区块链的技术7个层次是什么,区块链的技术7个层次包括

A. The hierarchical structure of the blockchain (what is Layer0/1/2 of the blockchain)

The hierarchical structure is the basis for the data processing and operation of the blockchain .

In order to find a scalability solution for the blockchain, the blockchain referred to in the academic research field (usually in papers) is divided into three layers: Layer0, Layer1 and Layer2.

Generally, the blockchain system is mainly divided into six layers: application layer, incentive layer, consensus layer, network layer and data layer, which are mainly reflected in the early Bitcoin system. With the emergence of smart contracts, a contract layer was added between the application layer and the incentive layer, mainly reflected in the Ethereum system.

The content of each layer is shown in the figure above, but the technologies used in different specific systems may be different. For example, the consensus layer mainly completes the consensus between nodes, except for the workload proof. The mechanism (Proof of Work) also includes the Proof of Stake mechanism (Proof of Stake) and the Byzantine Fault Tolerance mechanism (BFT).

The data layer, network layer, and consensus layer constitute The underlying foundation of the blockchain hierarchy is also the three essential elements of the blockchain. Without any one of them, it cannot be called a true blockchain technology.

Blockchain hierarchical structure correspondence The comparison between the OSI system 7-layer model and the TCP/IP 4-layer model is shown in the figure below.

If we focus on the four layers of TCP/IP, especially the "application layer" above, We will see that it is possible that the blockchain separates the application layer that was originally focused only on information transmission into a new layer dedicated to value transfer. Therefore, we can think that the four layers of TCP/IP are split into five layers , consider the blockchain as a layer of TCP/IP: the value layer.

It is generally believed that Bitcoin, Ethereum, and EOS are blocksIt is also interesting to look at the layers of the representatives of chains 1.0, 2.0, and 3.0:

From Bitcoin to Ethereum, the contract layer has been added. From Ethereum to EOS, due to the adoption of DPOS, the incentive layer is actually merged into the consensus layer. EOS adds two layers: ① Tool layer to make it easier to develop applications; ② Ecological layer, its own positioning is an open source software, so others can use its open source software to build industry chains and domain chains.

Xu Zhong and Zou Chuanwei wrote a central bank working paper, discussing blockchain from an economics perspective and trying to provide a Token paradigm. Among them, they actually gave a layered model, this time it is internal and external layering: the inner layer is consensus, which is divided into: Token, smart contract, consensus algorithm; at the boundary of consensus and blockchain, is the blockchain Other information within; outside the boundaries of the blockchain, is the Internet and the physical world.

In order to improve performance, some systems actually layer their distributed networks. That is, not all nodes are equal.
For example, the following is the layering of EOS.

In order to make blockchain useful, some people are discussing it from other perspectives. Zhu Feng of ENChain.Asia proposed the "Seven-layer Self-Organizing Business Model" in the BAO white paper. This model was quoted in the "Model and Practice of Token Economy" (0.2) report as the "Seven-layer Self-Organizing Business Model" Model".

However, it should be noted that the "incentive layer" here is similar to the incentive layer we usually call blockchain, but it is different. When we discussed the incentive layer before, we often discussed it from the perspective of the native tokens of the public chain, while the incentive layer here is discussed at the pass level.

In a December 2018 report "Construction and Analysis of the Four-Layer Application Model of Blockchain", Huobi Research Institute gave a four-layer application model, which is very interesting:< br />
References:
1. Ten years of blockchain: various layers
http://www.360doc.com/content/18/1211/10/53358875_800866301.shtml
2. How much do you know about the six hierarchical structures of blockchain? - Zhihu
https://zhuanlan.hu.com/p/98126049
3. Introduction to the six hierarchical structures of blockchain - Blockchain - Electronic Enthusiast Network
http ://www.elecfans.com/blockchain/1138839.html

B. What is blockchain technology? What exactly is blockchain? What is blockchain

In a narrow sense , Blockchain is a chain 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 data transmission and access. It is a new distributed infrastructure and computing method that uses smart contracts composed of automated script codes to program and operate data securely.

[Infrastructure]

Generally speaking, the blockchain system consists of data layer, network layer, consensus layer, incentive layer, contract layer and application layer composition. Among them, the data layer encapsulates the underlying data blocks and related basic data and basic algorithms such as data encryption and timestamps; the network layer includes distributed networking mechanisms, data dissemination mechanisms, and data verification mechanisms; the consensus layer mainly encapsulates network nodes Various consensus algorithms; the incentive layer integrates economic factors into the blockchain technology system, mainly including the issuance mechanism and distribution mechanism of economic incentives; the contract layer mainly encapsulates various scripts, algorithms and smart contracts, and is the core of the blockchain The basis of programmable features; the application layer encapsulates various application scenarios and cases of the blockchain. In this model, the chain block structure based on timestamps, the consensus mechanism of distributed nodes, economic incentives based on consensus computing power, and flexible programmable smart contracts are the most representative innovations of blockchain technology.

Extended information:

[Blockchain core technology]

Blockchain mainly solves the trust and security issues of transactions, so it addresses this issue Four technological innovations:

1. Distributed ledger, which means transaction accounting is performed by multiple nodes distributed in different places.Completed together, and each node records a complete account, so they can all participate in supervising the legality of the transaction and can also jointly testify for it.

The uniqueness of blockchain's distributed storage is mainly reflected in two aspects: First, each node of the blockchain stores complete data according to the block chain structure. Traditional distributed storage generally stores The data is divided into multiple parts for storage according to certain rules. Second, the storage of each node in the blockchain is independent and has equal status, relying on the consensus mechanism to ensure the consistency of storage, while traditional distributed storage generally synchronizes data to other backup nodes through the central node.

No node can record ledger data independently, thus avoiding the possibility of a single bookkeeper being controlled or bribed to record false accounts. Also because there are enough accounting nodes, theoretically speaking, the accounts will not be lost unless all nodes are destroyed, thereby ensuring the security of the accounting data.

2. Asymmetric encryption and authorization technology. Transaction information stored on the blockchain is public, but account identity information is highly encrypted and can only be accessed with authorization from the data owner. , thus ensuring data security and personal privacy.

3. The consensus mechanism is how all accounting nodes reach a consensus to determine the validity of a record. This is both a means of identification and a means of preventing tampering. Blockchain proposes four different consensus mechanisms, which are suitable for different application scenarios and strike a balance between efficiency and security.

The consensus mechanism of the blockchain has the characteristics of "the minority obeys the majority" and "everyone is equal". "The minority obeys the majority" does not entirely refer to the number of nodes, but can also be the computing power and the number of shares. Or other characteristic quantities that the computer can compare. "Everyone is equal" means that when a node meets the conditions, all nodes have the right to give priority to the consensus result, which will be directly recognized by other nodes and may eventually become the final consensus result.

4. Smart contracts. Smart contracts are based on these trustworthy and non-tamperable data and can automatically execute some predefined rules and terms. Take insurance as an example. If everyone's information (including medical information and risk occurrence information) is true and trustworthy, it will be easy to automate claims settlement in some standardized insurance products.

In the daily business of insurance companies, although transactions are not as frequent as those in the banking and securities industries, the reliance on trusted data continues unabated. Therefore, the author believes that using blockchain technology from the perspective of data management can effectively help insurance companies improve their risk management capabilities. Specifically speaking, it is mainly divided into risk management of policyholders and risk supervision of insurance companies.

Blockchain-Network

C. The technical classification of blockchain mainly includes

1. Public chain, no official organization, no Management organization, no central server. Participating nodes freely access the network in accordance with the rules of the system. There is no control and the nodes work based on a consensus mechanism. (subversive: Absolutely credible and open)

D. What are the core blockchain technologies of blockchain technology?

What is the hottest Internet topic at the moment, I don’t need to tell you. I also know that it 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 blockchain networks, Merkle trees are used to summarize all transactions in a block.Easy information, and finally generates 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 exampleIn the PeerCoin PoS mechanism, the Bitcoin with the longest chain age has a greater chance of obtaining accounting rights. NXT and Blackcoin use a formula to predict the next accounting node. The more tokens you own, the greater the probability of being selected as an accounting node. In the future, Ethereum will also switch from the current PoW mechanism to a PoS mechanism. Judging from the information currently available, Ethereum's PoS mechanism will use nodes to place bets on the next block. The winner of the bet will receive an additional Ethereum currency award. Those who do not win will be deducted Ether coins to reach consensus on the next block.
DPoS (DelegatedProof-Of-Stake, share authorization certificate): DPoS is easy to understand and is similar to the modern corporate board of directors system. The DPoS mechanism adopted by BitShares is that shareholders vote to select a certain number of witnesses. Each witness has two seconds of authority to generate blocks in order. If the witness cannot generate a block within the given time slice, The block generation authority is given to the witness corresponding to the next time slice. Shareholders can replace these witnesses at any time by voting. This design of DPoS makes the generation of blocks faster and more energy-saving.
Distributed Consistency Algorithm: Distributed Consistency Algorithm is based on traditional distributed consistency technology. Among them are Byzantine fault-tolerant algorithms that solve the Byzantine Generals problem, such as PBFT (Byzantine fault-tolerant algorithm). In addition, distributed consensus algorithms (Pasox, Raft) that solve non-Byzantine problems are not explained in this article. This type of algorithm is currently a commonly used consensus mechanism in alliance chain and private chain scenarios.
Taken together, POW is suitable for public chains. If you build a private chain, it is more suitable to use POS because there is no trust problem in verification nodes; and because there are untrustworthy local nodes in the alliance chain, it is more suitable to use DPOS.
Blockchain technology----Incentive layer: 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.
BlockchainTechnology----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 deployed on the blockchain Implemented by decentralized, trusted shared script code. 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.

E. What are the blockchain technology frameworks

The current mainstream blockchain architecture contains six levels: network layer, data layer, consensus layer, incentive layer, contract layer and application layer. The positions of the data layer and the network layer are reversed in the figure, and their main uses will be detailed in the next section.
Network layer: The essence of the blockchain network is a P2P (Peer-to-peer) network. The resources and services in the network are scattered on all nodes. The transmission of information and the implementation of services are directly between the nodes. It can be carried out in a short period of time without the intervention of intermediate links and servers. Each node both receives and generates information. The nodes synchronize information by maintaining a common blockchain. When a node creates a new block, it notifies other nodes in the form of broadcast, and other nodes receive the information. The block is then verified and a new block is created based on the block, thereby achieving the role of the entire network jointly maintaining an underlying ledger. Therefore, the network layer will involve the design of P2P network, propagation mechanism, verification mechanism, etc. Obviously, these designs can affect the confirmation speed of block information. The network layer can be used as a research direction in the scalable solution of blockchain technology;
Data layer: The underlying data of the blockchain is a block + linked list data structure, which includes data blocks, chain structures, timestamps, hash functions, Merkle trees, asymmetric encryption and other designs. Among them, data blocks and chain structures can be used as improvement directions for data layer research in the scalable solution of blockchain technology.
Consensus layer: It is the basis for highly dispersed nodes to achieve rapid consensus on the validity of block data. The main consensus mechanisms include POW (Proof Of Work) and POS (Proof of Stake). Mechanism), DPOS (Delegated Proof of Stake Delegated Proof of Stake Mechanism) and PBFT (Practical Byzantine Fault Tolerance), etc., which have always been the highlight of the scalable solutions of blockchain technology.
Incentive layer: It is what everyone often calls a mining mechanism. It is used to design a certain economic incentive model and encourage nodes to participate in the security verification of the blockchain, including the design of issuance mechanisms and distribution mechanisms, etc. This level of improvement does not seem to be directly related to blockchain scalability.
Contract layer: mainly refers to various script codes, algorithm mechanisms, smart contracts, etc. Strictly speaking, this layer is missing in the first generation of blockchains, so they can only conduct transactions and cannot be used in other fields or perform other logical processing. The emergence of the contract layer makes it possible to use blockchains in other fields. has become a reality. This part of Ethereum includes two parts: EVM (Ethereum Virtual Machine) and smart contracts. Improvements at this level seem to provide potential new directions for blockchain scalability, but there seems to be no direct connection in structure
Application layer: It is the display layer of the blockchain, including various application scenarios and cases. . For example, Ethereum uses truffle and web3-js. The application layer of the blockchain can be the mobile terminal, the web terminal, or it can be integrated into the existing server, and the current business server is regarded as the application layer. Improvements at this level seem to provide potential new directions for blockchain scalability, but there does not seem to be a direct connection in structure.
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F. What are the three levels in the blockchain technology architecture

The three levels in the blockchain technology are as follows:

Protocol layer

The so-called protocol layer refers to the lowest level technology. This level is usually a complete blockchain product, similar to the operating system of our computer. It maintains network nodes and only provides APIs for calling. Usually the official will provide a simple client (commonly known as a wallet). The function of this client wallet is also very simple. It can only create an address, verify the signature, transfer payment, check the balance, etc.

Extension layer

This layer is similar to a computer driver and is designed to make blockchain products more practical.

The application layer

This level is similar to various software programs in computers. It is a product that ordinary people can use directly. It can also be understood as a B/S architecture. The browser side of the product. Applications at this level are currently almost blank.

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

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