The concept of blockchain is put forward by

1.

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. It is essentially 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 the information of a bitcoin network transaction, Used to verify the validity of its information (anti-counterfeiting) and generate the next block

some areas where blockchain can be used can be as follows:

& ᦇ 9642; Smart contract; Securities trading; E-commerce; Internet of things; Social communication; File storage; Proof of existence; Authentication

&9642; Equity crowdfunding

we can compare the development of blockchain with the development of the Internet itself. In the future, something called finance Internet will be formed on the Internet. This thing is based on blockchain, and its precursor is bitcoin, that is, traditional finance starts from private chain and instry chain (LAN), bitcoin series starts from public chain (WAN), They all express the same concept - digital asset, and finally converge to an intermediate equilibrium point

The evolution mode of

blockchain is as follows:

& 9642; Blockchain 1.0 digital currency; Blockchain 2.0 digital assets and smart contracts; Blockchain 3.0: implementation of distributed applications in various instries

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. Satoshi Nakamoto, who calls himself Japanese American, is the creator of bitcoin protocol and its related software bitcoin QT, but his real identity is unknown. In 2008, Nakamoto published a paper called "bitcoin: a peer-to-peer electronic cash system", which describes an electronic currency and its algorithm called "bitcoin". In 2009, he released the first bitcoin software and officially launched the bitcoin financial system. In 2010, he graally faded out and handed over the project to other members of the bitcoin community. Nakamoto is believed to hold about one million bitcoins.

4. Blockchain is a decentralized ledger, which can keep the actual records of all transactions. For example, when using this technology to manage remittances, the ledger looks like a bank statement, recording information such as amount, date, sender and recipient. The data structure contains encryption technology, which allows each member of the network to manage the ledger safely without centralized execution. The lack of central authority in the system is one of the most influential innovations in blockchain technology
once the information is recorded in the blockchain, it will become permanent and impossible to change or delete. If a user wants to create a new entry (called a block) to the ledger, other users in the network must verify the information they propose to add. Each computer on the network (called a "node") compares the submitted information with the existing ledger. If most nodes can verify the accuracy of the new block of information, it is allowed to become a permanent part of the ledger. Because the blockchain network is composed of computers in multiple locations, even if a certain network is destroyed, the security of the whole data will not be affected
to understand the working principle of blockchain technology, we must first know the data type of each block in Dimon. Except for transaction data, all blocks contain digital fingerprints called hashes. Each unique hash is generated based on the information within the block, so if the data is changed in any way, the hash will change automatically. This cryptography is the key to decentralized authority of blockchain. The new block also contains the imprint of the hash assigned to the previous block and the chain of entries being audited. If the user attempts to tamper with the block data, the hash cannot be authenticated and the entry is rejected.