Blockchain double chain

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.

The strict definition of blockchain refers to the distributed database technology that multiple nodes in peer-to-peer network jointly maintain a continuously growing list ledger constructed by time stamp and orderly record data blocks through consensus mechanism based on cryptography technology. This technical solution allows any number of nodes in the participating system to calculate and record all the information exchange data in the system in a period of time to a data block through cryptography algorithm, and generate the fingerprint of the data block for linking the next data block and checking. All participating nodes in the system jointly determine whether the record is true

blockchain is a technical solution similar to NoSQL (non relational database). It is not a specific technology, and can be implemented through many programming languages and architectures. There are many ways to realize blockchain, including pow (proof of work), POS (proof of stake), dpos (delegate proof of stake), etc

the concept of blockchain was first proposed in the paper "bitcoin: a peer-to-peer electronic cash system" by indivials (or groups) who call themselves Satoshi Nakamoto. Therefore, bitcoin can be regarded as the first application of blockchain in the field of financial payment

< H2 > [popular explanation]

no matter how big the system or how small the website is, there is a database behind it. So who will maintain this database? In general, who is responsible for the operation of the network or system, then who is responsible for the maintenance. If it is wechat database, it must be maintained by Tencent team, and Taobao database is maintained by Alibaba team. We must think that this way is natural, but blockchain technology is not

if we think of the database as a book, for example, Alipay is a typical account book. Any change of data is bookkeeping. We can think of database maintenance as a very simple way of accounting. In the world of blockchain, everyone in the blockchain system has the opportunity to participate in bookkeeping. The system will select the fastest and best bookkeeper in a period of time, maybe within ten seconds or ten minutes. The bookkeeper will record the changes of the database and the account book in a block. We can think of this block as a page. After the system confirms that the records are correct, the system will record the changes of the database and the account book in a block, It will link the fingerprint of the past account book to this paper, and then send this paper to everyone else in the whole system. Then, over and over again, the system will look for the next person with fast and good bookkeeping, and everyone else in the system will get a of the whole ledger. This means that everyone as like as two peas in the system is called Blockchain. It is also called distributed account technology. P>

as like as two peas (computer) have identical accounting books, and everyone has the same rights, they will not collapse e to the loss of contact or downtime of a single person. As like as two peas, the data is transparent and everyone can see what changes are in every account. Its very interesting feature is that the data can't be tampered with. Because the system will automatically compare, it will think that the same number of books with the largest number are real books, and a small number of books with different numbers are false books. In this case, it's meaningless for anyone to tamper with his own account book, because unless you can tamper with most nodes in the whole system. If there are only five or ten nodes in the whole system, it may be easy to do so. However, if there are tens of thousands or even hundreds of thousands of nodes and they are distributed in any corner of the Internet, unless someone can control most computers in the world, it is unlikely to tamper with such a large block chain

< H2 > [elements]

combined with the definition of blockchain, we think that we must have the following four elements to be called public blockchain technology. If we only have the first three elements, we will consider it as private blockchain Technology (private chain)

1, peer-to-peer network (power equivalence, physical point-to-point connection)

2, verifiable data structure (verifiable PKC system, non tampering database)

3, distributed consensus mechanism (Solving Byzantine general problem, solving double payment)

4 Game design of Nash equilibrium (cooperation is the strategy of evolutionary stability)

< H2 > [Characteristics]

combined with the definition of blockchain, blockchain will realize four main characteristics: decentralized, trustless, collective maintenance and reliable database. And the other two will be derived from the four characteristics  Features: open source  Privacy. If a system does not have these characteristics, it can not be regarded as an application based on blockchain technology

Decentralized: there is no centralized hardware or management organization in the whole network. The rights and obligations of any node are equal, and the damage or loss of any node will not affect the operation of the whole system. Therefore, it can also be considered that the blockchain system has excellent robustness

trustworthiness: there is no need to trust each other when participating in the data exchange between each node in the whole system. The operation rules of the whole system are open and transparent, and all data contents are also open. Therefore, within the specified rule range and time range of the system, nodes cannot and cannot cheat other nodes

collective maintenance: the data blocks in the system are maintained by all the nodes with maintenance function in the whole system, and these nodes with maintenance function can be participated by anyone

reliable database: the whole system will enable each participating node to obtain a of the complete database in the form of sub databases. Unless more than 51% of the nodes in the whole system can be controlled at the same time, the modification of the database on a single node is invalid, and the data content on other nodes cannot be affected. Therefore, the more nodes and computing power in the system, the higher the data security in the system

Open Source: since the operation rules of the whole system must be open and transparent, the whole system must be open source for the program

Privacy Protection: since there is no need to trust each other between nodes, there is no need to disclose the identity between nodes, and the privacy of each participating node in the system is protected

3. Double chain structure blockchain Technology: mainly for the single chain to make an explanation, because the single chain structure can not effectively realize the application of the entity, can not effectively realize the application of the value management of human labor time, so give it a second value chain. Double strand structure technology is inspired by DNA structure, and wasian is based on double strand structure blockchain technology

4. How much does it cost to register a company in Shanghai? Many entrepreneurs will probably ask this question. In the era of national entrepreneurship, most people will choose to register the company after they have a project. However, there are two practical problems in front of Shanghai registered company:
first, if there is not much start-up capital in hand, how to raise funds to set up a company with a registered capital of 1 million yuan
Second, we are going to start business at home at the beginning, but we can't complete the instrial and commercial registration of family residence. What should we do< In fact, since March 1, 2014, the state has begun to adjust its policies and implement the system of subscription of registered capital. Even if there is no start-up capital, other methods can be used to register the company. In the new policy, the restrictions on the way, time limit and amount of capital contribution are cancelled. The purpose of the state's move is to encourage entrepreneurship. Even if you don't have any money, you can easily register a company with 1 million yuan in this way. In the future, when you make money, you can supplement the registered capital
What are the fees for registering a company in Shanghai, regardless of the registered capital? Zhihao has sorted out for you the expenses of business registration, seal engraving and tax registration certificate in the process of company registration, as well as the expenses of subsequent business tax declaration, taxpayer and registered address of the company
I. business registration fees. In the national policy, business registration does not need to spend money, free of charge
2. The cost of official seal engraving. A very important step to complete the instrial and commercial registration is to obtain the official seal. The cost of carving the official seal is 50 yuan / set, which is a necessary cost< Third, the cost of tax registration certificate. The fee is free< 4. Fees for Instry license and food hygiene license. If the company needs to apply for these certificates, there may be corresponding expenses< 5. The bank opens the basic account of the company. For bank account opening, the fee charged by each company may vary to a certain extent. The general fee is more than 500 yuan< 6. The cost of purchasing invoice. The company needs to buy tax cards, special printers, billing software and so on. The total cost is about 2000-3000 yuan< 7. If you need to apply for general taxpayer qualification and issue VAT invoice, the cost will be increased. If an enterprise is engaged in import and export trade, there are administrative charges when it goes through the import and export filing proceres, and the cost is about 2000 yuan.
8. If it is entrusted to an agent company, the cost of registering a million companies in Shanghai is not much, but in the process of registering a company, there may be a lot of cumbersome affairs to deal with, In this case, in fact, looking for an agent to complete the registration can save more time and energy. The total agent fee is about 500 yuan
simply speaking, the process of business registration in Shanghai is as follows:
check the name - register online - hand in the business establishment information - get the business license - engrave the seal - do the organization code certificate - do the tax registration certificate - open the basic account (taxpayer)
the detailed steps and cycle are as follows:
1. To approve a company name, it is better to submit 3-5 company names in the preferred order at a time to prevent plicate names. If it is submitted again, the approval time will be longer. The name of the company requires the company name, shareholder name, ID number and capital contribution ratio. 1-3 days
2. After the name is approved, fill in all the delivery materials, make an appointment, and submit the documents to the Administration for Instry and commerce; 7 days
3 and 7 days later, after obtaining the business license, we will handle the tax, code and stamp. 7 days to complete the documents

5. Because it comes from money. Virtual money is bought with real money. So it's also called coin there.