PPC Dot Coin mobile phone mining
Publish: 2021-05-14 19:37:43
1. digital currency is a kind of legal tender, which must be issued by the central bank. Both digital gold coin and cryptocurrency belong to digital currency, which is not a network virtual currency, because it is not limited to virtual space, but is often used for real goods and services transactions, such as bitcoin, Wright coin, bitstock, etc. at present, there are thousands of digital currencies issued around the world
the digital currency launched by the central bank is a national sovereign currency, which is based on the digitalization of RMB. This is a piece of data generated by a complex algorithm, which contains blockchain and encryption technology, making it unique. The payment of Alipay and WeChat is not digital money, but only based on the payment realized by electronic accounts. Compared with the current pattern of "payment transfer collection" with the help of third-party payment, what digital currency needs to achieve is "decentralization", that is, to cancel the transfer link and directly hand over the money from the payer's account to the payee, so as to rece the payment cost in currency circulation
types of digital currency
according to different issuing or consensus mechanisms, it can be divided into four categories:
1, proof of work (POW)
proof of work. The system rewards are obtained through the mining of computing power to complete the issuance and distribution of currency. More work, more gain. Such as bitcoin, lightcoin (LTC)
the advantage is that the mining cost can form a monetary price support to a certain extent, and the disadvantage is that energy consumption and environmental protection are criticized< 2. Proof of stake (POS). Allocate the newly generated currency or interest according to the amount and time of cryptocurrency you hold. Such as dash and Neo
compared with pow, POS is more energy-saving, but it increases the security risk
3. The evolution scheme of delegated proof of stake (dpos)
POS. Similar to the voting mechanism of the board of directors, through the election of representatives to vote and make decisions, n accounting nodes are elected to create, verify, sign and supervise each other. Such as the grapefruit coin (EOS)
the advantage is high efficiency, but the problem is that it presents a semi centralized state
4. POW + POS hybrid mechanism
POW is mainly used to issue currency, and POS is used to maintain the system. For example, PPC
according to the project type, it can also be divided into four categories:
1. Currency category
digital currency issued for the purpose of transfer, payment and value storage. For example, bitcoin, bitcoin cash (BCH), Monroe (XmR), and grin
2. Public chain currency, that is, the digital currency issued by public chain projects, is generally the "fuel" for the application projects to run on the public chain. Such as eth, grapefruit coin, TRX and ont
3. Application token, that is, digital currency issued by decentralized application projects, is equivalent to equity or points. For example, OMG (payment application), GXC (data application), 1st (game application)
4. Platform currency, that is, the digital currency issued by the digital currency exchange, is equivalent to equity, points or fuel. For example, BNB, HT and okb.
the digital currency launched by the central bank is a national sovereign currency, which is based on the digitalization of RMB. This is a piece of data generated by a complex algorithm, which contains blockchain and encryption technology, making it unique. The payment of Alipay and WeChat is not digital money, but only based on the payment realized by electronic accounts. Compared with the current pattern of "payment transfer collection" with the help of third-party payment, what digital currency needs to achieve is "decentralization", that is, to cancel the transfer link and directly hand over the money from the payer's account to the payee, so as to rece the payment cost in currency circulation
types of digital currency
according to different issuing or consensus mechanisms, it can be divided into four categories:
1, proof of work (POW)
proof of work. The system rewards are obtained through the mining of computing power to complete the issuance and distribution of currency. More work, more gain. Such as bitcoin, lightcoin (LTC)
the advantage is that the mining cost can form a monetary price support to a certain extent, and the disadvantage is that energy consumption and environmental protection are criticized< 2. Proof of stake (POS). Allocate the newly generated currency or interest according to the amount and time of cryptocurrency you hold. Such as dash and Neo
compared with pow, POS is more energy-saving, but it increases the security risk
3. The evolution scheme of delegated proof of stake (dpos)
POS. Similar to the voting mechanism of the board of directors, through the election of representatives to vote and make decisions, n accounting nodes are elected to create, verify, sign and supervise each other. Such as the grapefruit coin (EOS)
the advantage is high efficiency, but the problem is that it presents a semi centralized state
4. POW + POS hybrid mechanism
POW is mainly used to issue currency, and POS is used to maintain the system. For example, PPC
according to the project type, it can also be divided into four categories:
1. Currency category
digital currency issued for the purpose of transfer, payment and value storage. For example, bitcoin, bitcoin cash (BCH), Monroe (XmR), and grin
2. Public chain currency, that is, the digital currency issued by public chain projects, is generally the "fuel" for the application projects to run on the public chain. Such as eth, grapefruit coin, TRX and ont
3. Application token, that is, digital currency issued by decentralized application projects, is equivalent to equity or points. For example, OMG (payment application), GXC (data application), 1st (game application)
4. Platform currency, that is, the digital currency issued by the digital currency exchange, is equivalent to equity, points or fuel. For example, BNB, HT and okb.
2. Digital currency is an alternative currency in the form of electronic currency. Both digital gold coin and cryptocurrency belong to digital currency. Digital currency is an unregulated and digital currency, which is usually issued and managed by developers and accepted and used by members of a specific virtual community.
3. Blockchain is a decentralized distributed ledger system, which can be used to register and issue digital assets, property rights certificates, points, etc., and transfer, pay and trade in a point-to-point manner. Compared with the traditional centralized ledger system, blockchain system has the advantages of complete disclosure, tamper proof, multiple payment prevention, and does not rely on any trusted third party
e to the high network delay in peer-to-peer network, the transaction order observed by each node can not be completely consistent. Therefore, the blockchain system needs to design a mechanism to reach a consensus on the sequence of transactions that occur in the same time. This algorithm to reach consensus on the order of transactions in a time window is called consensus mechanism
-- chainknow
e to the high network delay in peer-to-peer network, the transaction order observed by each node can not be completely consistent. Therefore, the blockchain system needs to design a mechanism to reach a consensus on the sequence of transactions that occur in the same time. This algorithm to reach consensus on the order of transactions in a time window is called consensus mechanism
-- chainknow
4. 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.
5.
8421BCD code uses 4-bit binary code to represent decimal value. The weights from high bit to low bit are 8, 4, 2 and 1 respectively. As long as the weights corresponding to each 4-bit binary code are added, the corresponding decimal number can be obtained. Such as binary 10010111bcd code into decimal is: 97
The coding technique of BCD code is most commonly used in the design of accounting system, because the accounting system often needs to accurately calculate a long number string. Compared with other coding methods, BCD coding can not only save the accuracy of numerical value, but also save the time of floating-point operation BCD code is also called binary code decimal number. BCD code can be divided into weighted code and non weighted code. The common weighted BCD codes are 8421, 2421 and 5421, and the unauthorized BCD codes are the remainder 3, the remainder 3 cyclic code and the gray code8421BCD code is the most basic and commonly used BCD code, which is similar to four bit natural binary code. It only selects the first 10 groups of four bit binary code, that is, 0000 ~ 1001 represents 0 ~ 9 of decimal number, and the remaining six groups are not used
6. If you don't say it's 8421, just turn it. The 134
BCD code of decimal system represents one decimal number with four binary numbers. 8421 code is usually used (there are others, such as 2421 code and the remaining 3 code)
let's use code 8421 to explain
four digit binary. They correspond to 8, 4, 2 and 1 respectively
for example: 1010, then the corresponding number is 8.021, and the total number is 11
for example: 0101, then the corresponding number is 0.401, and the total number is 5
in the same way,
2421 corresponds to 2, 4, 2, and 1
is 8421 used for the remaining 3 codes, but after using it, it needs to be reced by 3
BCD code of decimal system represents one decimal number with four binary numbers. 8421 code is usually used (there are others, such as 2421 code and the remaining 3 code)
let's use code 8421 to explain
four digit binary. They correspond to 8, 4, 2 and 1 respectively
for example: 1010, then the corresponding number is 8.021, and the total number is 11
for example: 0101, then the corresponding number is 0.401, and the total number is 5
in the same way,
2421 corresponds to 2, 4, 2, and 1
is 8421 used for the remaining 3 codes, but after using it, it needs to be reced by 3
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