区块链的七大核心是什么,区块链的七大核心技术

『一』 What are the core blockchain technologies of blockchain technology?

What is the hottest Internet topic at the moment? 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 seconds), random number (recording the value of decrypting the answer to the math question related to the block), target hash value of the current block, and 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 finallyGenerate a 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 the 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 (ProofofStake, Proof of Stake): PoS mechanism requires nodes to provide proof of a certain number of tokens to obtain a distributed consensus mechanism for competing for blockchain accounting rights. If you rely solely on the token balance to determine the bookkeeper, you will inevitably make the rich win, which will lead to the centralization of bookkeeping rights and reduce the fairness of the consensus. Therefore, different PoS mechanisms use different methods to increase the amount of money based on the proof of equity. The randomness of accounting rights avoids centralization. For example, Peercoin (PeerCoin) PoS mechanism, the Bitcoin with the longest chain age has a greater chance of obtaining accounting rights. NXT and Blackcoin use a formula to predict the next accounting node. The more tokens you own, the greater the probability of being selected as an accounting node. In the future, Ethereum will also switch from the current PoW mechanism to a PoS mechanism. Judging from the information currently available, Ethereum's PoS mechanism will use nodes to place bets on the next block. The winner of the bet will receive an additional Ethereum currency award. Those who do not win will be deducted Ether coins to reach consensus on the next block.
DPoS (DelegatedProof-Of-Stake, share authorization certificate): DPoS is easy to understand and is similar to the modern corporate board of directors system. The DPoS mechanism adopted by BitShares is that shareholders vote to select a certain number of witnesses. Each witness has two seconds of authority to generate blocks in order. If the witness cannot generate a block within the given time slice, The block generation authority is given to the witness corresponding to the next time slice. Shareholders can replace these witnesses at any time by voting. This design of DPoS makes the generation of blocks faster and more energy-saving.
Distributed Consistency Algorithm: Distributed Consistency Algorithm is based on traditional distributed consistency technology. Among them are Byzantine fault-tolerant algorithms that solve the Byzantine Generals problem, such as PBFT (Byzantine fault-tolerant algorithm). In addition, distributed consensus algorithms (Pasox, Raft) that solve non-Byzantine problems are not explained in this article. This type of algorithm is currently a commonly used consensus mechanism in alliance chain and private chain scenarios.
Taken together, POW is suitable for public chains. If you build a private chain, it is more suitable to use POS because there is no trust problem in verification nodes; and because there are untrustworthy local nodes in the alliance chain, it is more suitable to use DPOS.
Blockchain technology----Incentive layer: 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----Contract layer: giving the ledger programmable features
Core technology 8. Smart contract:
Smart contract is a set of scenario-responsive programmed rules and logic, which is decentralized and deployed on the blockchain. Trusted shared script code is implemented. Normally, after the smart contract is signed by all parties, it is attached to the blockchain data in the form of program code, and is recorded in a specific block of the blockchain after being propagated through the P2P network and verified by nodes. Smart contracts encapsulate a number of predefined states and transition rules, scenarios that trigger contract execution, response actions under specific scenarios, etc. The blockchain can monitor the status of smart contracts in real time, and activate and execute the contract by checking external data sources and confirming that specific trigger conditions are met.
The above is what blockchain technologies the editor has brought to you? All content of the introduction to the core technology of blockchain.

『二』 Six core algorithms of blockchain technology

Six core algorithms of blockchain technology
Blockchain core algorithm one: Byzantine Agreement
The story of Byzantium probably goes like this: The Byzantine Empire has huge wealth, and its 10 neighboring countries have been around for a long time. However, Byzantium’s high walls are towering and impregnable, and no single neighbor can successfully invade. Any invasion by a single neighbor will fail, and it is also possible that it will be invaded by 9 other neighbors. The Byzantine Empire's defensive capabilities were so strong that at least half of its ten neighbors had to attack at the same time to be able to break through. However, if one or several of the neighbors agree to attack together, but betrayal occurs during the actual process, then the invaders may all be annihilated. So each party acted cautiously and did not dare to trust its neighbors easily. This is the Byzantine Generals Problem.
In this distributed network: each general has a message ledger that is synchronized with other generals in real time. The signature of each general in the ledger can be used to verify the identity. If any messages are inconsistent, you can know which generals the messages are inconsistent with. Even if there is inconsistent information, as long as more than half agree to attack, the minority obeys the majority, and a consensus is reached.
Thus, in a distributed system, although there are bad guys, bad guys can do anything (not restricted by the protocol), such as not responding, sending error messages, sending different decisions to different nodes, and combining different wrong nodes. Get up and do bad things, etc. However, as long as most people are good people, it is entirely possible to achieve consensus in a decentralized manner
Blockchain Core Algorithm 2: Asymmetric Encryption Technology
In the above Byzantine Agreement, if one of the 10 generals Several messages initiated at the same time will inevitably cause chaos in the system, causing each to have its own attack time plan, making it difficult to act in a consistent manner. Anyone can initiate offensive information, but who will send it? In fact, this only requires adding a cost, that is: only one node can spread the information within a period of time. When a node sends a unified attack message, each node must sign and stamp the message from the initiator to confirm their identity.
In today’s view, it is verySymmetric encryption technology can completely solve this signature problem. The asymmetric encryption algorithm uses two different keys for encryption and decryption. These two keys are the "public key" and "private key" that we often hear. Public keys and private keys generally appear in pairs. If a message is encrypted with a public key, the private key corresponding to the public key is required to decrypt it; similarly, if a message is encrypted with a private key, the public key corresponding to the private key is required to decrypt it.
Blockchain Core Algorithm Three: Fault Tolerance Issue
We assume that in this network, messages may be lost, damaged, delayed, sent repeatedly, and the order received is inconsistent with the order sent. In addition, the behavior of nodes can be arbitrary: they can join and exit the network at any time, they can discard messages, forge messages, stop working, etc. Various human or non-human failures may also occur. Our algorithm provides excellent fault tolerance for a consensus system composed of consensus nodes. This fault tolerance includes both security and availability, and is applicable to any network environment.
Blockchain core algorithm 4: Paxos algorithm (consensus algorithm)
The problem solved by the Paxos algorithm is how a distributed system can reach agreement on a certain value (resolution). A typical scenario is that in a distributed database system, if the initial state of each node is consistent and each node performs the same sequence of operations, then they can finally obtain a consistent state. In order to ensure that each node executes the same command sequence, a "consistency algorithm" needs to be executed on each instruction to ensure that the instructions seen by each node are consistent. A general consensus algorithm can be applied in many scenarios and is an important issue in distributed computing. There are two models for node communication: shared memory and message passing. The Paxos algorithm is a consensus algorithm based on the message passing model.
Blockchain Core Algorithm Five: Consensus Mechanism
The blockchain consensus algorithm is mainly proof of work and proof of equity. Taking Bitcoin as an example, in fact, from a technical point of view, PoW can be regarded as reused Hashcash. Generating proof of work is a random process in terms of probability. To mine a new confidential currency, when generating a block, all participants must agree, and the miner must obtain PoW proof of work for all data in the block. At the same time, miners must constantly observe and adjust the difficulty of this work, because the network requirement is to generate a block every 10 minutes on average.
Blockchain Core Algorithm 6: Distributed Storage
Distributed storage is a data storage technology that uses the disk space on each machine through the network and combines these dispersed storage resources into a virtual Storage devices, data are stored dispersedly in every corner of the network. Therefore, distributed storage technology does not store complete data on each computer, but splits the data and stores it in different computers. It's like storing 100 eggs, not in the same basket, but in different places. The total sum is 100.

『三』WhatWhat is the core content of blockchain

The core content of blockchain is the contract layer
1. Decentralization
This is the subversive feature of blockchain, there is no center Institutional and central servers, all transactions occur in client applications installed on everyone’s computer or mobile phone.
Achieve point-to-point direct interaction, which not only saves resources, makes transactions autonomous and simplified, but also eliminates the risk of being controlled by centralized agents.
2. Openness
Blockchain can be understood as a public accounting technology solution. The system is completely open and transparent.
The account books are open to everyone, enabling data sharing and anyone can check the accounts. .
Blockchain is a transparent and shared general ledger. This ledger is open to the entire network. Once you get its public key, you will know how much money is in the ledger. Therefore, any value conversion is completely Interested people in the world can watch you, and the conversion is confirmed by the miners, so it is an Internet consensus mechanism.
3. Irreversible, non-tamperable and encrypted security
The blockchain adopts a one-way hash algorithm. Each newly generated block is strictly advanced in linear order according to time. The irreversibility and irrevocability of time will lead to any Attempts to intrude and tamper with data information in the blockchain can easily be traced, leading to rejection by other nodes. The cost of counterfeiting is extremely high, which can limit related illegal activities.
(3) Extended reading of the seven cores of blockchain:
1. Concept definition
What is blockchain? From a technological perspective, blockchain involves many scientific and technical issues such as mathematics, cryptography, Internet and computer programming. From an application perspective, simply put, blockchain is a distributed shared ledger and database, which has the characteristics of decentralization, non-tampering, full traceability, traceability, collective maintenance, openness and transparency. These characteristics ensure the "honesty" and "transparency" of the blockchain and lay the foundation for creating trust in the blockchain. The rich application scenarios of blockchain are basically based on the ability of blockchain to solve the problem of information asymmetry and achieve collaborative trust and consistent action among multiple subjects [7].
Blockchain is a new application model of computer technologies such as distributed data storage, point-to-point transmission, consensus mechanism, and encryption algorithms. Blockchain is an important concept of Bitcoin. It is essentially a decentralized database.
Two, features
Decentralization. Blockchain technology does not rely on additional third-party management agencies or hardware facilities, and there is no central control. In addition to the self-contained blockchain itself, each node realizes self-verification, transmission and management of information through distributed accounting and storage. Decentralization is the most prominent and essential feature of blockchain.
Openness. The foundation of blockchain technology is open source. In addition to the private information of the transaction parties being encrypted, the data of the blockchain is open to everyone. Anyone can query the blockchain data and develop related applications through the public interface. Therefore, the entire System information is highly transparent.
Independence. Based on consensus specifications and protocols (likeSimilar to various mathematical algorithms such as the hash algorithm used by Bitcoin), the entire blockchain system does not rely on other third parties. All nodes can automatically and securely verify and exchange data within the system without any human intervention.
Security. As long as you cannot control 51% of all data nodes, you cannot manipulate and modify network data at will. This makes the blockchain itself relatively safe and avoids subjective and artificial data changes.
Anonymity. Unless required by legal regulations, technically speaking, the identity information of each block node does not need to be disclosed or verified, and information transfer can be carried out anonymously

『四』The core of blockchain technology is

The core of blockchain technology
is the consensus algorithm. The essence of the consensus algorithm is to use evidence
in the
distributed network
under the condition that each node does not trust each other. >Scarce resources
form a
Nash equilibrium
game field, win the trust of all parties, quickly reach agreement among various nodes, and complete tasks synchronously.

『五』What is blockchain technology and what are the core components of blockchain technology

From a technical perspective and an architectural perspective, I will tell you about it in popular language. , my understanding of blockchain.

What exactly is blockchain? Block chain, in a word, blockchain is a storage system, and the storage system is more detailed. Block chain is a distributed storage system without an administrator, and each node owns all data.

What do common storage systems look like?

First, let’s take a look at how to ensure high availability?

Ordinary storage systems usually use "redundancy" to solve high availability problems. As shown in the figure above, if the data can be copied into several copies and redundantly spread to multiple places, high availability can be ensured. If the data in one place is down, there will still be data in another place. For example, the master-slave cluster of MySQL has this principle, and the RAID of the disk also has this principle.

Two points that need to be emphasized here are: data redundancy often causes consistency problems

1. For example, in the master-slave cluster of MySQL, there will actually be a delay in reading and writing. Sometimes, it actually means that there is inconsistency between reading and writing for a short period of time. This is a side effect of data redundancy.

2. The second point is that data redundancy often reduces writing efficiency, because data synchronization also consumes resources. If you look at single-point writing, if two slave libraries are added, the writing efficiency will actually be affected. Ordinary storage systems use redundancy to ensure high data availability.

Then the second question is, can an ordinary storage system perform multiple writes?

The answer is yes, for example, take this picture as an example:

In fact, MySQL can do a dual-master master-slave synchronization, dual-master master-slave synchronization, two nodes ,samecan be written. If you want to build a multi-machine room and multi-active data center, in fact, multi-machine room and multi-active data center also requires data synchronization. What should be emphasized here is that multi-point writing often leads to consistency issues of write-write conflicts. Taking MySQl as an example, assuming that the attribute of a table is an auto-increment ID, then the data in the database is now 1234, then one of the nodes When writing, a piece of data is inserted, it may become 5. Then these 5 pieces of data are synchronized to another master node. Before the synchronization is completed, if another writing node also inserts a piece of data, it will also generate A piece of data with an auto-incrementing ID of 5 is obtained. Then, after it is generated, it is synchronized to another node, and then when the synchronized data arrives, it will conflict with the two local 5s, and the synchronization will fail, which will cause write consistency conflicts. This problem will occur if there are multiple writes.

How to ensure consistency when writing multiple points?

Weixin's "Swan Master Class" will give you more technical work

『Lu』 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. The record cannot be changed. Even if you change it, the real data will be recorded in all other data blocks, andEach 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.

『撒』What is the concept of blockchain

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

The essence of the blockchain is a distributed public ledger. Anyone can verify this ledger, but no single user can control it. Participants in a blockchain system jointly maintain a ledger: it can only be modified according to strict rules and consensus.

The development of blockchain has gone through three stages:

1. Incubation period: 2009-2012, the economic form was dominated by Bitcoin and its industrial ecology.

2. Embryonic period: The period is from 2012 to 2015. Blockchain entered the public eye with Bitcoin, new wallet payment and remittance companies appeared, and the blockchain economy spread to the financial field. The underlying technology of blockchain continues to innovate. Blockchain technology is divorced from the Bitcoin system.

3. Development period: In 2016, industry applications began to be explored, and a large number of blockchain startups emerged. The popularity of ICO in 2017 brought unprecedented attention to blockchain.

(7) Extended reading of the seven cores of blockchain:

Three characteristics of three blockchains:

1. The core idea of ​​the blockchain is decentralization: in the blockchain system, the rights and obligations between any nodes are equal, and all nodes have the ability to vote with computing power, thus ensuring recognition. The result is recognized by more than half of the nodes. Even if it suffers a severe hacker attack, as long as the number of nodes controlled by the hacker does not exceed half of the total number of global nodes, the system will still be able to operate normally and the data will not be tampered with.

2. The biggest disruption of blockchain lies in the establishment of credit: in theory, blockchain technology can make WeChat Pay and Alipay no longer valuable. The Economist made a vivid metaphor for blockchain: simply put, it is “a machine that creates trust.” Blockchain allows people to collaborate without trusting each other and without a neutral central authority. Combating counterfeit currency and financial fraud will no longer be needed in the future.

3. The collective maintenance of blockchain can reduce costs: In a centralized network system, the maintenance and operation of the system rely on the operation, maintenance and operation of platforms such as data centers, and costs cannot be omitted. Anyone can participate in the nodes of the blockchain. While participating in the recording, each node also verifies the recording results of other nodes.accuracy, maintenance efficiency is improved, and costs are reduced.

In one sentence, blockchain touches money, trust and power, which are the fundamental foundations on which human beings rely for survival.