Blockchain public chain has several elements

1.

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

2. 1. The so-called blockchain technology, also known as the distributed ledger technology, is an Internet database technology, which is characterized by decentralization, openness and transparency, so that everyone can participate in database records
2. Blockchain is an innovative application mode of distributed data storage, point-to-point transmission, consensus mechanism, encryption algorithm and other computer technologies in the Internet era. In recent years, the development and application of blockchain is of great significance to technological innovation and instrial revolution. This experience introces the relevant knowledge of blockchain technology
3. Blockchain is a distributed ledger, which can contain financial and / or non-financial transactions. It can be replicated (distributed) on multiple systems in almost real time through peer-to-peer network. Each participant "owns" the same ledger and gets updated when adding any transaction. Each participant helps to determine the inherent "invariance" of all existing records, Using cryptography and digital signature to prove identity, authenticity and enforce read / write access, there is a mechanism that makes it difficult to change history, and it is easy to detect someone trying to change it.

3. The analysis elements of jinwowo network are as follows:

1-contains a distributed database

2-distributed database is the physical carrier of blockchain, blockchain is the logical carrier of transaction, all core nodes should contain full copies of the blockchain data

3-blockchain serializes blocks according to time, And blockchain is the only body of the whole network transaction data

4-blockchain is only effective for addition, but not for other operations

5-public and private key verification based on asymmetric encryption

6-accounting node requires that Byzantine general problem can be solved / avoided

7-consensus progress is evolutionarily stable, That is, in the face of a certain amount of contradictions between different nodes, the data will not collapse

8-consensus process can solve the problem of double spending

4. The following points are the characteristics of the blockchain summarized by jinwowo group:

1 - Decentralization: because the blockchain relies on each node to achieve system maintenance and ensure the authenticity of information transmission, it is based on distributed data storage without centralized management by a certain center, Therefore, the attack and tampering of a node will not affect the healthy operation of the whole network

2-DE Trust: the establishment of a connection between any two nodes does not need to trust each other's identity, and the data exchange between the two sides does not need the basis of mutual trust. Since all nodes in the network can act as "supervisors", there is no need to worry about fraud

3 - extensible: blockchain is an underlying open source technology, on which various kinds of extension, decentralized and distrusted applications can be realized<

4 - anonymization: the two sides of data exchange can be anonymous, and the nodes in the network can exchange data without knowing each other's identity and personal information

5 - Security and reliability: because the activities between any nodes are supervised by the whole network, and the database adopts distributed storage, for hackers, first, they can't disguise and cheat, Second, we can't control the network only by conquering a node.

5.

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

6. The public chain, as the name suggests, has great inclusiveness and fairness. The better the public chain project does in these two aspects, the more prominent it will be. At present, many public chains sacrifice fairness in order to speed up the transaction, which is not optimistic. There is a project called Fanta network. Their DSC technology claims to be safe, democratic and fair, which deserves long-term attention. However, their code will not be open source until the end of the year, and the progress needs to be accelerated

7. 1-contains a distributed database

2-The distributed database is the physical carrier of the blockchain, and the blockchain is the logical carrier of the transaction. All core nodes should contain the full of the blockchain data

3-The blockchain serializes the blocks according to time, and the blockchain is the only body of the whole network transaction data

4-The blockchain is only effective for adding, Invalid for other operations

5-public-private key verification based on asymmetric encryption

6-accounting node requires that Byzantine general problem can be solved / avoided

7-consensus progress is evolutionarily stable, that is, it will not collapse in the face of a certain amount of contradictory data of different nodes

8-consensus process can solve the problem of double spending

five characteristics of blockchain:
decentralized
e to the use of Distributed Accounting and storage, there is no centralized hardware or management organization, the rights and obligations of any node are equal, and the data blocks in the system are jointly maintained by the nodes with maintenance function in the whole system
thanks to the decentralization of blockchain, bitcoin also has the characteristics of decentralization [6]
openness
the system is open, in addition to the private information of all parties to the transaction is encrypted, the data of the blockchain is open to all, and anyone can query the blockchain data and develop related applications through the open interface, so the information of the whole system is highly transparent
autonomy
blockchain adopts consensus based specifications and Protocols (such as a set of open and transparent algorithms) to enable all nodes in the whole system to exchange data freely and safely in a de trusted environment, so that the trust in "people" is changed into the trust in machines, and any human intervention does not work
information cannot be tampered with
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, the modification of the database on a single node is invalid, so the data stability and reliability of the blockchain are extremely high<
anonymity
since the exchange between nodes follows a fixed algorithm, their data interaction does not need trust (the program rules in the blockchain will judge whether the activity is effective by themselves), so the counterparties do not need to let the counterparties generate their own trust by disclosing their identities, which is very helpful for credit accumulation.

8.

According to reports, blockchain has the advantages of decentralization, distrust and tamper proof

compared with the Internet, the blockchain network conceived by Cosmos not only realizes information interaction, but also realizes the transmission of asset value. Through the IBC cross chain protocol, the token can be transferred across the chain between the blockchains based on Cosmos' tendermint core. For the public chains based on POW consensus mechanism like Ethereum, pegged zone can be used to bridge

Article source: bit110 network

9. The first thing that Java needs to pay attention to in developing blockchain is the hierarchical relationship. Once it's confused, it's difficult to sort out
the difference between blockchain and ordinary mall is that it adds the function of virtual currency. You can see the interface and docking method of virtual currency at other times to avoid mistakes

10. The characteristics of the public chain in jinwowo network analysis blockchain technology are as follows:
(1) running on the Internet

(2) completely distributed< (3) the number of data nodes is changeable and unpredictable< (4) the data is public< (5) anyone can participate anonymously

(6) the operation and maintenance cost is high and depends on the reward mechanism< (7) the transaction speed is slow.