Distributed theory does not represent decentralization
Publish: 2021-04-14 15:36:32
1. blockchain is not broken. Blockchain itself is a kind of decentralized database, which can be accessed but not tampered with. Therefore, it is a very secure data chain
2. One of the characteristics of media theory is the wide ambiguity of various views. On the relationship between media and society, one of the focuses of the debate is the theoretical debate between "media centric" and "social centric", First, the view of "media center" lays particular stress on the field of media activities. It holds that the mass media, influenced by the irresistible driving force of the development of communication technology, has formed an independent force beyond the law of social movement. Mass communication has its own mode of operation and logic, highlighting the autonomy and influence of the media“ The view of "social center" regards the mass media as the reflection of political and economic forces, and holds that the media, just like its original intention, is only the carrier of information transmission. Therefore, the media theory is only a special application of the larger social theory. Second, the "media center" theory holds that the mass media has the ability to "acculturate" and "cultivate" the society, And regard the mass media as the main instigator of social change“ The theory of "social center" holds that media is always under the influence of social forces. It belongs to society and bears special responsibility for society. It is not difficult to see that the differences between theories are irreconcilable e to different footholds
3. Compared with the traditional centralized storage and centralized cloud services, the two complement each other and expand the market of data storage and computing, which will constitute the two cornerstones of the future digital economy. China has efficient, stable and cheap power and network infrastructure, which provides sufficient soil for the development of decentralized cloud computing. Taking IPFs as an example, 90% of the total network computing power of IPFs is located in China. In the future, China will become the leader of IPFs. Taking xnmatrix as an example, it has become a global computing power leading decentralized cloud computing platform.
4. The essence of blockchain is a distributed ledger. For example, the bank system is also the account book, which has a complete set of information system to store various transaction information such as access, loan, exchange and so on. Blockchain has several keywords:
1. Distributed: ledger is not only stored in one place, but in many places
2. General ledger: you can determine that you are not necessarily a machine stored general ledger through the network, but you can at least obtain the general ledger from the network
3. Decentralization: "distributed" is not a general distribution, but a decentralized distribution. No one can control and tamper with it, its accounting rules are based on some designed mathematical method to account for all rights. How to test, how to use, are in accordance with an open method to complete, so in essence is an account book
coin Ying China is the first to introce blockchain into the crowdfunding instry, making crowdfunding more open, transparent and simple.
1. Distributed: ledger is not only stored in one place, but in many places
2. General ledger: you can determine that you are not necessarily a machine stored general ledger through the network, but you can at least obtain the general ledger from the network
3. Decentralization: "distributed" is not a general distribution, but a decentralized distribution. No one can control and tamper with it, its accounting rules are based on some designed mathematical method to account for all rights. How to test, how to use, are in accordance with an open method to complete, so in essence is an account book
coin Ying China is the first to introce blockchain into the crowdfunding instry, making crowdfunding more open, transparent and simple.
5. It can be transferred by the will of the people around, not by the central opinion. Constantly make changes to achieve longer-term goals.
6. Data has been surging, and it's definitely an opportunity. IPFs and filecoin are so powerful, but another project, hurricane ecology, is also OK. It was built by the original storm video team. I think with the technical advantages of storm, the hurricane ecology will not be bad.
7. General exchanges open accounts free of charge
8. What do pow, POS and dpow mean
when it comes to blockchain, we must talk about its consensus mechanism. If we don't understand the consensus mechanism of blockchain, we can't understand the real meaning of blockchain. So, what about the consensus mechanism of today's blockchain
what is the consensus mechanism
what is consensus? Take its literal meaning, that is & quot; Common understanding & quot
people are different, not only in stature, appearance and ability, but also in culture, views, ideas, interests and so on
consensus, in short, is the consensus reached by members of a group in a certain aspect
we have learned that trust is a major pain point in the operation of society. Banks have their own credit system. In the past, the financial system only served a few entrepreneurs, because the establishment of credit system cost a lot. Later, Alipay had sesame credit. Credit has already been related to many aspects of life, credit card size, spending amount of flowers, sesame credit and high going abroad can be avoided. We are enjoying the convenience of credit
the essence of blockchain is decentralization, and the core of decentralization is consensus mechanism. The consensus mechanism on blockchain mainly solves the problems of who constructs the block and how to maintain the unity of blockchain
the goal of the blockchain consensus mechanism is to make all honest nodes save consistent blockchain views, while meeting two properties:
1) consistency: the prefix part of the blockchain saved by all honest nodes is exactly the same
2) effectiveness: the information released by an honest node will be recorded in its own blockchain by all other honest nodes
the confidence of blockchain is mainly reflected in the fact that users distributed in the blockchain do not need to trust the other party of the transaction or a centralized organization, and only need to trust the software system under the blockchain protocol to realize the transaction
what is the consensus mechanism? What do pow, POS and dpow mean
the necessity of consensus mechanism
in a distributed system, multiple hosts form a network cluster through asynchronous communication. In such an asynchronous system, state replication between hosts is needed to ensure that each host can reach a consensus. Error messages may appear in asynchronous systems and propagate continuously, so it is necessary to define fault-tolerant protocols in default unreliable asynchronous networks to ensure that all hosts reach a safe and reliable state consensus, which is the necessity of consensus mechanism
the premise of such self-confidence is the consensus mechanism of the blockchain, that is, in a market of mutual distrust, the sufficient and necessary condition for each node to reach an agreement is that each node will spontaneously and honestly abide by the pre-set rules in the agreement to judge the authenticity of each record for the sake of maximizing its own interests, Finally, the records judged to be true are recorded in the blockchain. Attachments-2018-08-9yy7vrha5b738e3d96021. JPG
in other words, if each node has its own independent interests and competes with each other, it is almost impossible for these nodes to conspire to cheat you, especially when they have public reputation in the network. Blockchain technology is the use of a set of mathematical algorithms based on consensus to establish & quot; Trust & quot; Network, so as to create new credit through technical endorsement rather than centralized credit institutions
Introction to several consensus mechanisms in today's blockchain
there are many consensus mechanisms in blockchain, but none of them is perfect, or suitable for all application scenarios
POW workload proof
each node in the whole system provides computing power (referred to as computing power) for the whole system. Through a competitive mechanism, the node with the best computing work can be rewarded by the system, that is, to complete the allocation of newly generated currency. It is simply understood that more work pays more. Currency blockchains such as bitcoin and LTC apply POW mechanism
advantages
completely decentralize the nodes to get in and out freely, the algorithm is simple, easy to realize, and the cost of destroying the system is huge. As long as the computing power of the network destroyer does not exceed 50% of the total computing power of the network, the transaction status of the network can reach an agreement
disadvantages
waste energy, which is the biggest disadvantage. It is difficult to shorten the block confirmation time, for example, bitcoin can only do 7 transactions per second, It is not suitable for commercial application. A new blockchain must find a different hash algorithm, or it will face bitcoin's computing power attack. It has high requirements on the performance of the nodes, and the network environment is prone to bifurcation. It needs to wait for multiple confirmations, and can not reach the final agreement
POS proof of equity
also known as proof of equity, which is similar to you deposit your property in the bank, This model will allocate interest to you according to the amount and time of cryptocurrency you hold< Advantages
low requirements for node performance and short consensus time
disadvantages
there is no final consistency, so checkpoint mechanism is needed to make up for the finality
dpow is an evolutionary scheme of pos. in conventional POW and POS, any newly added block needs to be confirmed by all nodes of the whole network, which greatly affects the efficiency
dpos is similar to the voting mechanism of modern board of directors, which elects representatives to vote and make decisions. The N selected accounting nodes are used for the creation, verification, signature and mutual supervision of new blocks, which greatly reces the time and computational cost of block creation and confirmation
advantages
greatly rece the number of nodes participating in verification and accounting, which can achieve second level consensus verification
disadvantages
sacrifice the concept of decentralization, which is not suitable for public chain
pbft practical Byzantine fault tolerance
practical Byzantine fault tolerance mechanism is a kind of adoption & quot; Permission to vote, minority subject to majority & quot; The consensus mechanism allows Byzantine fault tolerance, allows strong supervision nodes to participate, has the ability of authority classification, higher performance and lower energy consumption, and each round of bookkeeping will be jointly elected by the whole network nodes, allowing 33% of nodes to do evil, and the fault tolerance rate is 33%. Practical Byzantine fault tolerance is especially suitable for the application scenario of alliance chain<
advantages
will deviate from centralization, the existence of cryptocurrency and reward mechanism will proce Matthew effect, making the poor poorer and the rich richer in the community, achieving high consensus efficiency and realizing high-frequency trading
disadvantages
when only 33% of the nodes in the system are running, the system will stop running
dbft authorizes Byzantine fault tolerance
this mechanism is to use rights to select bookkeeper, Then bookkeepers reach a consensus through Byzantine fault-tolerant algorithm. The core of Byzantine fault tolerance mechanism is to ensure the system's finality to the maximum extent, so that the blockchain can be applied to real financial application scenarios
advantages
Professional bookkeeper can tolerate any type of error, bookkeeping is completed by multiple people, each block has finality, no bifurcation, the reliability of the algorithm has strict mathematical proof
disadvantages
when one-third or more bookkeepers stop working, the system will not be able to provide services, when one-third or more bookkeepers jointly commit crimes, The system may be bifurcated
pool verification pool
based on traditional distributed consistency technology and data verification mechanism
advantages
it can work without cryptocurrency. Based on the mature distributed consistency algorithms (pasox, raft), it realizes second level consensus verification
disadvantages
the degree of decentralization is not as good as bitcoin, which is more suitable for the multi center business model with multi participation
Paxos
this is a traditional distributed consensus algorithm, which is a consensus mechanism based on election leaders. The leader node has absolute authority, and allows strong supervision node to participate, which has high performance and low resource consumption. Generally, all nodes have wired access mechanism, but there is no malicious node in the election process, which is not fault-tolerant< In Paxos algorithm, nodes are divided into three types:
proposer: put forward a proposal and wait for everyone's approval. The client often plays the role
acceptor: responsible for voting on the proposal. Usually, the server plays this role
learner: is informed of the result of the case settlement, and unifies with it, and does not participate in the voting process. Maybe the client or server
Paxos can ensure that the system can reach a consensus when more than 50% of the normal nodes exist
REBO consensus mechanism
REBO consensus algorithm enables a group of nodes to form a consensus based on the special node list. The initial special node list is like a club. To accept a new member, it must be voted by 51% of the members of the club. Consensus follows the & quot; 51% rights;, Outsiders have no influence. Since the club starts with centralization, it will always be, and if it starts to corrupt, shareholders can do nothing. Like bitcoin and peercoin, the reborn system separates shareholders from their voting rights, so it is more centralized than other systems
peercoin
peercoin (PPC) is a combination of proof of pow workload and proof of POS equity. POW is mainly used to issue currency. In the future, with the increase of mining difficulty, the output will decrease, and the system security will be mainly maintained by POS
in the blockchain network, e to different application scenarios, different goals are designed, and different blockchain systems adopt different consensus algorithms. Each consensus algorithm is not perfect and has its own advantages and limitations
blockchain solves the problems of transmitting trusted information and value transfer on untrusted channels, while consensus mechanism solves the problem of how blockchain achieves consistency in distributed scenarios
although the blockchain is still in the early stage of development, and the instry development is still facing some obstacles, the society has recognized the value of the blockchain enough, the pace of blockchain development will never stop, and the instry development will certainly find a way to break through the obstacles.
when it comes to blockchain, we must talk about its consensus mechanism. If we don't understand the consensus mechanism of blockchain, we can't understand the real meaning of blockchain. So, what about the consensus mechanism of today's blockchain
what is the consensus mechanism
what is consensus? Take its literal meaning, that is & quot; Common understanding & quot
people are different, not only in stature, appearance and ability, but also in culture, views, ideas, interests and so on
consensus, in short, is the consensus reached by members of a group in a certain aspect
we have learned that trust is a major pain point in the operation of society. Banks have their own credit system. In the past, the financial system only served a few entrepreneurs, because the establishment of credit system cost a lot. Later, Alipay had sesame credit. Credit has already been related to many aspects of life, credit card size, spending amount of flowers, sesame credit and high going abroad can be avoided. We are enjoying the convenience of credit
the essence of blockchain is decentralization, and the core of decentralization is consensus mechanism. The consensus mechanism on blockchain mainly solves the problems of who constructs the block and how to maintain the unity of blockchain
the goal of the blockchain consensus mechanism is to make all honest nodes save consistent blockchain views, while meeting two properties:
1) consistency: the prefix part of the blockchain saved by all honest nodes is exactly the same
2) effectiveness: the information released by an honest node will be recorded in its own blockchain by all other honest nodes
the confidence of blockchain is mainly reflected in the fact that users distributed in the blockchain do not need to trust the other party of the transaction or a centralized organization, and only need to trust the software system under the blockchain protocol to realize the transaction
what is the consensus mechanism? What do pow, POS and dpow mean
the necessity of consensus mechanism
in a distributed system, multiple hosts form a network cluster through asynchronous communication. In such an asynchronous system, state replication between hosts is needed to ensure that each host can reach a consensus. Error messages may appear in asynchronous systems and propagate continuously, so it is necessary to define fault-tolerant protocols in default unreliable asynchronous networks to ensure that all hosts reach a safe and reliable state consensus, which is the necessity of consensus mechanism
the premise of such self-confidence is the consensus mechanism of the blockchain, that is, in a market of mutual distrust, the sufficient and necessary condition for each node to reach an agreement is that each node will spontaneously and honestly abide by the pre-set rules in the agreement to judge the authenticity of each record for the sake of maximizing its own interests, Finally, the records judged to be true are recorded in the blockchain. Attachments-2018-08-9yy7vrha5b738e3d96021. JPG
in other words, if each node has its own independent interests and competes with each other, it is almost impossible for these nodes to conspire to cheat you, especially when they have public reputation in the network. Blockchain technology is the use of a set of mathematical algorithms based on consensus to establish & quot; Trust & quot; Network, so as to create new credit through technical endorsement rather than centralized credit institutions
Introction to several consensus mechanisms in today's blockchain
there are many consensus mechanisms in blockchain, but none of them is perfect, or suitable for all application scenarios
POW workload proof
each node in the whole system provides computing power (referred to as computing power) for the whole system. Through a competitive mechanism, the node with the best computing work can be rewarded by the system, that is, to complete the allocation of newly generated currency. It is simply understood that more work pays more. Currency blockchains such as bitcoin and LTC apply POW mechanism
advantages
completely decentralize the nodes to get in and out freely, the algorithm is simple, easy to realize, and the cost of destroying the system is huge. As long as the computing power of the network destroyer does not exceed 50% of the total computing power of the network, the transaction status of the network can reach an agreement
disadvantages
waste energy, which is the biggest disadvantage. It is difficult to shorten the block confirmation time, for example, bitcoin can only do 7 transactions per second, It is not suitable for commercial application. A new blockchain must find a different hash algorithm, or it will face bitcoin's computing power attack. It has high requirements on the performance of the nodes, and the network environment is prone to bifurcation. It needs to wait for multiple confirmations, and can not reach the final agreement
POS proof of equity
also known as proof of equity, which is similar to you deposit your property in the bank, This model will allocate interest to you according to the amount and time of cryptocurrency you hold< Advantages
low requirements for node performance and short consensus time
disadvantages
there is no final consistency, so checkpoint mechanism is needed to make up for the finality
dpow is an evolutionary scheme of pos. in conventional POW and POS, any newly added block needs to be confirmed by all nodes of the whole network, which greatly affects the efficiency
dpos is similar to the voting mechanism of modern board of directors, which elects representatives to vote and make decisions. The N selected accounting nodes are used for the creation, verification, signature and mutual supervision of new blocks, which greatly reces the time and computational cost of block creation and confirmation
advantages
greatly rece the number of nodes participating in verification and accounting, which can achieve second level consensus verification
disadvantages
sacrifice the concept of decentralization, which is not suitable for public chain
pbft practical Byzantine fault tolerance
practical Byzantine fault tolerance mechanism is a kind of adoption & quot; Permission to vote, minority subject to majority & quot; The consensus mechanism allows Byzantine fault tolerance, allows strong supervision nodes to participate, has the ability of authority classification, higher performance and lower energy consumption, and each round of bookkeeping will be jointly elected by the whole network nodes, allowing 33% of nodes to do evil, and the fault tolerance rate is 33%. Practical Byzantine fault tolerance is especially suitable for the application scenario of alliance chain<
advantages
will deviate from centralization, the existence of cryptocurrency and reward mechanism will proce Matthew effect, making the poor poorer and the rich richer in the community, achieving high consensus efficiency and realizing high-frequency trading
disadvantages
when only 33% of the nodes in the system are running, the system will stop running
dbft authorizes Byzantine fault tolerance
this mechanism is to use rights to select bookkeeper, Then bookkeepers reach a consensus through Byzantine fault-tolerant algorithm. The core of Byzantine fault tolerance mechanism is to ensure the system's finality to the maximum extent, so that the blockchain can be applied to real financial application scenarios
advantages
Professional bookkeeper can tolerate any type of error, bookkeeping is completed by multiple people, each block has finality, no bifurcation, the reliability of the algorithm has strict mathematical proof
disadvantages
when one-third or more bookkeepers stop working, the system will not be able to provide services, when one-third or more bookkeepers jointly commit crimes, The system may be bifurcated
pool verification pool
based on traditional distributed consistency technology and data verification mechanism
advantages
it can work without cryptocurrency. Based on the mature distributed consistency algorithms (pasox, raft), it realizes second level consensus verification
disadvantages
the degree of decentralization is not as good as bitcoin, which is more suitable for the multi center business model with multi participation
Paxos
this is a traditional distributed consensus algorithm, which is a consensus mechanism based on election leaders. The leader node has absolute authority, and allows strong supervision node to participate, which has high performance and low resource consumption. Generally, all nodes have wired access mechanism, but there is no malicious node in the election process, which is not fault-tolerant< In Paxos algorithm, nodes are divided into three types:
proposer: put forward a proposal and wait for everyone's approval. The client often plays the role
acceptor: responsible for voting on the proposal. Usually, the server plays this role
learner: is informed of the result of the case settlement, and unifies with it, and does not participate in the voting process. Maybe the client or server
Paxos can ensure that the system can reach a consensus when more than 50% of the normal nodes exist
REBO consensus mechanism
REBO consensus algorithm enables a group of nodes to form a consensus based on the special node list. The initial special node list is like a club. To accept a new member, it must be voted by 51% of the members of the club. Consensus follows the & quot; 51% rights;, Outsiders have no influence. Since the club starts with centralization, it will always be, and if it starts to corrupt, shareholders can do nothing. Like bitcoin and peercoin, the reborn system separates shareholders from their voting rights, so it is more centralized than other systems
peercoin
peercoin (PPC) is a combination of proof of pow workload and proof of POS equity. POW is mainly used to issue currency. In the future, with the increase of mining difficulty, the output will decrease, and the system security will be mainly maintained by POS
in the blockchain network, e to different application scenarios, different goals are designed, and different blockchain systems adopt different consensus algorithms. Each consensus algorithm is not perfect and has its own advantages and limitations
blockchain solves the problems of transmitting trusted information and value transfer on untrusted channels, while consensus mechanism solves the problem of how blockchain achieves consistency in distributed scenarios
although the blockchain is still in the early stage of development, and the instry development is still facing some obstacles, the society has recognized the value of the blockchain enough, the pace of blockchain development will never stop, and the instry development will certainly find a way to break through the obstacles.
9. Blockchain is a network system based on hash function calculation and distributed network to realize data encryption, transmission and storage. Its core is no center, and the form is that the network endpoints are distributed, so as to realize the value sharing of data. Its main significance lies in the transformation of Internet from information interconnection to value interconnection, or value Internet<
decentralization was the original purpose of the Internet when it was invented in the 1970s. However, e to the pyramid structure of the real society and the segmentation between regions and departments, decentralization has not really been realized. The importance of decentralization is mentioned in the following aspects:
1. Data security is guaranteed. Because blockchain data is distributed and stored in each endpoint, one or some endpoint data lost or damaged can be recovered from other endpoints. It overcomes the weakness that the current data is mainly stored in the central platform server, once damaged or lost, it cannot be recovered. In addition, the blockchain technology will stamp the time stamp on the data generated each time (it cannot enter the same river), so as to prevent the data from being stolen. There are also asymmetric encryption (two keys: public key and private key) to ensure data security
2. Improve the efficiency of economic activities. Due to the division between different system departments, the data of internal and external doors of the system can not be shared and parallel, and the efficiency of economic activities is very low. For example, import and export trade, in addition to the two sides of the transaction, also involves commodity inspection, customs, banking, transportation, insurance, agency and other departments, the data between these departments to form a block, realize data sharing, can greatly improve the efficiency of the transaction, save transaction costs
3. Breaking the uniqueness of national currency. The currency of each country is issued by the National Central Bank. The blockchain Technology (bitcoin, other digital currencies) breaks the Convention of centralized issuance. In the future, the currency will not be issued by the central bank, but will be generated by the self-organization (value symbol) in the blockchain, and finally realize the unification of world currency
blockchain has other significance and importance. Since it has little to do with decentralization, we will not describe them one by one here.
decentralization was the original purpose of the Internet when it was invented in the 1970s. However, e to the pyramid structure of the real society and the segmentation between regions and departments, decentralization has not really been realized. The importance of decentralization is mentioned in the following aspects:
1. Data security is guaranteed. Because blockchain data is distributed and stored in each endpoint, one or some endpoint data lost or damaged can be recovered from other endpoints. It overcomes the weakness that the current data is mainly stored in the central platform server, once damaged or lost, it cannot be recovered. In addition, the blockchain technology will stamp the time stamp on the data generated each time (it cannot enter the same river), so as to prevent the data from being stolen. There are also asymmetric encryption (two keys: public key and private key) to ensure data security
2. Improve the efficiency of economic activities. Due to the division between different system departments, the data of internal and external doors of the system can not be shared and parallel, and the efficiency of economic activities is very low. For example, import and export trade, in addition to the two sides of the transaction, also involves commodity inspection, customs, banking, transportation, insurance, agency and other departments, the data between these departments to form a block, realize data sharing, can greatly improve the efficiency of the transaction, save transaction costs
3. Breaking the uniqueness of national currency. The currency of each country is issued by the National Central Bank. The blockchain Technology (bitcoin, other digital currencies) breaks the Convention of centralized issuance. In the future, the currency will not be issued by the central bank, but will be generated by the self-organization (value symbol) in the blockchain, and finally realize the unification of world currency
blockchain has other significance and importance. Since it has little to do with decentralization, we will not describe them one by one here.
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