Core technologies and application fields of blockchain
broadly speaking, blockchain technology is a new distributed infrastructure and computing paradigm, 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
as we all know, blockchain technology is an independent underlying architecture from bitcoin system. From the perspective of architecture model, it is a set of distributed ledger, which is naturally used for bookkeeping
in the blockchain technology, if you want to generate accounting records, you need to have the transaction and flow of funds. Therefore, in the initial blockchain technology, the cryptocurrency corresponding to the main network is used as circulation goods, and the circulation transaction records of cryptocurrency between the accounts of the main network of the blockchain will be recorded on the main network
different from other transaction record databases, transaction records on the main network of blockchain technology will be recorded on all block nodes (i.e. all data blocks) in the main network, which is the so-called decentralization principle. That is to say, in blockchain technology, there is no central database to store all records, Every block on the chain has the transaction data of the whole chain, that is to say, every data block is the center
another feature of blockchain technology is that it can't be tampered with, because every transaction on the blockchain will be recorded in all blocks on the chain, so no single data block can change the record. Even if you change it, all other data blocks will also record real data, and each group of data can be traced back to the first time
because of these characteristics of blockchain technology, after the advent of bitcoin, blockchain has also attracted a lot of attention, and many people also began to want to use blockchain technology to make a centerless, traceable and unchangeable data, so as to ensure the credibility of the data
however, blockchain technology also faces many problems, such as single application scenario, non modifiable original error data, non recoverable currency stolen by hackers, etc.
From the perspective of technology and architecture, I will tell you my understanding of blockchain in common language
what is blockchain? In a word, blockchain is a storage system. To be more specific, blockchain is a distributed storage system without an administrator and each node has all the data
What are the common storage systems like
first, how to ensure high availability
the common storage system usually uses "rendancy" to solve the problem of high availability. As shown in the figure above, if the data can be copied into several copies and rendant to multiple places, high availability can be guaranteed. The data in one place is hung, and there is data in other places. For example, the master-slave cluster of MySQL is the same principle, and the raid of disk is also the same principle
two points need to be emphasized in this place are: data rendancy often leads to consistency problems
1. For example, in the master-slave cluster of MySQL, there is actually a delay in reading and writing, which means there is a inconsistency in reading and writing in a short period of time. This is a side effect of data rendancy
The second point is that data rendancy often reces the efficiency of writing, because data synchronization also consumes resources. If you add two slave libraries, the write efficiency will be affected. The common storage system is to use rendancy to ensure the high availability of dataso the second question, ordinary storage system, can write more
the answer is yes, for example, take this graph as an example:
in fact, MySQL can do a master-slave synchronization of al masters, master-slave synchronization of al masters, two nodes can be written at the same time. If you want to do a multi room multi live data center, in fact, multi room multi live data synchronization. What we should emphasize here is that multi-point writing often leads to the consistency problem of writing conflicts. Take MySQL as an example, suppose that the attribute of a table is self incrementing ID, then the data in the database is 1234 now. If one of the nodes writes and inserts a piece of data, it may become 5, and then these 5 pieces of data are synchronized to another master node, Before synchronization, if another write node inserts a piece of data, a piece of data with self incrementing ID of 5 will be generated. Then, after the generation, synchronize to another node, and the synchronized data will conflict with the two local 5's after it arrives, which will lead to synchronization failure and write consistency conflict. This problem will occur in the case of multi-point writing
how to ensure consistency in multi-point writing
the reform "Swan class" gives you more technical work
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
1. Blockchain links
as the name suggests, blockchain is a chain composed of blocks. Each block is divided into block head and block body (including transaction data). The block head includes the prevhash value (also known as hash value) of the previous block used to realize the block link and the random number (nonce) used to calculate the mining difficulty. The hash value of the previous block is actually the hash value of the head of the previous block, and the random number calculation rule determines which miner can obtain the right to record the block
2. Consensus mechanism
blockchain is accompanied by the birth of bitcoin, which is the basic technology architecture of bitcoin. Blockchain can be understood as an Internet-based decentralized accounting system. A decentralized digital currency system like bitcoin requires the consistency of accounting of honest nodes without a central node, which needs blockchain to complete. Therefore, the core of blockchain technology is a consensus mechanism to reach a consensus on the legitimacy of transactions between indivials without mutual trust without central control
there are four main types of consensus mechanisms in blockchain: pow, POS, dpos and distributed consistency algorithm
3. Unlocking script
script is an important technology to realize automatic verification and contract execution on blockchain. Every output of every transaction does not point to an address in the strict sense, but to a script. A script is like a set of rules that constrain how the receiver can spend the asset locked on the output
the validation of transactions also depends on scripts. At present, it depends on two kinds of scripts: Lock script and unlock script. Locking script is a condition added to the output transaction, which is realized by a script language and located in the output of the transaction. The unlocking script corresponds to the locking script. Only when the conditions required by the locking script are met can the assets corresponding to the script be spent, which is located in the input of the transaction. Many flexible conditions can be expressed by script language. Interpretation script is similar to the "virtual machine" in our programming field, which runs in every node of the blockchain network in a distributed way
4. Transaction rules
blockchain transaction is not only the basic unit of a block, but also the actual effective content recorded by the blockchain. A blockchain transaction can be a transfer, or the deployment of smart contracts and other transactions
as far as bitcoin is concerned, a transaction refers to a single payment transfer. The transaction rules are as follows:
1) the input and output of the transaction cannot be empty
2) for each input of a transaction, if its corresponding utxo output can be found in the current transaction pool, the transaction will be rejected. Because the current transaction pool is the transaction not recorded in the blockchain, and each input of the transaction should come from the confirmed utxo. If it is found in the current trading pool, it is Shuanghua trading
3) for each input in a transaction, the corresponding output must be utxo
4) each input unlocking script must verify the compliance of the transaction together with the corresponding output locking script
5. Transaction priority
the priority of blockchain transaction is determined by the blockchain protocol rules. For bitcoin, the priority of a transaction to be included in a block is determined by the time when the transaction is broadcast to the network and the amount of the transaction. With the increase of transaction broadcast time on the network and the increase of transaction chain age, the priority of transaction will be improved and eventually be included by the block. For Ethereum, the priority of the transaction is also related to the transaction fee that the publisher is willing to pay. The higher the transaction fee that the publisher is willing to pay, the higher the priority that the transaction is included in the block
6. Merkle proof
the original application of Merkle proof is bitcoin, which was described and created by Satoshi Nakamoto in 2009. Bitcoin blockchain uses Merkle proof to store transactions in each block. So that the transaction can not be tampered with, but also easy to verify whether the transaction is included in a specific block
7. RLP
RLP (recursive length prefix) is one of the main encoding methods of object serialization in Ethereum. Its purpose is to encode the sequence of arbitrary nested binary data.
the traceability of the blockchain enables the records of every step of data collection, transaction, circulation, and calculation and analysis to be kept on the blockchain, which makes the quality of data obtain unprecedented strong trust endorsement, and also ensures the correctness of data analysis results and the effect of data mining
it can be said that blockchain is another epoch-making breakthrough in the Internet instry in terms of cloud computing and big data technology.