Blockchain Taiji
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
however, it's easy for people with an eye to see why there is no security layer? In fact, several key features of blockchain have already solved the security problem. First, the blockchain uses asymmetric encryption technology. In fact, encryption and decryption are different keys, namely public key and private key. In short, the public key is open to the public, while the private key is absolutely confidential
secondly, distributed bookkeeping is a way for blockchain to store data. It can also be understood as distributed storage, which is consistent with the concept of decentralization. In the form of ledger, there is no central ledger in the network, and the ledger is stored in each node. Each node is not only independent, but also can act as the central node. Therefore, the central node will not be attacked, leading to the loss of core books or data, and the whole network will not be paralyzed
moreover, tamper proof is the basic feature of blockchain. As long as the chain can not be modified, and can not be deleted. If it needs to be changed, based on the principle of transparency and openness, the whole network and all nodes need to be informed. Therefore, under the democratic mechanism, the possibility of tampering with data at will is very low. Therefore, blockchain technology is applied in various instries, such as finance, payment, traceability, games, etc., such as the network "universe", Tencent's "come together to catch the demon", and Zhongan Huanyu blockchain "Dr dragon hunt" are the safe and high-quality procts under the blockchain technology.
Chinese Mahjong: the world's earliest blockchain project
first of all, a initiates an application. I want to play mahjong and set up a mahjong Bureau, which is equivalent to creating a block, and this block will be broadcast to B, C, D, a, B, C, C, C, C, C, D, D, D, D, D, D, D, D, D, D, D, D, D, D, D, D, D, D, D, D, D D...
in the process of playing mahjong, the above four people constantly play cards, which can be understood as mining, through what to mine? Mahjong machine can understand the mineralization machine. These four miners are the so-called miners. These four miners collide from 144 mahjong, and any right card can be Hu card. We can understand the 144 mahjong as a series of hash values (numbers). The process of Hu card is called computational power. Until Hu card, it means that the right hash value is collided and you can get a reward, Each person will pay the corresponding chips to C and put them in the blockchain. The reward is bitcoin or other virtual coins
Why do the other three people take the initiative to reward C? That's because these people have automatically reached a consensus that C has indeed won, and everyone has recorded the account, including the family members who are sitting next to buy horses. It's not good to deny it, otherwise when it comes out that the character is not good, no one will play with him again. After all, the circle is very important
when we reached a consensus, we didn't see any intermediary or third party judging that C had won, and the rewards given to C didn't need to be transferred to C through the third party. All of them were direct point-to-point transactions. This process was decentralization. The card players (miners) recorded their own achievements in the first game, and the third team won the first game, After the record is completed, a complete block is generated. But remember, this is only the first round. In the whole blockchain, this is just a node. The first eight rounds are finished, that is, eight nodes (blocks). Eight blocks are connected together to form a complete account book, which is the blockchain. Because everyone has one account book, it is a distributed account book. The purpose is to prevent someone from tampering with records. In the end, it is clear who wins or loses.
First of all, don't think too much about blockchain. It's a database storage system that is distributed all over the world and can work together. Different from the traditional database operation, where the read and write permissions are controlled by a company or a centralized hand (the centralized feature), blockchain believes that anyone who has the ability to set up a server node can participate in it. Gold diggers from all over the world deploy their own nodes locally and connect to the blockchain network to become a node in the distributed database storage system; Once joined, the node enjoys the same rights and obligations as all other nodes (decentralized, distributed features). At the same time, for those who carry out services on the blockchain, they can read and write to any node in the system. Finally, all nodes in the world will synchronize one after another according to some mechanism, so that the data of all nodes in the blockchain network is completely consistent
blockchain itself is a technology, so it can't be a fraud. Just like the normalized "P2P" finance in recent years, how many fraudsters are wearing the concept of P2P to illegally absorb public funds and cheat people's hard-earned money? But is "P2P" guilty? It's just an indivial to indivial mode of Internet finance. It not only creates profits, but also helps thousands of people get rid of poverty, so as to achieve a win-win situation between the poor and the poor. The problems of currency exchange digital currency trading platform
can not hinder the development of blockchain, such as simple payment verification, side chain, lightning network protocol and other technologies proposed and in-depth research, which has been the problem solved by blockchain
