What the hell is blockchain
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)
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 robustnesstrustworthiness: 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
blockchain is a system in which everyone participates and keeps accounts together. Each node in the system can participate in bookkeeping. The node with bookkeeping right writes the transaction to the account book, and sends it to other nodes in the system for verification and record. After writing, the data cannot be tampered with. Each node has a complete account book, and anyone can view the data in the account book
What's the real use of blockchain? Let's give you a chestnut to explain:
the concentric mutual help launched by ABZ Financial Technology Co., Ltd., a blockchain start-up company, combines open source code with practical application to realize the deep matching between blockchain technology and network mutual help. First of all, all capital flows are open and transparent, and can not be forged or tampered with. Every user can exercise the right of supervision. Secondly, the transfer of all funds can only be carried out in accordance with the open smart contract, and there is no legal person for misappropriation and intervention. Finally, each user's personal sensitive information will be highly encrypted, and no one else can access it. Blockchain can not be tampered with, but can be associated. The application of big data can improve the operation efficiency of blockchain and achieve the purpose of optimizing procts.
blockchain technology is considered to be the next generation of disruptive core technology after steam engine, power and Internet. If the steam engine has released people's proctivity, the power has solved people's basic living needs, and the Internet has completely changed the way of information transmission, then the blockchain, as a machine for building trust, may completely change the way of value transmission of the whole human society
first, the essence of blockchain is a distributed public ledger
take a popular example to explain that Mr. w's family, including Mr. W, Mrs. W, Mr. w's grandfather and Mrs. w's grandmother, all record their expenses in their respective books. Because Mr. w's family doesn't trust each other. Mr. W is diligent in raising his wife every month, but Mrs. w may receive 1000 yuan, but she receives 100 yuan. Isn't that a big loss
how to solve this problem with blockchain
if Mr. w gives Mrs. w $1000 one day, he just shouts at the whole family that Mr. w gives Mrs. w $1000. Please write down "Mr. w gives Mrs. w $1000" on their respective account books
so everyone in Mr. w's family becomes a node, and every transaction of Mr. w's family is recorded by everyone (each node)
every night who washes the dishes (proof of workload) can settle the bill in the public ledger, and there is a reward for washing the dishes. A new transaction must be added to the universally recognized ledger of the previous day, and other people will also participate in verifying the transactions of the day
Second, it seems very simple, but blockchain may bring revolutionary changes to human society
1. Machine trust
machine trust is actually trust without trust. For the first time in human history, a large-scale cooperation network unprecedented on earth can be established at near zero cost, which is bound to be a great mass movement
2. Value transfer
the emergence of the Internet has made the means of information dissemination achieve a leap, and information has realized efficient flow, but the efficiency of Internet value transfer is still very slow. At present, e-money on the Internet is still the traditional paper money in essence, and transnational payment is still a big problem
the birth of blockchain is the beginning of human value transmission network. It will enable people to transfer value as conveniently and cheaply as information on the Internet, which can be expressed as capital, assets or other forms
3. Smart contract
smart contract can replace all paper contracts, and more importantly, blockchain can perfectly connect the physical world and virtual world. The perfect combination of blockchain, Internet of things and artificial intelligence makes the imagination more huge
the blockchain itself is actually a super platform. The commercial characteristics of building machine trust, value transfer and smart contract on the blockchain are: ① close to zero trust cost. ② The marginal cost of constructing and trading assets tends to zero
so Mark Anderson, a web browser pioneer, said: in 20 years' time, we will talk about blockchain as we talk about the Internet today.