Resource directory blockchain
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 information of bitcoin network transactions, Used to verify the validity of its information (anti-counterfeiting) and generate the next block
extended data
most blockchain public chains are limited by scalability. The biggest feature of blockchain technology is decentralization, which requires that all accounts in the network need to deal with the accounting process. Distributed accounting has high security, low misoperation rate, political neutrality and correctness
however, blockchain technology embraces these features at the same time, sacrificing scalability, unable to meet the personalized supervision, and slightly insufficient in protecting data privacy. Moreover, with the increase of the number of ledger, the interaction delay will increase exponentially, that is to say, the more ledger in the blockchain network, the higher the delay
zilliqa project's token name is ZIL, which has been circulated and traded on 23 exchanges. Mainstream exchanges such as fire coin and coin an support it, so it is very convenient to participate. ZIL's maximum supply is 21 billion, of which 12.6 billion will be released directly through contracts, and the other 8.4 billion will be released in the form of mining awards within 10 years
the main network of zilliqa will be launched at the end of 2018 or the beginning of 2019, and the mining reward is rich, especially in the early stage. The electric power cost of zilliqa mining is only 1 / 9 of that of Ethereum, so it is more feasible with less energy consumption. In addition, mining can be carried out through GPU graphics card miner, and can simultaneously double dig ZIL and eth, bringing higher benefits for miners
pay attention to "zilliqacn" to learn more about the progress of the project.
From the current mainstream blockchain projects, blockchain projects are mainly divided into four categories: the first category: currency; The second is platform; The third category: application category; The fourth type: asset token
currencies mainly act as the "exchange media" in the field of blockchain assets, and the exchange media refer to general equivalents, such as gold and silver bills in the past< (currency exchange on trading blockchain assets)
platform projects refer to the establishment of technical platforms to meet the needs of various blockchain application development, which can rece the threshold of application development on blockchain
application projects cover a wide range of fields, including finance, social networking, games, property rights protection, etc., and are also the fastest growing fields of blockchain assets
asset token project refers to the blockchain mapping of physical assets, that is, the physical assets on the chain. At present, there are no more than 10 varieties
01 currency
the first category is currency project, which is also the earliest blockchain project. Currency projects mainly include bitcoin and lightcoin. In addition, there is another kind of asset with the characteristics of anonymity. Its main functions include protecting the privacy of both sides of payment while realizing payment. The well-known ones are dash, monero and zcash. Currency is mainly used as the "exchange medium" in the field of blockchain assets. The exchange medium is the general equivalent you use to exchange goods. For example, gold, silver and silver bills can be used as the exchange medium in the past. At present, there are more than 2100 types of digital assets in the world, and the number of currency blockchain projects has increased rapidly recently. As of June 2018, bitcoin is still the largest market value
02 platform type
the second type is platform type blockchain project. The main function of platform type blockchain project is to establish a technical platform to meet the technical requirements of various blockchain application development; In short, platform applications allow developers to directly issue digital assets and write smart contracts on the blockchain. Smart contract is a computer program running on the blockchain database, which can be automatically executed under the conditions of its source code setting
for example, you develop a smart contract based on the house rent protocol on the blockchain. When the owner receives the rent, it will trigger the automatic execution and give the security key of the apartment to the tenant
the main function of platform blockchain projects is to establish the underlying technology platform, so that developers can do application development on the underlying technology platform. A considerable number of platforms are still in the development state. As of June 2018, Ethereum has the largest market value
03 application
the third category is application blockchain projects. Application projects are blockchain projects based on blockchain development platform (such as Ethereum), which can solve many problems in various fields of the real economy
for example, augur, Golem, vechain, omisego, which provides asset exchange and transfer services. Using blockchain technology, these projects can better solve the problems of trust and cross-border circulation. At the same time, using smart contracts and tokens on the blockchain, they can better realize automatic execution and greatly improve the efficiency of social and economic activities. Application blockchain projects cover a wide range of fields, including finance, social networking, games, property rights protection and so on. It is also the field with the fastest market value increment of blockchain projects at present
04 asset token
the fourth category is the asset token blockchain project. Asset token refers to linking the blockchain assets to physical assets such as gold and US dollars, which is the blockchain mapping of physical assets. As of February 2018, there are no more than 10 varieties. The typical representatives are usdt against US dollars, digix Dao against gold, Digix each token represents 1 gram of Gold Certified by the London Bullion Market Association. Asset token has the advantages of convenient transaction and safekeeping. First of all, asset token is more convenient for transaction. Because blockchain assets can be split, it has better liquidity
for example, at present, real estate needs to be transferred as a whole. If the real estate can be token, it can be split and purchased, which is more convenient for transaction. Secondly, the token of physical assets is more concive to custody. Gold is easy to wear out and cause losses in physical transactions, but there is no need for physical transfer after the token of physical assets, which is more concive to the custody of physical assets
Blockchain technology is widely used. Under the integration of new technologies, the main application scenarios of blockchain include finance and insurance, intelligent manufacturing, intelligent environmental protection, energy and power, health care, ecation, culture and innovation, smart city, social welfare, agriculture and many other fields
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blockchain + finance
blockchain can help financial institutions solve problems such as trust and data sharing
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blockchain + right art
Tianhe Guoyun's blockchain right system
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3. Blockchain + government
in statistics, voting, budget management and other aspects, blockchain can rece costs, improve efficiency, and increase transparency, so as to prevent the risk of failure of centralized system
4. Blockchain + insurance
fraud identification and risk prevention: by placing insurance claims under an unchangeable general ledger, blockchain helps to eliminate the common sources of fraud in the insurance instry
property insurance and accidental injury insurance: policies and shared ledgers recorded in the form of smart contracts can improve the efficiency of property insurance and accidental injury insurance
Health Insurance: blockchain technology enables medical records to be encrypted and shared among health service providers, thus improving the interoperability of the health insurance ecosystem
Reinsurance: the information security of reinsurance contracts on the blockchain platform can be ensured through the form of smart contracts, which can rece the amount of information and simplify the payment process between insurers and reinsurers
A: the main application fields of blockchain technology are finance, Internet of things and logistics, public service, digital right, insurance and public welfare
First, in the field of finance,
blockchain has great potential application value in international exchange, letter of credit, equity registration, stock exchange and other financial fields
Second, the Internet of things and logisticsblockchain can also be naturally combined in the field of Internet of things and logistics. Through blockchain, we can rece logistics costs, trace the proction and delivery process of goods, and improve the efficiency of supply chain management
Third, in the field of public service, blockchain is closely related to people's proction and life in the fields of public management, energy and transportation. However, the centralization of these fields also brings some problems, which can be transformed by blockchain Fourthly, in the field of digital right, through blockchain technology, works can be authenticated to prove the existence of text, video, audio and other works and ensure the authenticity and uniqueness of ownership In the field of insurance, insurance institutions are responsible for fund collection, investment and claim settlement, and often have higher management and operation costs Sixth, the data stored on the public welfare fieldblockchain is highly reliable and tamperable, which is naturally suitable for social public welfare scenarios. The relevant information in the public welfare process, such as donation project, collection details, fund flow, recipient feedback, etc., can be stored on the blockchain, and can be made transparent and public, which is convenient for social supervision
1. POW workload proof, which is familiar with mining, calculates a random number that meets the rules through and or operation, that is, obtains the bookkeeping right, sends out the data that needs to be recorded in this round, and stores it together with other nodes in the whole network after verification
advantages: complete decentralization, free access of nodes
disadvantages: bitcoin has attracted most of the computing power in the world, and other blockchain applications using POW consensus mechanism are difficult to obtain the same computing power to ensure their own security; Mining causes a lot of waste of resources; The period of reaching consensus is long, which is not suitable for commercial application.
2. Proof of rights and interests of POS, a mechanism of upgrading consensus of pow; According to the token proportion and time of each node; It can rece the difficulty of mining in equal proportion, so as to speed up the speed of finding random numbers< Advantages: to a certain extent, it shortens the time to reach a consensus
disadvantages: mining is still needed, which does not solve the pain point of commercial application in essence
3. Dpos share authorization certification mechanism is similar to the voting of the board of directors, in which the coin holders cast a certain number of nodes to verify and account on their behalf
advantages: greatly rece the number of participating verification and accounting nodes, which can achieve second level consensus verification
disadvantages: the whole consensus mechanism still depends on token, and many commercial applications do not need token to exist
4. Pool verification pool, which is based on traditional distributed consistency technology and data verification mechanism; It is a consensus mechanism widely used in the instry chain at present.
advantages: it can work without token, and realizes second level consensus verification on the basis of mature distributed consistency algorithms (pasox and raft)
disadvantages: the degree of decentralization is not as good as that of bictin; The multi center business model is more suitable for multi-party participation
it has great advantages in using consensus mechanism to ensure data consistency (the consensus mechanism is first proposed by ripple, and the network transaction synchronization mechanism with data correctness priority. In the consensus network, no matter how the software code changes, if you can't reach a consensus, you can't enter the network, let alone fork)
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PS: a little black, although the consensus mechanism can absolutely ensure that there will be no hard bifurcation at any time. However, the disadvantage of this mechanism is obvious, that is, it is much longer than the current bitcoin network to reach a consensus with other nodes. In extreme cases, the consequences of disconnection in ripple consensus mechanism network are also very terrible
it is possible that one day after the power failure in your home, the whole system will no longer be able to reach a consensus with other rippled nodes (in fact, the consensus mechanism requires more than 80% of the nodes to acknowledge your data before your submission will be accepted by other nodes, otherwise it will be rejected by exclusive nodes), Even you can only empty all your 500 GB data and resynchronize to connect to other ripple nodes
so at present, the existing rippled end is not suitable for civil use (if it is commercial, the impact is relatively small. For example, RL's own rippled node is hosted in Amazon cloud data center. If it has no response for a long time, it can make high claims, and there is almost no break in that place except for large disasters). This is one of the aspects RL has always wanted to improve.
(1) distributed ledger, that is, transaction bookkeeping is completed by multiple nodes distributed in different places, and each node records complete accounts, so they can participate in monitoring the legitimacy of transactions, At the same time, they can testify together
different from traditional distributed storage, the uniqueness of distributed storage of blockchain is mainly reflected in two aspects: one is that each node of blockchain stores complete data according to block chain structure, while traditional distributed storage generally stores data in multiple copies according to certain rules. Second, the storage of each node in the blockchain is independent and has the same status, which relies on the consensus mechanism to ensure the consistency of storage, while the traditional distributed storage generally synchronizes data from the central node to other backup nodes[ 8]
no single node can record the account data separately, so as to avoid the possibility that a single bookkeeper is controlled or bribed to record false accounts. In theory, unless all the nodes are destroyed, the accounts will not be lost, so as to ensure the security of the account data
(2) asymmetric encryption and authorization technology, the transaction information stored on the blockchain is public, but the account identity information is highly encrypted, which can only be accessed under the authorization of the data owner, thus ensuring the data security and personal privacy
(3) consensus mechanism is how to reach a consensus among all accounting nodes to determine the validity of a record, which is not only a means of identification, but also a means of preventing tampering. Blockchain proposes four different consensus mechanisms, which are suitable for different application scenarios and achieve a balance between efficiency and security
the consensus mechanism of blockchain has the characteristics of "the minority is subordinate to the majority" and "everyone is equal", in which "the minority is subordinate to the majority" does not completely refer to the number of nodes, but also can be the computing power, the number of shares or other characteristics that can be compared by computers“ "Everyone is equal" means that when the nodes meet the conditions, all nodes have the right to put forward the consensus results first, and then directly recognized by other nodes, and finally may become the final consensus results. Taking bitcoin as an example, the workload proof is adopted. Only when more than 51% of the accounting nodes in the whole network are controlled can a nonexistent record be forged. When there are enough nodes in the blockchain, this is basically impossible, thus eliminating the possibility of fraud.
(4) smart contract, which is based on these trusted and tamperable data, can automatically execute some pre-defined rules and terms. Take insurance as an example. If everyone's information (including medical information and risk occurrence information) is true and reliable, it is easy to carry out automatic claim settlement in some standardized insurance procts
of course, you can withdraw cash from local banks when you receive acceptance in other places you can ask the bank customer service according to the customer service of the bank