Make blockchain connected
according to Xiao Wang, the concept of blockchain as a service (baas) is mainly proposed by Microsoft and IBM. To put it bluntly, it is actually a new type of cloud service, a cloud service combined with blockchain technology. For example, Microsoft's azure cloud computing platform and IBM's bluemix garage cloud platform all provide blockchain as a service baas
blockchain as a service (baas) is a space created by enterprises such as Microsoft and IBM from their own cloud service network to run a blockchain node. Compared with ordinary nodes and exchange nodes, the main purpose of baas nodes is to quickly establish the development environment they need, and provide a series of operation services based on blockchain, such as search query, transaction submission, data analysis, etc. these services can be centralized or decentralized to help developers verify their concepts and models faster. The service of baas node is reflected in: it is more instrumental and easy to create, deploy, run and monitor 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 new application mode of distributed data storage, point-to-point transmission, consensus mechanism, encryption algorithm and other computer technologies
the so-called consensus mechanism is a mathematical algorithm to establish trust and obtain interests between different nodes in the blockchain system
in a narrow sense, blockchain is a kind of chain data structure that combines data blocks in chronological order in a sequential way, and it can not be tampered with and forged by cryptography
broadly speaking, blockchain technology is a new distributed infrastructure and computing method, which uses blockchain data structure to verify and store data, uses distributed node consensus algorithm to generate and update data, uses cryptography to ensure the security of data transmission and access, and uses intelligent contract composed of automated script code to program and operate data< Advantages:
1) the algorithm is simple and easy to implement
2) there is no need to exchange additional information between nodes to reach a consensus
3) it takes a lot of cost to destroy the system< Disadvantages:
1) waste of energy
2) it is difficult to shorten the block confirmation time
3) the new blockchain must find a different hash algorithm, otherwise it will face bitcoin attack
4) it is easy to generate bifurcation and needs to wait for multiple confirmations
5) there is no finality, and checkpoint mechanism is needed to make up for it.
According to experts, blockchain can be understood as a distributed public ledger, which is connected by various blocks into a chain. In the traditional bookkeeping system, the bookkeeping right is controlled by the central server
on the "account book" of blockchain, every point in the chain can record information on it, forming a point-to-point accounting system. Therefore, blockchain technology is considered as a decentralized technology
For example, in a village of 100 people, Zhang San bought a cow from Li Si and paid him 10000 yuan. In the past, he had to rely on Zhao Liu, a middleman, to transfer his 10000 yuan to Li Siwith the blockchain system, Zhang San can directly record his 10000 yuan to Li Si's account book, and the transaction information will be transmitted to the whole village, that is, the whole blockchain system, so that other 98 people can see the information. The whole transaction process is recorded by the system, which has the advantage of traceability to prevent the loss of Zhao Liu's account book or Li Si's denial of account
extended data
in 2008, Nakamoto first proposed the concept of blockchain. In the following years, blockchain became the core component of electronic currency bitcoin: as a public account book for all transactions. By using peer-to-peer network and distributed timestamp server, the blockchain database can be managed independently
the blockchain invented for bitcoin makes it the first digital currency to solve the problem of repeated consumption. The design of bitcoin has become a source of inspiration for other applications
blockchain is composed of a series of blocks generated by cryptographic algorithm. Each block is filled with transaction records, and the blocks are connected in sequence to form a chain structure, which is the blockchain ledger
taking bitcoin as an example, when miners generate new blocks, they need to calculate the new hash value and random number according to the hash value, new transaction block and random number of the previous block. In other words, each block is generated on the basis of the previous block data, which ensures the uniqueness of the blockchain data
because subtle changes in transaction records will completely change the result of hash value, miners can't cheat when competing for computing power. Each miner must wait until the previous block is generated before starting to calculate the qualified random number according to the data of the previous block, which ensures the fairness of mining.