Which computers participate in the blockchain
blockchain includes public blockchain, joint (instry) blockchain and private blockchain. Public chain point-to-point e-cash system: bitcoin, smart contract and decentralized application platform: Ethereum
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. In essence, it is 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 a batch of bitcoin network transaction information, Used to verify the validity of its information (anti-counterfeiting) and generate the next block
extended data
according to the different degree of blockchain network centralization, three kinds of blockchains under different application scenarios are differentiated:
1. The blockchain with the whole network open and without user authorization mechanism is called public chain
2. The authorized nodes are allowed to join the network, and the information can be viewed according to the authority. It is often used in the inter agency blockchain, which is called alliance chain or instry chain
3. All the nodes in the network are in the hands of one organization, which is called private chain
alliance chain and private chain are also called licensing chain, and public chain is called non licensing chain
blockchain features
1, decentralization. Blockchain technology does not rely on additional third-party management institutions or hardware facilities, and there is no central control. In addition to the self-contained blockchain itself, each node realizes information self verification, transmission and management through distributed accounting and storage. Decentralization is the most prominent and essential feature of blockchain
2. Openness. Blockchain technology is based on open source. In addition to the private information of all parties involved in the transaction is encrypted, the data of blockchain is open to everyone. Anyone can query blockchain data and develop related applications through the open interface, so the information of the whole system is highly transparent
3. Independence. Based on consensus specifications and Protocols (similar to various mathematical algorithms such as hash algorithm used by bitcoin), the whole blockchain system does not rely on other third parties, and all nodes can automatically and safely verify and exchange data in the system without any human intervention
4. Safety. As long as 51% of all data nodes cannot be controlled, the network data cannot be arbitrarily manipulated and modified, which makes the blockchain itself relatively safe and avoids subjective and artificial data changes
5. Anonymity. Unless there are legal requirements, technically speaking, the identity information of each block node does not need to be disclosed or verified, and the information can be transferred anonymously
in the early stage of the development of the blockchain instry, many enterprises and institutions formed a blockchain alliance to share the research results of blockchain technology and seek wider application of blockchain technology
in the past two years, blockchain alliances have emerged. As of July 2017, there are R3 composed of more than 40 international banks, hyperledger initiated by Linux foundation, Zhongguancun blockchain Instry Alliance located in the core hinterland of China's Internet, China ledger alliance jointly initiated by 11 institutions, gold chain alliance jointly established by 25 financial institutions, and so on Russia's blockchain alliance, known as "Russian version R3", seeks to combine with micro finance, Qianhai international blockchain ecosphere alliance led by Shenzhen Qianhai administration, and Lujiazui blockchain Financial Development Alliance in Lujiazui
many organizations and talents join to promote the vigorous development of blockchain.
Blockchain instry has great growth potential, and five aspects promote the healthy development of Technology Virtual reality and other technologies are another emerging technology that will have a significant impact on the future, which is expected to promote human beings from the era of information internet to the era of value Internet
some countries and regions in the United States, Japan and the European Union have promoted the development of blockchain as an important national development strategy, and vigorously promoted the development and application of blockchain technology. China also attaches great importance to the technological innovation and instrial development of blockchain. With the joint participation of it and other enterprises, a large number of new enterprises, new procts, new models and new applications have emerged. The application of blockchain in the fields of finance, government affairs, energy, medical and other instries has graally expanded, and is becoming an important force to drive the technological proct innovation and instrial transformation of various instries
the development of blockchain can be divided into three stages, namely, blockchain 1.0, represented by bitcoin and related financial infrastructure applications, and blockchain 2.0, represented by smart contract. At present, it is graally moving towards blockchain 3.0, which is based on blockchain technology and more complex in-depth application of smart contract
statistical analysis of blockchain investment and financing in the first half of the year. According to the statistical data of in depth analysis report on business model innovation and investment opportunities of China's blockchain instry published by foresight Instry Research Institute, in the first half of 2018, the amount of financing in the blockchain field was about 10.7 billion, with a year-on-year growth rate of 1426% compared with the same period in 2017; The number of investment and financing events in the field of blockchain has reached 205, and it is expected that the investment in the field of blockchain will usher in another peak this year
according to the distribution of investment and financing rounds in China's blockchain field, the proportion of investment rounds in the start-up period (before round b) is more than 95%, with the joint investment of many instry pioneers, and most enterprises are still running around
statistics and growth of blockchain investment and financing in the first half of 2014-2018
data source: China attaches great importance to the development and application of blockchain technology. Driven by multiple forces such as policy, technology and market, the pace of blockchain innovation has been accelerating. It has been deeply integrated with cloud computing, big data, Internet of things and other technologies. The scope of exploration and application has also expanded from digital assets to supply chain management, intelligent manufacturing, instrial Internet, social welfare, right protection and other fields
five aspects to promote the healthy development of blockchain technology, promote the high-quality development of digital economy
1, in-depth study and grasp the development trend of blockchain technology and instry. Pay close attention to the international development frontier, jointly promote the research of blockchain related technology and instry, promote the standardization of blockchain development instry behavior, and create a good development environment
2. Strengthen the construction of core technology capacity of blockchain
establish and improve the collaborative promotion mechanism among backbone enterprises, universities and research institutions, guide it enterprises to strengthen technical reserves, accelerate the breakthrough of key core technologies, and improve the performance, efficiency and security of blockchain
3. Support entrepreneurship and innovation in the field of blockchain
encourage cross-border integration between blockchain enterprises and user units, guide instry organizations to establish public service platforms, support third-party organizations to carry out evaluation and detection of blockchain services, promote rich instrial applications of blockchain, and serve the transformation and upgrading of the real economy
4. Actively build and improve the blockchain standard system
accelerate the development and application of key standards, and graally build a perfect standard system. Actively connect with ITU, ISO and other international standards organizations, substantially participate in more international standardization work, and actively contribute more "Chinese power"
5. Accelerate the improvement of the policy environment for blockchain development
support qualified enterprises to carry out application innovation and mode innovation, and guide and encourage enterprises, universities and scientific research institutes to jointly cultivate professional talents needed for blockchain development. Support eligible blockchain enterprises to enjoy the preferential tax policies of the state to support the development of software instry and small and medium-sized enterprises
the instrial scale is small, but the growth potential is huge
the blockchain economy is on the eve of the outbreak period. The financial instry is relatively widely used, and the application of other instries has also entered the stage of exploration and development. It is estimated that from 2017 to 2022, the direct market value of blockchain will increase from US $410 million to US $7.68 billion, with a compound annual growth rate of 79.6%. It is estimated that all kinds of extended business based on blockchain will reach US $100 billion in 2020
instry application areas continue to expand
the financial instry takes the lead in the application of blockchain technology, and many financial applications have been implemented; Medical instry is an important area of blockchain application, which can better protect privacy, improve service quality and management efficiency; The demand of social authentication for blockchain is rising rapidly to solve the proof problem caused by information asymmetry; The application of blockchain technology in communication, supply chain and other fields is expanding rapidly
blockchain (English: blockchain or block chain) is a kind of distributed database . You may have heard about bitcoin, which is the core technology. Blockchain is a series of data blocks generated by cryptography. Each data block contains the information of a network transaction, which is used to verify the validity of the information and generate the next block. In a popular concept, blockchain is an account that everyone can keep. In a company or organization, most people only have the right to keep accounts, while only a few people with professional training have the right to keep accounts. Of course, blockchain is not an account book in the traditional sense. It has the following three key points in technical principle: first, decentralization. In a network practicing blockchain technology, each computer covered by it can read and add records. From the perspective of account book, they are the people who keep accounts together, and there is no authoritative person to guide and correct them. Second, asymmetric encryption. Although everyone can remember this account, they will not be able to read it unless they are in the Bureau. Because, in the accounting process, everyone follows the unified encryption rules, but when reading, they must use their own unique decryption method. Therefore, although everyone keeps this constantly updated account, the part they can read is only the one they can decrypt, that is, the part related to themselves. Third, time stamp. That is, time stamp (English: timestamp), refers to the string or coded information used to identify the recorded time and date. Each block on the blockchain is arranged in sequence according to the time it is generated, and is confirmed by collective authentication. Moreover, previous records cannot be modified. Just like in an account, we can index and verify the previous content through the records after a point in time. Once these contents are confirmed, it will be more difficult to tamper with them
blockchain technology is to maintain a growing distributed database of data records. These data are associated with all the data written before through cryptography technology, which makes it difficult for the third party or even the owner of the node to tamper with. Block contains the data that need to be saved in the database, and these data are written into the database through block organization. Chain usually refers to the use of Merkle tree and other methods to check whether all the current blocks have been modified. This is familiar to code farmers who have used git for a long time. Recall how to modify git's history
blockchain technology is mainly divided into three categories, which are open, collaborative and private
public blockchain
example: bitcoin, Ethereum frontier. The data on the public blockchain can be accessed by all people, and all people can issue transactions waiting to be written into the blockchain. Participants in the consensus process (corresponding to the miners in bitcoin) maintain the security of the database through cryptography technology and built-in economic incentives. Open blockchain is completely distributed
highlights and pain points: the open blockchain is completely distributed and has all the characteristics of bitcoin. However, it needs sufficient cost to maintain the system operation and relies on built-in incentives. At present, only bitcoin in the public blockchain is safe enough. If the algorithm is the same as bitcoin, it will be safe; There are no built-in rewards, but they are not; It's easy to concentrate on the attack of computing power (for example, as long as the raid sweeps goods and a large number of graphics cards), and take jujube pills. The more valuable the data on the open blockchain is, the more important it is to examine its security, transaction cost and system scalability
federated blockchain
example: audit system tried by hyperledger and Deloitte. The nodes participating in the blockchain are selected in advance, and there is likely to be a good network connection between the nodes. Other consensus algorithms without workload proof can be used on such a blockchain. For example, a blockchain has been established among 100 financial institutions, and more than 67 institutions must agree to reach a consensus. The data on such a blockchain can be public or internal to these node participants. Distributed in a partial sense
highlights and pain points: collaborative blockchain can achieve a good connection between nodes, only need a little cost to maintain operation, provide rapid transaction processing and low transaction costs, has good scalability (but the scalability will decline with the increase of nodes), and data can have certain privacy. Developers have the ability to change the protocol under the consensus. There is no problem with bitcoin hard fork, but it also means that everyone can tamper with the data together under the consensus. Collaborative blockchain also means that the application scope of this blockchain will not be too wide, lacking the network propagation effect of bitcoin
private blockchain
example: Eris instries. The participating nodes are only users themselves, and the access and use of data have strict authority management. Most of the blockchain technologies recently announced by some financial institutions for internal use are vague, but they are probably all within this scope
highlights and pain points: private blockchain is actually a confusing term. Such a system is nothing more than a shared database in the traditional sense. Merkle tree and other methods are used to try to show that the data in it is verifiable. There are already mature solutions for such databases, and Merkle tree is only one of many mature solutions. It's easy for these projects to be "like eggs". Because the user has the final say, the data inside can not be changed, and there is not much protection for the third party. Therefore, many private blockchains exist by attaching to bitcoin, such as recording system snapshots to bitcoin regularly