input unlocking script (unlocking) must work with the corresponding output locking script (locking) to verify the compliance of the transaction.
5. Transaction priority
The priority of blockchain transactions is determined by the blockchain protocol rules. For Bitcoin, the priority of a transaction being included in a block is determined by the time it takes for the transaction to be broadcast to the network and the size of the transaction. As the time it takes for a transaction to be broadcast to the network increases and the chain age of the transaction increases, the priority of the transaction is increased and will eventually be included in the block. For Ethereum, the priority of a transaction is also related to the transaction fee that the publisher of the transaction is willing to pay. The higher the transaction fee that the publisher is willing to pay, the higher the priority of the transaction being included in the block.
6.Merkle proof
The original application of Merkle proof is the Bitcoin system (Bitcoin), which was described and created by Satoshi Nakamoto in 2009. The Bitcoin blockchain uses Merkle proofs in order to store transactions in every block. This makes the transaction unable to be tampered with and makes it easy to verify whether the transaction is included in a specific block.
7.RLP
RLP (Recursive Length Prefix, recursive length prefix encoding) is a main encoding method for object serialization in Ethereum. Its purpose is to encode any nested sequence of binary data.

IV Blockchain EcosystemWhat are the three core values ​​of WEN?

Consensus, circulation and creation. It just so happens that the core values ​​of WEN ecology are based on these three.

IV What does the core technology of blockchain include?

First of all, we can take a look at the official website explanation of blockchain technology. In a narrow sense, blockchain is a chained data structure that combines data blocks in a sequential manner in chronological order, and is a cryptographically guaranteed distributed ledger that cannot be tampered with or forged.
Broadly speaking, blockchain technology uses block chain data structures to verify and store data, uses distributed node consensus algorithms to generate and update data, and uses cryptography to ensure the security of data transmission and access. A new distributed infrastructure and computing paradigm that uses smart contracts composed of automated script codes to program and manipulate data.
As everyone may know, blockchain technology is an underlying architecture independent of the Bitcoin system. From an architectural model perspective, it is a set of distributed ledgers. The so-called ledger is naturally used to record Account.
In blockchain technology, in order to generate accounting records, there must be transactions and flows of funds. Therefore, the earliest blockchain technology has the cryptocurrency corresponding to its main network. As a circulating item, the circulation transaction records of cryptocurrency between various accounts on the blockchain main network will be recorded on the main network.
Different from other transaction record databases, transaction records on the blockchain technology mainnet will be recorded on all block nodes (i.e. all data blocks) in the mainnet. This is The so-called decentralization principle means that in blockchain technology, there is no central database to save all records. Each block on the chain has transaction data for the entire chain, that is, every data block , are all centers.
Another characteristic of blockchain technology is that it cannot be tampered with, because every transaction on the Daqing blockchain will be recorded in all blocks on the chain, so any single data block cannot be tampered with. Records cannot be changed, and even if you do, the real data will be recorded in all other data blocks, and each set of data can be traced back to when it first appeared.
Because of these characteristics of blockchain technology, after the advent of Bitcoin, blockchain has also received a lot of attention, and many people have begun to want to use blockchain technology to create a centerless and traceable system. , data that does not change to ensure the credibility of the data.
However, blockchain technology also faces many problems, such as a single application scenario, native erroneous data that cannot be modified, and currencies stolen by hackers that cannot be recovered.

Ⅵ Understand the Internet blockchain in one article

Understand the Internet blockchain in one article

Understand the Internet blockchain in one article. To understand the blockchain, We have to study the brief history of the technological development of blockchain starting from the birth of the Internet, and explore the dynamics generated by blockchain.Therefore, we can infer the future of 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 group 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 got Jia Dongfeng. After the record was completed, a complete block was generated, but remember, this was only the first game. In the entire blockchain , this is just one node. After the 8 rounds mentioned at the beginning, there are 8 nodes (blocks). 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.I didn’t bring any cash, so I asked a beautiful woman (centralized) to keep records in a notebook and record how much money she won and how much she lost in each game. 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, it has expanded from the earliest military and scientific research 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 development of the Internet took a major step forwardThe most critical step is the official introduction of the Internet core communication technology-TCP/IP protocol jointly developed by American scientists Vinton Cerf and Robert Kahn.

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 on 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 completed 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, it will not affect the transmission of the entire Internet information.

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 othersTens of millions of client computers do not retain information and only obtain information data when accessing the server. This structure is often called the B/S architecture of the Internet, which 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 mailing list of the underground hacker site Slashdot 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 a member of the family of cryptographic functions defined by the American National Institute of Standards and Technology.

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. Phishing attackof victims.

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 in addition to blockchain, to 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 fully and clearly explain the blockchain to the public. 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. Many Internet giants such as Alibaba, Sina, Amazon, etc. all have centralized B/S architecture. Simply put, it is data Put it in a giant server, and our ordinary users can access the servers of Alibaba, Sina and other websites through mobile phones and personal computers.

Since the beginning of the 21st century, many software applications have emerged to freely share music, videos, and paper materials. Most of them useIt uses a peer-to-peer network (P2P) architecture, that is, there is no central server. Everyone's personal computers are both 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 network (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. Every 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.

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 to25. 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. This process of issuing coins 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 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 are in front of the TThe CP/IP introduction mentioned 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 will have difficulty using blockchain. 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 was learnedXi Jinping established a data server center to become the relay node of the blockchain, which can also be accessed using 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. There are multiple ganglia with the same functions, all of which can command body activities and reactions. However, as organisms evolve, these ganglia gradually merge. When they evolve into higher In biology, the central nervous system appeared, which contains a large number of neurons that interact with each other.

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 an unstoppableA "world currency" regulated by the government.

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.

VII The three key points in blockchain technology are:

The consensus algorithm, the use of asymmetric encryption for data signature, and the storage of chain blocks. Blockchain is a chain composed of blocks one after another. Each block stores a certain amount of information, and they are connected into a chain in the order in which they were generated. This chain is saved in all servers. As long as one server in the entire system can work, the entire blockchain is safe. These servers are called nodes in the blockchain system, and they provide storage space and computing power support for the entire blockchain system. If you want to modify the information in the blockchain, you must obtain the consent of more than half of the nodes and modify the information in all nodes. These nodes are usually in the hands of different subjects, so tampering with the information in the blockchain is a serious problem. An extremely difficult thing. Compared with traditional networks, blockchain has two core characteristics: first, data is difficult to tamper with, and second, it is decentralized. Based on these two characteristics, the information recorded in the blockchain is more authentic and reliable, and can help solve the problem of people's mutual distrust. Blockchain originated from Bitcoin. On November 1, 2008, a person claiming to be Satoshi Nakamoto published the article "Bitcoin: A Peer-to-Peer Electronic Cash System", which elaborated on P2P network technology and encryption technology. , timestamp technology, blockchain technology and other electronic cash system architectural concepts, which marks the birth of Bitcoin. Two months later, the theory came into practice, and on January 3, 2009, the first genesis block with serial number 0 was born. A few days later, block number 1 appeared on January 9, 2009, and was connected to the genesis block number 0 to form a chain, marking the birth of the blockchain. Blockchain in the narrow sense is a chain data structure that combines data blocks in a sequential manner in chronological order, and is cryptographically guaranteed to be non-tamperable.A modified and unforgeable distributed ledger. Generalized 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 smart contracts composed of automated script codes. , a new distributed infrastructure and computing paradigm for programming and manipulating data.

ⅧWhat are the blockchain technologies?

The concept of blockchain can be said to be very popular. At the Internet Finance Summit, no one said that blockchain technology is out. What is chain technology?

Blockchain technology can be either a public classification (anyone can see it) or a permissioned network (only permissioned people can see it), solving supply chain challenges. Because it is An immutable record, so it is shared among network participants and updated in real time.

Blockchain technology - data layer: Designing the data structure of the account book

Core technology 1. Block_ _;Chain:

Technically, a block is a data structure that records transactions, reflecting the capital flow of the transaction. The transaction blocks that have been reached in the system are connected to form the main chain, and all nodes participating in the calculation are It records the main chain or a part of the main chain.

Each block is composed 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 transaction quantity and transaction details. The block header includes The current version number, the previous block address, the timestamp (recording the time when the block was generated, accurate to the second), the random number (recording the answer value to the mathematical question related to decrypting the block), the target hash value of the current block, and the Merkle number Information such as the root value of the source mill. 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 from the Hash algorithm to a fixed-length code. The principle is a one-way hash function based on cryptography. This function is easy to verify, but difficult to interpret. The industry usually uses y =hash(x) means that this hash function realizes the hash value y of computing x.

Commonly used hash algorithms include MD5, SHA-1, SHA-256, SHA-384, SHA-512, etc. Taking the SHA256 algorithm as an example, input any data into SHA256 and you will get a 256-bit Hash value (hash value). Its characteristics: the same data input will get the same result. The input data changes a little (for example, 1 becomes 0) will get completely different results. The result is that the forward calculation (the Hash value corresponding to the data calculation) is very simple. The reverse calculation is extremely difficult and is considered impossible under the current scientific and technological conditions.

Core technology 3. Merkle tree:

Merkle tree is a hash binary tree that can quickly verify the integrity of large-scale data. In the blockchain network, Merkle_黄髂jumimiofuzhenglu The weapon is the salaryman's side_The husband is inciting the salaryman's side⒌The endurance is also the V burden橹湩伟曰簩izaipan⒌浵Jijengmou_erkle trees.

Core technology 4. Asymmetric encryption algorithm:

Asymmetric encryption algorithm is a secret method for keys. A key and a key are required. The public key and the private key are a pair. If you use the public key to encrypt data, you can only use the corresponding private key to decrypt it to obtain the corresponding data value. If you use the private key to sign the data, you can only use the corresponding public key. Verify the signature and verify that the sender of the information is the owner of the private key.

Since encryption and decryption use two different keys, the algorithm is called an asymmetric encryption algorithm, while symmetric encryption is used in encryption and decryption. The same key is used in the process.

Blockchain mitigation technology - network layer: realizing the centralization of charging nodes

Core technology 5, P2P network:

P2P network (peer-to-peer network), also known as peer-to-peer technology, is an Internet system without a central server and user groups exchanging information. Different from the central network system with a central server, each client of the peer-to-peer network is a node, and there are Server functions. Domestic Xunlei software uses P2P technology. The P2P network has the characteristics of centralization and strengthening.

Blockchain technology-consensus layer: allocate the task load of charging nodes

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