Blockchain alliance chain disconnection
blockchain includes public blockchain, joint (instry) blockchain and private blockchain. Public chain point-to-point e-cash system: bitcoin, smart contract and decentralized application platform: Ethereum
blockchain is a new application mode of distributed data storage, point-to-point transmission, consensus mechanism, encryption algorithm and other computer technologies
blockchain is an important concept of bitcoin. In essence, it is a decentralized database. At the same time, as the underlying technology of bitcoin, it is a series of data blocks generated by using cryptographic methods. Each data block contains a batch of bitcoin network transaction information, Used to verify the validity of its information (anti-counterfeiting) and generate the next block
extended data
according to the different degree of blockchain network centralization, three kinds of blockchains under different application scenarios are differentiated:
1. The blockchain with the whole network open and without user authorization mechanism is called public chain
2. The authorized nodes are allowed to join the network, and the information can be viewed according to the authority. It is often used in the inter agency blockchain, which is called alliance chain or instry chain
3. All the nodes in the network are in the hands of one organization, which is called private chain
alliance chain and private chain are also called licensing chain, and public chain is called non licensing chain
blockchain features
1, decentralization. Blockchain technology does not rely on additional third-party management institutions or hardware facilities, and there is no central control. In addition to the self-contained blockchain itself, each node realizes information self verification, transmission and management through distributed accounting and storage. Decentralization is the most prominent and essential feature of blockchain
2. Openness. Blockchain technology is based on open source. In addition to the private information of all parties involved in the transaction is encrypted, the data of blockchain is open to everyone. Anyone can query blockchain data and develop related applications through the open interface, so the information of the whole system is highly transparent
3. Independence. Based on consensus specifications and Protocols (similar to various mathematical algorithms such as hash algorithm used by bitcoin), the whole blockchain system does not rely on other third parties, and all nodes can automatically and safely verify and exchange data in the system without any human intervention
4. Safety. As long as 51% of all data nodes cannot be controlled, the network data cannot be arbitrarily manipulated and modified, which makes the blockchain itself relatively safe and avoids subjective and artificial data changes
5. Anonymity. Unless there are legal requirements, technically speaking, the identity information of each block node does not need to be disclosed or verified, and the information can be transferred anonymously
in the early stage of the development of the blockchain instry, many enterprises and institutions formed a blockchain alliance to share the research results of blockchain technology and seek wider application of blockchain technology
in the past two years, blockchain alliances have emerged. As of July 2017, there are R3 composed of more than 40 international banks, hyperledger initiated by Linux foundation, Zhongguancun blockchain Instry Alliance located in the core hinterland of China's Internet, China ledger alliance jointly initiated by 11 institutions, gold chain alliance jointly established by 25 financial institutions, and so on Russia's blockchain alliance, known as "Russian version R3", seeks to combine with micro finance, Qianhai international blockchain ecosphere alliance led by Shenzhen Qianhai administration, and Lujiazui blockchain Financial Development Alliance in Lujiazui
many organizations and talents join to promote the vigorous development of blockchain.
Public chain, also known as "public chain", refers to the blockchain that anyone in the world can enter the system at any time to read data, send confirmatory transactions and compete for bookkeeping. The public chain is generally considered to be "completely decentralized", because no indivial or institution can control or tamper with the reading and writing of data in it. In terms of application, blockchain public chain mainly includes bitcoin, Ethereum, super ledger, most counterfeit currencies and smart contracts. The ancestor of blockchain public chain is bitcoin blockchain, which has the following characteristics:
1, open source code
upload the code to GitHub, and everyone can get complete blockchain data by downloading, Accept the test of the public
2, complete decentralization
anyone can become a node, each node is open, everyone can participate in the calculation of the blockchain, any node is not permanent, but phased, and any center is not mandatory for nodes. Anyone can read and send transactions, and transactions can be effectively confirmed on the blockchain. Anyone can participate in the consensus process. The consensus process determines whether a block can be added to the blockchain and the exact current state. Everyone can get financial reward from it, which is proportional to their contribution to the consensus process. These public chains are generally considered to be "completely decentralized"
3. Developing decentralized applications
through this public chain, developers can easily develop centralized applications. Public chain can protect the rights and interests of users from the influence of program developers

This is two different concepts. According to different standards, blockchain can be classified into three categories:
& # 8195 8195; 1) According to the network scope of blockchain, it can be divided into public chain, private chain and alliance chain
8195; 2) According to the docking type of blockchain, it is divided into single chain, side chain and interconnection chain
8195; 3) According to the display environment of blockchain deployment, it can be divided into main chain and test chain
the main chain can be understood as a formal online and independent blockchain network, while the public chain refers to a blockchain that can be read by anyone, can send transactions and can be effectively confirmed by anyone, and can participate in its consensus process

public chain: open to all, anyone can participate
private chain: open to indivial indivials or entities
alliance chain: open to specific organizations
Blockchain is strictly divided into three types: public chain, private chain and alliance chain. The core difference between these three types of blockchains is the degree of openness or decentralization of access rights. Generally speaking, the higher the degree of decentralization, trust and security, the lower the transaction efficiency
generally speaking, each type of blockchain has its own specific mode and value, which is better than others. As long as the demand is solved, the blockchain is valuable

1. Data layer: encapsulates the underlying data block and related data encryption and timestamp technologies
2. Network layer: it includes distributed networking mechanism, data dissemination mechanism and data verification mechanism
3. Consensus layer: it mainly encapsulates various consensus algorithms of network nodes
4. Contract layer: it mainly encapsulates all kinds of scripts, algorithms and smart contracts, which is the basis of the programmable characteristics of blockchain
5. Application layer: encapsulates various application scenarios and cases of blockchain.
alliance chain refers to a blockchain with several institutions participating in the management. Each institution runs one or more nodes, and the data only allows different institutions in the system to read, write and send transactions, and record transaction data together<
technical characteristics of alliance chain
1.
low cost operation and maintenance
2.
high transaction speed and good scalability
3.
alliance maintenance,
is more reliable than private chain
It can be understood as the LAN of Internet bar H2 >
a few people use it by themselves, more people use it, and more open people still need license, that is, the alliance chain
there is no need for license at all. Anyone can use the public chain
