最成熟的区块链技术是什么,最成熟的区块链技术是

最近，区块链技术正在迅速发展，它被认为是未来数字经济的核心技术。其中，最成熟的区块链技术包括智能合约、去中心化应用和联盟链。

智能合约是指在区块链网络上运行的一种特殊类型的协议，它可以自动执行和管理用户之间的交易。智能合约的优点在于它可以让用户摆脱繁琐的手续，提高交易效率，减少交易成本，并且可以保证交易的安全性。此外，智能合约还可以让用户更好地控制自己的资产，以及实现去中心化的自治组织。

去中心化应用（DApp）是一种以区块链技术为基础的分布式应用程序，它可以利用区块链的去中心化特性，提供更安全、可靠和可信的服务。去中心化应用的优点在于它可以实现安全、可靠、可信的服务，并且可以极大地提高效率，减少交易成本，消除信任问题，从而实现去中心化的自治组织。

联盟链是一种特殊的区块链网络，它可以由多个组织或个人共同维护，而不是由一个中心化的机构来维护。联盟链的优点在于它可以提供更高的安全性和可靠性，并且可以更好地实现去中心化的自治组织。此外，联盟链还可以提供更低的交易成本，更快的交易速度，以及更高的可扩展性。

总之，最成熟的区块链技术包括智能合约、去中心化应用和联盟链，它们的优点是可以提供更高的安全性和可靠性，更低的交易成本，更快的交易速度，以及更高的可扩展性。因此，未来的数字经济将会大量使用这些技术，以满足用户的需求。

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『一』The core of blockchain technology is

The core of blockchain technology
is the consensus algorithm, and the essence of the consensus algorithm is
In the distributed network
, under the condition that each node does not trust each other, by providing evidence
scarce resources
, a game field of
Nash equilibrium
is formed, and the game is won. With the trust of all parties, consensus can be quickly reached between various nodes and tasks can be completed synchronously.

『二』What are the three core technologies of blockchain

Introduction to the 7 core technologies of blockchain operation 2018-01-15
1. Blockchain Chain links
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. 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 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 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 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,It can also be other matters 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.

『三』What is the core technology of blockchain

Simply put, blockchain is a distributed database that provides Byzantine fault tolerance and ensures ultimate consistency; From the data structure point of view, it is a chained data block structure based on time series; from the node topology point of view, all its nodes are redundant backups of each other; from the operation point of view, it provides a public and private key management system based on cryptography to manage the account.
Perhaps the above concept is too abstract, let me give you an example so that you can understand it easier.
You can imagine that there are 100 computers distributed around the world. The network between these 100 machines is a wide area network, and the owners of these 100 machines do not trust each other.
So, what kind of algorithm (consensus mechanism) can we use to provide it with a trustworthyenvironment, and makes:
The data exchange process between nodes cannot be tampered with, and the generated historical records cannot be tampered with;
The data of each node will be synchronized to the latest data, and the latest data will be verified Effectiveness;
Based on the principle that the minority obeys the majority, the data maintained by the overall node can objectively reflect the exchange history.
Blockchain is a technical solution created to solve the above problems.
2. The core technology components of blockchain
Whether it is a public chain or a consortium chain, it requires at least four modules: P2P network protocol, distributed consistency algorithm (consensus mechanism), encryption signature algorithm, Account and storage model.
1. P2P network protocol
P2P network protocol is the lowest module of all blockchains and is responsible for network transmission and broadcast of transaction data, node discovery and maintenance.
Usually what we use is the Bitcoin P2P network protocol module, which follows certain interaction principles. For example: when connecting to other nodes for the first time, you will be required to confirm the status according to the handshake protocol. After the handshake, you will start to request the address data and block data of the Peer node.
This P2P interactive protocol also has its own set of instructions, which are reflected in the command field of the Message Header. These commands provide the upper layer with node discovery, node acquisition, block header acquisition, Block acquisition and other functions, these functions are very low-level and very basic functions. If you want to learn more, you can refer to the Peer Discovery chapter in the Bitcoin Developer Guide.
2. Distributed consensus algorithm
In the field of classic distributed computing, we have non-Byzantine fault-tolerant algorithms represented by the Raft and Paxos algorithm families, as well as the PBFT consensus algorithm with Byzantine fault-tolerant characteristics.
If we look at it from the perspective of technological evolution, we can draw a picture in which blockchain technology has expanded the original distributed algorithm economically.
In the picture, we can see that computer applications were mostly single-point applications at the beginning, and cold disaster recovery was used for high availability and convenience. Later, they developed into multi-active in different places. These multi-active in different places may use load balancing. and routing technology. With the development of distributed system technology, we have transitioned to distributed systems based on Paxos and Raft.
In the field of blockchain, PoW workload proof algorithm, PoS equity proof algorithm, and DPoS proxy equity proof algorithm are mostly used. The above three are the mainstream consensus algorithms in the industry. These algorithms are similar to the classic distributed consensus algorithm. The difference is that they incorporate the concept of economic games. Below I will briefly introduce these three consensus algorithms respectively.
PoW: Usually refers to solving a mathematical problem of specific difficulty under given constraints. Whoever solves it faster will win.Can obtain accounting rights (block production rights). This solution process is often converted into a calculation problem, so when competing for speed, it becomes who has a better calculation method and whose equipment has better performance.
PoS: This is a proof-of-stake mechanism. Its basic concept is that the difficulty of generating a block should be proportional to your stake (ownership ratio) in the network. The core idea of ​​its implementation is: Use the coin age (CoinAge) of your locked tokens and a small proof of work to calculate a target value. When the target value is met, you will be able to obtain accounting rights.
DPoS: A simple understanding is to convert the bookkeepers in the PoS consensus algorithm into a small circle composed of a specified number of nodes, instead of everyone can participate in bookkeeping. This circle may have 21 nodes or 101 nodes, depending on the design. Only nodes in this circle can obtain accounting rights. This will greatly improve the throughput of the system, because fewer nodes means that the network and nodes are controllable.
3. Encrypted signature algorithm
In the field of blockchain, the most commonly used hash algorithm is the hash algorithm. The hash algorithm has the characteristics of collision resistance, irreversibility of the original image, and problem friendliness.
Among them, problem friendliness is the basis for the existence of many PoW currencies. In Bitcoin, the SHA256 algorithm is used as the calculation method for proof of work, which is what we call the mining algorithm.
In Litecoin, we will also see the Scrypt algorithm, which is different from SHA256 in that it requires large memory support. In some other currencies, we can also see mining algorithms based on the SHA3 algorithm. Ethereum uses an improved version of the Dagger-Hashimoto algorithm, named Ethash, which is an IO-intractable algorithm.
Of course, in addition to the mining algorithm, we will also use the RIPEMD160 algorithm, which is mainly used to generate addresses. Most of the numerous Bitcoin derivative codes adopt the Bitcoin address design.
In addition to addresses, we will also use the core and the cornerstone of the blockchain Token system: public and private key cryptographic algorithms.
In the Bitcoin code, ECDSA is basically used. ECDSA is a combination of ECC and DSA. The entire signature process is similar to DSA, except that the algorithm used in the signature is ECC (Elliptic Curve Function).
Technically, we start by generating a private key, then generate a public key from the private key, and finally generate an address from the public key. Each of the above steps is an irreversible process, which means that the public key cannot be derived from the address. , derived from the public key to the private key.
4. Account and transaction model
From the initial definition, we know that blockchain can be considered a distributed database from a technical perspective only. Then,What type of database do most blockchains use?
When I designed the Metaverse blockchain, I referred to a variety of databases, including NoSQL’s BerkeleyDB and LevelDB, and some currencies use SQL-based SQLite. As the underlying storage facilities, most of them are lightweight embedded databases. Since they do not involve the ledger characteristics of the blockchain, these storage technologies are no different from those used in other situations.
The ledger characteristics of blockchain are usually divided into UTXO structure and ledger structure based on Accout-Balance structure, which we also call the ledger model. UTXO is the abbreviation of "unspent transaction input/output", which translated means "unspent transaction input/output".
This is an accounting mode for Token transfer in the blockchain. Each transfer appears in the form of input and output; in the Balance structure, there is no such mode.

『四』 Which companies are relatively mature in developing blockchain technology

Blockchain refers to the collective maintenance of a reliable database through decentralization and trustlessness. technical solutions. In layman's terms, blockchain technology refers to a way for all people to participate in bookkeeping. You can think of the database as a big ledger, so who will keep this ledger becomes very important. Currently, whoever owns the system keeps the accounts. Tencent keeps the accounts of WeChat, and Alibaba keeps the accounts of Taobao. But now in the blockchain system, everyone in the system has the opportunity to participate in accounting. If there are any data changes within a certain period of time, everyone in the system can do accounting. The system will judge the person who has the fastest and best accounting during this period, write his recorded content into the ledger, and record this Within a period of time, the contents of the ledger are sent to all other people in the system for backup. In this way, everyone in the system has a complete ledger. In this way, we call it blockchain technology.
As a distributed network accounting system, blockchain has six characteristics: decentralization, openness and transparency, non-tampering, non-forgery, distributed storage, and smart contracts. These are also the leaders in blockchain technology. progress and development. There are also some companies currently developing applications of blockchain technology, and Heshu Software is one of them, which has developed a peer-to-peer trading system and hyperledger.

『Wu』 There are many blockchain applications now. What kind of blockchain applications are good? Where can I get a clear understanding of them?

I want to know about blockchain For chain applications, you can refer to many books and opinions, including "Blockchain in Pictures", "Blockchain: Reshaping the Economy and the World", "New Economic Blueprint and Introduction", as well as articles from the Binance community, including comments on the Binance community I also know this platform in detail, and its strength is awesome.

1. What is blockchain

Blockchainain), as the name suggests, is composed of block and chain. It is a new application model of computer technologies such as distributed data storage, point-to-point transmission, consensus mechanism, and encryption algorithm. It is a chained data structure that combines data blocks in chronological order and is cryptographically guaranteed to be an untamperable, unforgeable, safe and trustworthy distributed ledger.

In 2008, Satoshi Nakamoto first proposed the concept of blockchain and encrypted digital currency in his paper "Bitcoin: A Peer-to-Peer Electronic Cash System". Starting from Bitcoin, blockchain has become the underlying technology of various digital currencies.

2. The working principle of blockchain:

1. Basic concepts include:
(1) Transaction: one operation will change the ledger status once , such as adding a record;
(2) Block: records transactions and status data that occurred within a specified time, which is a consensus and preservation of the current ledger status;
(3) Chain ( Chain): It is composed of blocks connected in chronological order and is a log record of the entire state change.
Understanding the working concept of blockchain, it is not difficult to understand its working principle. Suppose there is a distributed data record book. This record book only allows additions, deletions and changes. Its structure is composed of individual data records. A linear chain formed by "blocks" connected in series (this is also the origin of the name "blockchain"). To add new data, it must be placed in a new block. The maintenance node can propose a new block. However, a certain consensus mechanism must be used to reach agreement on the final selected block.

2. Take Bitcoin as an example to see how the blockchain works.

Bitcoin blocks are divided into two parts: block header and block body.

3. Core advantages and characteristics of blockchain

1. Decentralization
Block The processes of verification, accounting, storage, maintenance and transmission of chain data are all based on the distributed system structure. There is no centralized hardware or management organization. The rights and obligations of any node are equal. The data blocks in the system are composed of Nodes with maintenance functions in the entire system are jointly maintained.
2. Open and transparent
The system is open. In addition to the private information of the transaction parties being encrypted, the blockchain data is open to everyone, and anyone can query the blockchain through the public interface. Data and development related applications, so the entire system information is highly transparent.
3. Security
The blockchain adopts consensus-based specifications and protocols (such as a set of open and transparent algorithms) to enable all nodes in the entire system to exchange data freely and securely in a trustless environment. , so that trust in "people" is changed to trust in machines, and any human intervention has no effect.
4. Information cannot be tampered
Once the information is verified and added to the blockchain, it will be stored permanently. Unless more than 51% of the nodes in the system can be controlled at the same time (almost impossible), modifications to the database on a single node are invalid, so the area The data stability and reliability of blockchain are extremely high.
5. Anonymity
Since the exchange between nodes follows a fixed algorithm, the data interaction does not require trust (the program rules in the blockchain will judge whether the activity is valid by itself), so the counterparty does not need to Making the other party trust you by disclosing your identity is very helpful for the accumulation of credit.

4. Classification of blockchains

Currently, the most mainstream classification of blockchains is to divide blockchains into public blockchains (Public Blockchain) based on different participants. ), Private Blockchain and Consortium Blockchain.

1. Public chain: Anyone can participate in the use and maintenance, and can obtain effective confirmation of the blockchain. The public chain is the earliest blockchain and the most widely used blockchain at present. , typically such as the Bitcoin blockchain, the information is completely public.

If a permission mechanism is introduced, it will include private chain and alliance chain.
2. Private chain: A company or individual only uses blockchain technology and has exclusive write permission to the blockchain, and the information is not made public. At present, conservative giants (traditional finance) all want to experiment with private blockchains, and the application products of private blockchains are still being explored.
3. Consortium chain: It is a blockchain between the public chain and the virtual chain, jointly controlled by multiple organizations. The use of this chain is managed with authority and can be controlled by managers and also based on The manager's wishes are open to others.
In addition, according to the different usage scenarios and purposes of blockchain, it is divided into currency chains for the purpose of digital currency, property rights chains for the purpose of recording property rights, crowdfunding chains for the purpose of crowdfunding, etc. .

5. Analysis of specific application scenarios of blockchain

1. Information anti-counterfeiting

On May 28, Tencent CEO Ma Huateng spoke at the Guiyang Digital Expo The problem of Moutai anti-counterfeiting has been raised: the anti-counterfeiting method based on cloud-based comprehensive blockchain technology will be much more efficient than traditional anti-counterfeiting methods. In future anti-counterfeiting verification scenarios, users may only need to perform a simple scan with their mobile phone to obtain a large amount of complete information based on different dimensions.

Take Moutai as an example:

Distillery address, production workshop, operating employees, inspectors, factory time, transportation vehicle information and driver information,

The vintage source of raw materials for wine, raw material suppliers, storage warehouse numbers, raw material transportation vehicles and driver information,

All information can be accurately traced, permanently recorded and cannot be tampered with.

The authenticity can be easily verified based on the above information.

2. Food safety issues

As early as November last year, Walmart had cooperated with IBM to use blockchain technology to track food sources to ensure food safety and increase food circulation to reduce costs. For large companies such as Walmart, For supermarkets, in the past, when food safety problems occurred, it took several days to investigate the source of the problematic food. After using this technology, only one piece of information about the product is needed to achieve accurate traceability, including the food origin, inspector, supplier, Important information such as logistics and transportation can quickly detect problems within a few minutes. Currently, products tracked using blockchain include packaging products in the United States and pork in China.

3. Information Security

Blockchain technology is promoting a revolution in information security technology. Three major security threats: man-in-the-middle attack, data tampering, and DDoS

(1) Identity protection

PKI is a common public key encryption used in various communication applications such as email, messaging applications, and websites. technology. However, since most PKI implementations rely on a centralized trusted third-party certification authority (CA) to issue, activate and store user certificates, hackers can attack PKI to fake user identities or crack encrypted information.

CertCoin is the first blockchain PKI implementation, coming from MIT, which removes the centralized certification center and uses the blockchain as a distributed ledger of domain names and public keys.

Pomcor Company: Blockchain PKI implementation path: retain the certification center and use the blockchain to store hash values ​​of issued and activated certificates. Users can verify the authenticity of certificates through decentralized and transparent sources, while also improving network access performance through local authentication of keys and signatures based on blockchain copies.

(2) Data integrity protection

GuardTime has developed a keyless signature architecture (KSI) based on blockchain technology to replace key-based data authentication technology. KSI stores hashes of the original data and files on the blockchain, runs hashing algorithms to verify other copies, and compares the results with the data stored on the blockchain. Any tampering with the data will be quickly detected because the original hash table is stored on millions of nodes.

(3) Protection of critical infrastructure

The "Achilles' heel" of the Internet, DDoS has entered the TB era, and DDoS is still the easiest way for hackers to defeat large targets at low cost. As a weapon, DNS services are the primary target for hackers to carry out large-scale damage, but blockchain technology is expected to fundamentally solve it.

The distributed storage of blockchain makes hacker attacks lose focus. Nebulis is developing a distributed DNS system using the Ethereum blockchain and the InterPlanetary Internet File System (IPFS, a distributed alternative to HTTP product) to register and resolve domain names. The biggest weakness of DNS is caching. Caching makes DDoS attacks possible and is also the bane of centralized governments censoring social networks and manipulating DNS registrations. A highly transparent, distributed DNS system can haveEffectively prevent any entity, including the government, from arbitrarily manipulating records.

IV. Financial Industry

(1) Digital Currency: Improving the convenience of currency issuance and use

For example, foreign Bitcoin and Ethereum, our country currently There are Nuo Compao and so on.

From the use of physical transactions, to physical currency and credit currency, to the rise of the Bitcoin network, more people are aware of the distributed ledger blockchain technology behind it, and gradually outside of digital currency applied in many scenarios.

(2) Cross-border payment and settlement: realize point-to-point transactions and reduce intermediate costs

Transfer and payment. At present, the most mature application of blockchain technology is payment and transfer. Blockchain technology can avoid complicated systems, save the process of inter-bank reconciliation and review, and speed up settlement; using virtual currency does not require the intervention of a clearing house, reducing transaction fee. The clearing procedures of each country are different. It takes 2 or 3 days for a single remittance to arrive, which is inefficient and accounts for a large proportion of funds in transit. No longer going through a third party, point-to-point payment is formed through blockchain technology. Eliminating the need for third-party institutions, you can make payments throughout the day, receive money in real time, quickly withdraw cash, and reduce hidden costs, helping to avoid financial risks. It is timely and convenient.

(3) Bills and supply chain financial business: reduce human intervention, reduce costs and operational risks

Point-to-point value transfer, physical bills or central system for control and verification; intermediary will be eliminated and human intervention reduced. Improved efficiency, smoother financing channels, lower risks, and benefits for all parties.

(4) Securities issuance and trading: realize quasi-real-time asset transfer and accelerate transaction clearing speed

The application of blockchain technology can make the securities trading process simpler, more transparent and faster , Reduce IT systems with repetitive functions and improve the efficiency of market operations. For stocks, blockchain can eliminate paper and pen or spreadsheet records, reduce human errors in transactions, and improve the transparency and traceability of trading platforms. Citi and Nasdaq collaborate to advance blockchain applications.

(5) Customer credit reporting and anti-fraud: reduce legal compliance costs and prevent financial crimes

Customer information and transaction records recorded in the blockchain help banks identify Abnormal transactions and effectively prevent fraud. The technical characteristics of blockchain can change the existing credit reporting system. When banks perform "know your customer" (KYC), the data of customers with bad records will be stored in the blockchain.

Equity crowdfunding: Equity crowdfunding based on blockchain technology can achieve decentralized trust and investors’ returns are guaranteed.

5. Supply chain management

Distributed ledger system, participants track the ownership of assets throughout the process, and can be used to track auto parts when moving between countries and factories.

Toyota is developing blockchain technology solutions for its core parts supply chain operations. Using a large amount of data helps Toyota more efficiently ensure the accuracy of recorded data and can also help manage the supply chain. At the same time, blockchainThe supply chain can control warranty, repair goods related costs and specifications through smart contracts, and transactions throughout the product life cycle are irreversible.

The shipping industry’s first public solution, deployed by Maritime Transport International (MTI), uses blockchain supply chain technology to share Verified Gross Mass (VGM) information for shipping containers. Information about container VGM is important to ensure ships are properly stowed and to prevent accidents at sea and in ports. VGM data is stored on the blockchain supply chain, providing a permanent record for port officials, shipping companies, shippers and cargo owners. This replaces cumbersome logs, spreadsheets, data brokers and private databases.

Logistics Integrity System Wagonbang Wagonbang launched a blockchain-based financial solution for logistics enterprises, aiming to provide enterprises with reliable financial services. It can not only help drivers solve the problem of loan difficulty, but also change the current situation of lack of integrity in the industry and help build a logistics integrity system. Help build the identity chain of logistics companies and create a trusted data ecosystem for logistics companies. Using a transparent, supervisory, and traceable algorithm model, we screen reliable companies that need financial support and provide them with financial services. On the other hand, at the technical level, various law enforcement departments are linked to jointly punish dishonest companies.

6. Government management

(1) Election

Based on the characteristics of blockchain technology and considering the shortcomings of current election technology, we will build an open source , Blockchain applications for elections, voting and lottery, we call it ElectionChain. We hope to optimize election and voting technology to make voting more open and transparent, reduce human manipulation, and allow voters to verify their election results.

Including identity authentication, multi-chain system, flash investment protocol, consensus algorithm EDPOS, privacy protection, voting mechanism design, decentralized ELC rental market, storage solutions, smart contracts, etc.

(2) Government services

Aiming to realize an e-government digital ecosystem based on blockchain technology and provide citizens with government services and an automated mechanism for the business of various government departments, it must be All areas of national government affairs are combined to form a common information space, including government agencies, economic data, financial transactions and social fields. This ecosystem should also include registries and corresponding software for building smart contract-based applications and platforms for government agencies, businesses and public users.

『Lu』 What are the mainstream blockchain technologies?

This article attempts to provide an overview of blockchain-related technology schools and mainstream platforms as a guide for learning the blockchain technology system. , intended to inspire discussion and promote consensus in the blockchain development community. The schools of blockchain technology plan ahead of the battle. If you want to invest in the field of blockchain development, you must at least find out who the current players are and what their respective opinions and strengths are. There are no certain rules for dividing blockchain technology schools. As far as I can see, there may be the following four ways: The first is according to the node access rules.It is divided into public chain, private chain and alliance chain. The representatives of the public chain are naturally Bitcoin and Ethereum, the private chain is the most famous R3 Corda, and the representative work of the alliance chain is Fabric under the name of Hyperledger. Public chains focus on anonymity and decentralization, while private chains and consortium chains focus on high efficiency, and often set entry barriers. These differences between public chains, private chains and alliance chains are all reflected in technology. For example, private chains and alliance chains assume that the number of nodes is not large, and the PBFT algorithm can be used to form a consensus. The public chain assumes a large and dynamically changing node network. Using PBFT is too inefficient, and only a lottery-like algorithm can be used to determine opinion leaders. This means that it is difficult for private chains and alliance chains to become public chains, and although it is easy to use public chains to make alliance chains or private chains, it is not plug-and-play. Scholars cannot ignore this difference. The second is that according to the sharing goal, it is divided into two groups: shared ledger and shared state machine. Bitcoin is a typical shared ledger, and Chain and BigchainDB should also fall into this category. These blockchain systems share a general ledger between various nodes, so it is more convenient to connect with financial applications. In another large type of blockchain system, each node shares a state machine that can complete Turing complete calculations, such as Ethereum and Fabric. They all change the state of the shared state machine by executing smart contracts, thereby achieving various complex functions. . The third is to divide the blockchain system into three generations: 1.0, 2.0 and 3.0 according to the intergenerational evolution described by Melanie Swann. Among them, 1.0 supports decentralized trading and payment systems, 2.0 supports industry applications through smart contracts, and 3.0 supports decentralized social systems. Bitcoin and Chain should belong to the blockchain 1.0 system, while Ethereum and Fabric are blockchain 2.0 systems. There is currently no successful blockchain 3.0 system, but there is one unsuccessful attempt, which is the famous The DAO . The fourth is that according to the core data structure, it is divided into two factions: blockchain and distributed ledger. The blockchain school really implements a chain of blocks as the core data structure in the system, while the distributed ledger school only absorbs the spirit of the blockchain and does not really use a blockchain as the core data structure. , or although it is temporarily used, it is stated that the Zhuangwu blockchain is intended to be a distributed ledger. If time and opportunity come together, it may not be impossible to replace it. Mainstream blockchain technology platforms understand the division of schools, but they can still only be used to point out the country and brag. To start, there must be an entry point. It is said that there are thousands of blockchain currencies, but there are only dozens of technology platforms worth paying attention to. If you want to enter the field of blockchain development, lay a good foundation, practice good skills, and get a few good ones. offer, there are only a handful of platforms worthy of in-depth study and study. The first, of course, is Bitcoin. Bitcoin, as the first and by far the most successful and important model project of the blockchain, has been online for more than eight years without any serious security or safety issues.Operation and maintenance incidents, its stability and power can be regarded as a model of contemporary software systems. Bitcoin Core is an open source software with high code quality and good documentation. From the perspective of learning blockchain principles and mastering core technologies, Bitcoin Core is the best entry point to learn authentic blockchain technology. . Of course, Bitcoin Core is written in C++, and uses some C++11 and Boost library mechanisms, which puts higher requirements on learners' C++ level. Another advantage of learning Bitcoin platform development is that you can connect with the prosperous Bitcoin technology community. There are currently many people working on improving and upgrading Bitcoin. The more people there are, the more power there is. Newer ideas and technologies such as Segregated Verification, Lightning Network, and Sidechains have all taken the lead in being implemented in the Bitcoin community. For example, Blockstream, the main leader of sidechain technology, is led by crypto currency veteran Adam Back, and Blockstream is one of the largest contributors to Bitcoin Core, so some sidechain-related technologies are the most discussed in the Bitcoin community. However, there is great controversy as to whether Bitcoin, as a typical blockchain 1.0 system, is the best technical platform to support other types of blockchain applications. In addition, not everyone has the ability and necessity to be proficient in the underlying technology of blockchain. So for those who are eager to rush into the blockchain field to do (quān) things (qián), the more straightforward learning goals may be Ethereum and Hyperledger Fabric. Smart contract development using Solidity on Ethereum is the easiest way to get into blockchain development, bar none. Ethereum's ideals are very grand. Because it is equipped with a powerful Turing-complete smart contract virtual machine, it can become the mother platform of all blockchain projects and is the big turtle that carries the entire blockchain world. Developing a cryptocurrency similar to Bitcoin on Ethereum is an out-and-out small goal. Generally, experienced developers can get started with the guidance of the documentation in half a day to a day. The question is, what happens after you get started? Can you conquer the world just by writing Solidity? This is highly doubtful. We can also say the other way around, if Ethereum + Solidity is the ultimate solution for blockchain, then why are there so many blockchain technology schools? In particular, Ethereum does not seem to have left a way out for giant centralized organizations in the real world. This completely uncompromising revolutionary attitude may also become an obstacle to the promotion of Ethereum. The current development of the Ethereum project is not going well. A more prominent problem is that there are too many projects and power is dispersed, resulting in uneven project quality. But despite this, compared with other blockchain 2.0 platforms, the development environment provided by Ethereum is the simplest and most complete. It is absolutely necessary for people who are new to blockchain to learn Ethereum to establish the most "authentic" understanding of blockchain and smart contracts. The third branch of the mainstream blockchain technology platform is Fabric.Hyperledger's first and most well-known incubation project. Fabric first came from IBM's Open Blockchain project. By November 2015, IBM handed over the 44,000 lines of Go language code that had been developed to the Linux Foundation and incorporated it into the Hyperledger project. During a hackathon in March 2016, Blockstream and DAH merged their respective codes into Open Blockchain, which was later renamed Fabric. So far, Fabric and Sawtooth Lake provided by Intel are listed as the first-level incubation projects of Hyperledger, but the former has received far more attention than the latter. From a technical perspective, Fabric has a good idea, and its focus is to meet the commercial needs of enterprises, such as solving transaction volume issues. As we all know, Bitcoin’s biggest shortcoming is its upper limit of 7 transactions per second, which is completely unable to meet practical needs. Fabric's goal is to achieve 100,000 transactions per second, which is close to the instantaneous peak of the Double Eleven transaction volume that just passed, and can fully meet industry-level applications under normal conditions. Fabric is developed in Go language and also provides APIs in multiple languages. It is particularly worth mentioning that Fabric makes full use of container technology. For example, its smart contracts run in containers. This is also a benefit that Go language brings to Fabric, because the static compilation and deployment characteristics of Go language are very suitable for developing programs in containers. Fabric also has some features, such as its membership service that can set up node access review, which is a typical alliance chain feature. Another example is that its consensus algorithm is customizable. The shortcoming of Fabric is that the system is relatively complex. Although it has documentation, it is difficult for developers who lack experience to learn it. However, because of its clear positioning and catering to the mentality of many companies, many institutions are already secretly developing alliance chain projects in the industry based on Fabric.

『撒』 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, which can be a public ledger (visible by anyone) or a permissioned network (visible only by those authorized), 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 kind of data that records transactionsStructure reflects the flow of funds in 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 ultimately generates a unified hash value of all transaction information in the block. Any change in transaction information in the block will cause Merkle tree changes.
Core technology 4. Asymmetric encryption algorithm:
Asymmetric encryption algorithm is a key secret method that requires two keys: public key and private key. The public key and the private key are a pair. If the public key is used to encrypt data, only the corresponding private key can be used to decrypt it, thereby obtaining the corresponding data value; if the private key is used to sign the data, then only the corresponding public key can be used to sign the data. In order to verify the signature, the sender of the verification information is the holder of the private key.
Because encryption and decryption use two different keys, this algorithm is called an asymmetric encryption algorithm, while symmetric encryption uses the same key in the encryption and decryption processes.
Blockchain technology----network layer: realize the decentralization of accounting nodes
Core technology 5. P2P network:
P2P network (peer-to-peer network),Also known as point-to-point technology, it is an Internet system that does not have a central server and 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, in the PeerCoin PoS mechanism, the Bitcoin with the longest chain age has a greater chance of obtaining accounting rights. NXT and Blackcoin use a formula to predict the next accounting node. The more tokens you own, the greater the probability of being selected as an accounting node. In the future, Ethereum will also switch from the current PoW mechanism to a PoS mechanism. Judging from the information currently available, Ethereum's PoS mechanism will use nodes to place bets on the next block. The winner of the bet will receive an additional Ethereum currency award. Those who do not win will be deducted Ether coins to reach consensus on the next block.
DPoS (DelegatedProof-Of-Stake, share authorization certificate): DPoS is easy to understand and is similar to the modern corporate board of directors system. The DPoS mechanism adopted by BitShares is that shareholders vote to select a certain number of witnesses. Each witness has two seconds of authority to generate blocks in order. If the witness cannot generate a block within the given time slice, Block generation permission transferGive 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 programmed rules and logic that respond to scenarios. Implemented by decentralized, trusted shared script code deployed on the blockchain. 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.

『8』What does the core technology of blockchain include?

First of all, we can take a look at the official website of blockchain technologyexplain. 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.

『九』 Which companies are relatively mature in developing blockchain technology?

Shandong Bianke Information Technology Co., Ltd. is a software development company with excellent technology.

[Blockchain Exchange]

Blockchain technology application research and development, exchange wallet system app development Blockchain technology is actually a new type of Internet. Why is it said to be a subversion of the Internet? Because the Internet solves the problem of information transmission, and the blockchain solves the problem of value transmission. Yuanzhongrui Blockchain System Develops Blockchain There are many value transfers, such as: distributed ledgers, decentralized trust, smart contracts, etc. ThenSo what kind of society will it build in the future?

The answer is: a distributed business and self-disciplined society. The first characteristic of blockchain is decentralization; no third-party intervention is required to realize person-to-person, point-to-point transactions and interactions.

Second, the information cannot be tampered with; once the data information is written into the block, it cannot be changed or revoked.

Third, openness and transparency; within a very short period of time, the block information will be copied to all blocks in the network to achieve data synchronization across the entire network, and each node can trace back all past transactions of both parties. information.

Fourth, collective maintenance; in the entire blockchain network, all roles jointly maintain the reliability and security of the entire blockchain information.

Fifth, reliable database; only by mastering 51% of the nodes in the entire system can the blockchain information be tampered with. This is obviously impossible because there are many participants in the entire system and so many nodes are mastered. The cost is extremely high and it is impossible to achieve.

The characteristics of blockchain bring great opportunities to the financial industry. Using it to transform internal application scenarios in the industry can bring three main benefits:

< P>1) Reduce costs: Communication costs: Centralized trading markets generally require the participation and coordination of multiple parties such as central settlement systems, securities companies, exchanges, and banks. The coordination costs are very high. Through the signature encryption next to the blockchain source, etc. Technology allows information to be shared and reduces coordination costs; operating costs: reducing labor and paper vouchers, improving automation through smart contracts, and centralized coordination also bring very high operating costs.

2) Improve efficiency: The settlement cycle is very fast. When the financial transactions realized through blockchain technology are confirmed, it is actually a settlement process that combines clearing, settlement and auditing. The openness, transparency and non-tamperability of the blockchain can save traces of operations, allow supervision records and audit traces to be retained, and facilitate supervision and auditing.

3) Reduce risk: The transaction confirmation on the chain completes the clearing and calculation, greatly reducing the transaction risk. Blockchain technology application research and development, exchange wallet system app development

『Shi』 What are 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 blockchain 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 Records the main chain or part of the main chain.

Each block consists of blocksThe block header is composed of a 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 includes the current version number, the previous block address, and a timestamp (recording the time when the block was generated. Accurate to the second), random number (recording the answer value to the mathematical problem related to decrypting the block), the target hash value of the current block, the root value of the Merkle number source and other information. From a structural point of view, most of the 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 The principle of the code is a one-way hash function based on cryptography. This function is easy to verify, but difficult to interpret. The industry usually expresses it in the form of y=hash(x). This hash function implements the hash operation of x. Value y.

Commonly used hash algorithms include MD5, SHA-1, SHA-256, SHA-384, SHA-512, etc. Taking the SHA256 algorithm as an example, if you input any data into SHA256, you will get 256 Bit Hash value (hash value). Its characteristics: the same data input will get the same result. A slight change in the input data (for example, 1 becomes 0) will get a completely different result. The result is measured. Forward calculation (data calculation The corresponding Hash value) is very simple. Reverse calculation is extremely difficult and is considered impossible under current scientific and technological conditions.

Core technology 3. Merkle tree:

Merkle tree is A hash binary tree can quickly verify the integrity of large-scale data. In the blockchain network, Merkle V Dan Lu Xing Wei Wei Hui Zai Pan⒌ Mou Xi Ji Ceng Mou_erkle trees.

Core technology 4. Asymmetric encryption algorithm:

Asymmetric encryption algorithm is the secret of the key The method requires a key and a key. 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 The public key verifies the signature and verifies 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 The same key is used in the decryption process.

Blockchain mitigation technology - network layer: achieving 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 a user group exchanging information. Unlike a central network system with a central server, each client in the peer-to-peer network is a node , also has the function of a server. 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