What is Ali 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
The 
blockchain is a technical solution to collectively maintain a reliable database through centralization and distrust in the past
generally speaking, blockchain technology refers to a way for the whole people to participate in bookkeeping. There is a database behind all the systems. You can think of the database as a big ledger. So it's very important who keeps this account book. At present, whose system will keep accounts, wechat's account book is Tencent's account book, and Taobao's account book is Ali's account book. But now in the blockchain system, everyone in the system can have the opportunity to participate in bookkeeping. If there is any data change in a certain period of time, everyone in the system can conct bookkeeping. The system will judge the person who has the fastest and best bookkeeping in this period, write the content of his records into the account book, and send the content of the account book to all other people in the system for backup. In this way, everyone in the system has a complete account book. This way, we call it blockchain technology
now, blockchain technology will be very popular, especially in the financial sector. Ant finance, laikelib, Wanda, Ping'an and Minsheng have tried blockchain projects one after another, and European crowdfunding is in the forefront of using blockchain technology. The most successful case is digital currency
what is blockchain? Blockchain technology is a way for the whole people to participate in bookkeeping. There is a database behind all the systems. You can think of the database as a big ledger. So it's very important who keeps this account book. At present, whose system will keep accounts, wechat's account book is Tencent's account book, and Taobao's account book is Ali's account book. But now in the blockchain system, everyone in the system can have the opportunity to participate in bookkeeping. If there is any data change in a certain period of time, everyone in the system can conct bookkeeping. The system will judge the person who has the fastest and best bookkeeping in this period, write the content of his records into the account book, and send the content of the account book to all other people in the system for backup. In this way, everyone in the system has a complete account book. This way, we call it blockchain technology
what is blockchain? For example, in our daily online shopping, the money paid after placing an order for the selected goods will first be paid to the third-party payment platform, and the third-party payment platform will only pay the money to the seller's account after the seller delivers the goods to the buyer to confirm the receipt
when a transaction occurs between the buyer and the seller, the system will broadcast the transaction information between them. The person who receives the message will record the transaction after confirming that the message is correct, that is, the person who receives the message has made a data backup for the transaction
just like Zhang Ergou bought an inflatable doll on the Internet, the system would hold a loudspeaker and shout in the village: "Zhang Ergou bought an inflatable doll"“ After hearing the broadcast, the villagers took out a small notebook and wrote it down. Zhang Ergou bought an inflatable doll. Here, the recorded information is like a data backup for this transaction. Back to the current online shopping, if Zhang Ergou's order problems, Alipay system failure can not record this transaction, then Li Goudan's money is not white. On the blockchain, if there is a problem with the order, because in the early stage, the system broadcast everywhere that Zhang Ergou bought an inflatable doll with a loudspeaker, so countless people recorded the transaction information, and there would be no system failure to record the transaction records
what is blockchain? At present, blockchain technology is very popular, especially in the financial sector. Ant finance, LETV finance, Wanda, Ping'an and Minsheng have successively tested blockchain projects, and eurocrowdfunding is in the forefront of using blockchain technology
blockchain is a large-scale and decentralized economic organization mode realized by a group of technologies
bitcoin is a practical embodiment of blockchain technology, which is more accurate than the former
in fact, whether it's blockchain or bitcoin, people are more concerned about the coin itself, which coin makes more money and how to join it
what is blockchain? Blockchain has attracted wide attention because it has changed the original economic organization mode in many fields. For example, in the process of currency issuance and circulation, cryptocurrency makes the core role of the banking system decline, and the organization mode among the central bank, commercial banks and users has changed significantly; In Ethereum erc20 token system, blockchain has completely changed the organization mode among securities issuers, participants at all levels and regulators. Although it brings some problems, it also improves the efficiency of securities issuance and circulation
people are now exploring the application of blockchain in various fields of economy. In essence, they are looking for new ways to use blockchain to adjust or innovate the original economic organization mode of enterprises, instries and regions, and to rece costs and improve revenue. As an economic organization mode, blockchain can be extended downward to its implementation technology, and upward to its impact on social organization and social consciousness, which makes it easier to understand the complex social impact brought by blockchain.
Ma Yun: I want to know what bitcoin can bring to the society
at the two sessions, Ma Yun... Oh, sorry, Comrade Ma Yun who doesn't want to wear a red hat didn't attend the two sessions
In November 2017, Alibaba, ant financial services and xiong'an signed a strategic cooperation agreement to build a "digital xiong'an blockchain implementation platform". At present, ant financial services has provided blockchain landing application technology in the rental field in xiong'an. It can be said that xiong'an has become the first pilot field of Ali in the overall implementation project of blockchain technology