Bitcoin Merkle
Publish: 2021-04-27 07:26:02
1. At the top of Ethereum is DAPP. It exchanges with the smart contract layer through Web3. JS. All smart contracts run on EVM (Ethereum virtual machine) and use RPC calls. Below EVM and RPC are the four core contents of Ethereum, including: blockchain, consensus algorithm, mining and network layer. Except DAPP, all other parts are in the Ethereum client. The most popular Ethereum client is geth (go Ethereum)
2. In order to understand the technical principle of bitcoin, we need to understand two important cryptographic techniques: hash code: it converts a long string into a fixed length string, and its conversion is irreversible, that is, it is impossible to guess the original string from hash code. Sha256 is mainly used in bitcoin protocol
public key system: corresponds to a public key and a private key, keeps the private key in the application and publishes the public key. When Party A transmits information to Party B, it can use Party A's private key to encrypt the information, and Party B can use Party A's public key to decrypt the information, so as to ensure that the third party cannot impersonate Party A to send the information; At the same time, when Party A transmits information to Party B, it is encrypted with Party B's public key and sent to Party B, and then Party B decrypts it with his own private key, so as to ensure that the third party cannot eavesdrop on the communication between the two people. RSA is the most common public key system, but the lliptic curve digital signature algorithm is used in bitcoin protocol. What's the difference between cash and bank account? Bitcoin is an electronic currency in BTC. In this article, it is also used to refer to the whole bitcoin system. Like opening an account in a bank, the corresponding concept in bitcoin is address. Everyone can have one or more bitcoin addresses, which are used to pay and collect money. Each address is a string that starts with 1. For example, I have two bitcoin accounts, and. A bitcoin account is uniquely determined by a pair of public key and private key. To save the account, you only need to save the private key file. Unlike bank accounts, banks keep all transaction records and maintain the book balance of each account, while bitcoin's transaction records are jointly maintained by the whole P2P network through a pre agreed protocol. How much money is in my account address? Although the current account balance can be seen by bitcoin software, unlike banks, there is no place to maintain the book balance of each address. It can only calculate the account balance in real time through all historical transactions. How do I pay? When I pay from address a to address B of the other party, the payment amount is e. at this time, both parties will announce the transaction information to each network node, telling address a to pay to address B, and the payment amount is e. In order to prevent the third party from forging the transaction information, the transaction information will be encrypted with the private key of address A. at this time, the network node receiving the transaction information can use the public key of address a to verify that the transaction information is indeed sent by address a. Of course, trading software will help us do these things, we just need to input the relevant parameters in the software. What will the network node do after receiving the transaction information? This is the most important part of the bitcoin system, which needs to be elaborated. For the sake of simplicity, only bitcoin protocol has been implemented. In the current version, each network node will save all transaction information synchronously. There are two kinds of transaction information in history, one is & quot; Verified & quot; The transaction information, that is, the verified transaction information, is stored in a series of "blocks". Each & quot; block" Is the previous & quot; bock" The ID of each block is the hash code of the hash code of the block and the new transaction information (see an actual block). The other category refers to those who also & quot; Unverified & quot; The transaction information just paid above belongs to this category. When a network node receives new unverified transaction information (possibly more than one), it can calculate the book balance of each address at that time because the node keeps all the transaction information in history, so it can calculate whether the transaction information is valid, that is, whether there is enough balance in the payment account. After eliminating the invalid transaction information, it first takes out the last & quot; block" Then, the unverified transaction information is combined with the ID, and a verification code is added to form a new "block". It needs a lot of calculation to build a new block, because it needs to calculate the verification code, so that the above combination becomes a block, that is, the first several bits of the hash code of the block are 1. At present, the first 13 bits need to be 1 (generally, the specific method is uncertain), which means that if the block is generated by enumeration method, the average number of enumerations is 16 ^ 13. Using CPU resources to generate a block is called "gold mining", because the proction of the block will get a certain reward, and the reward information has been included in the block. When a network node generates a new block, it will broadcast to other network nodes. However, this network block may not be accepted by the network, because it is possible that other network nodes have proced the block earlier. Only the earliest block or the block with the largest number of subsequent blocks is valid, and the remaining blocks are no longer used as the initial blocks of the next block. How does the other party confirm that the payment is successful? When the payment information is distributed to the network node, the network node begins to calculate whether the transaction is valid (that is, whether the account balance is enough to pay), and attempts to generate blocks containing the transaction information. When six blocks (one direct block and five subsequent blocks) contain the transaction information, the transaction information is considered "verified", so that the transaction is formally confirmed, and the other party can confirm the successful payment. A possible problem is that I will pay the balance of address a to address B, and at the same time pay to address C. If I only verify that the single comparison transaction is valid. At this point, my way of cheating is to generate six blocks including B to B and six blocks including C to C before the truth is revealed. Because I need a very long CPU time to generate a block, compared with the whole network, the probability of my cheating success is very small. What is the motivation of network nodes to proce blocks? As can be seen from the above description, in order to make the transaction information effective, the network node needs to generate 1 and 5 subsequent blocks to contain the transaction information, and such block generation is very CPU intensive. How to let other network nodes help to proce blocks as soon as possible? The answer is very simple. The agreement stipulates that BTC will be rewarded for the address where the block is proced, as well as the Commission promised by both parties. At present, the reward for procing a block is 50btc, which will be halved every four years in the future. For example, the reward will be 25btc from 2013 to 2016. Is the transaction anonymous? Yes, and No. All bitcoin transactions are visible. We can check all transaction records of each account, such as mine. But what's different from the banking monetary system is that everyone's account itself is anonymous, and everyone can open many accounts. In general, anonymity is not as good as it claims. But bitcoin has another advantage in doing black market trading: it can't be frozen. Even if the police trace a bitcoin address, there is nothing they can do unless they trace the computer used by the exchange based on the Internet address. How to ensure that bitcoin does not depreciate? Generally speaking, in the case of equivalent trading activities, the value of money is inversely proportional to the amount of money issued. Unlike the traditional money market, the central bank can determine the amount of money issued. Bitcoin does not have a central issuing institution. Only by procing blocks can we get a certain amount of BTC currency. Therefore, bitcoin's new amount of money depends on: 1. The speed of procing blocks: bitcoin's agreement stipulates that the difficulty of procing blocks is fixed at an average of 2016 every two weeks, about 10 minutes. Moore's law of doubling CPU speed every 18 months will not speed up the proction of block. 2. The number of rewards for block proction: at present, 50 BTC is awarded for each block proced, which is halved every four years. In 2013, 25 BTC is awarded, and in 2017, 12.5 BTC is awarded. Considering the above two factors, bitcoin's currency issuing speed is not controlled by any single node in the network. Its protocol makes the currency stock known in advance, and the maximum stock is only 21 million BTC
public key system: corresponds to a public key and a private key, keeps the private key in the application and publishes the public key. When Party A transmits information to Party B, it can use Party A's private key to encrypt the information, and Party B can use Party A's public key to decrypt the information, so as to ensure that the third party cannot impersonate Party A to send the information; At the same time, when Party A transmits information to Party B, it is encrypted with Party B's public key and sent to Party B, and then Party B decrypts it with his own private key, so as to ensure that the third party cannot eavesdrop on the communication between the two people. RSA is the most common public key system, but the lliptic curve digital signature algorithm is used in bitcoin protocol. What's the difference between cash and bank account? Bitcoin is an electronic currency in BTC. In this article, it is also used to refer to the whole bitcoin system. Like opening an account in a bank, the corresponding concept in bitcoin is address. Everyone can have one or more bitcoin addresses, which are used to pay and collect money. Each address is a string that starts with 1. For example, I have two bitcoin accounts, and. A bitcoin account is uniquely determined by a pair of public key and private key. To save the account, you only need to save the private key file. Unlike bank accounts, banks keep all transaction records and maintain the book balance of each account, while bitcoin's transaction records are jointly maintained by the whole P2P network through a pre agreed protocol. How much money is in my account address? Although the current account balance can be seen by bitcoin software, unlike banks, there is no place to maintain the book balance of each address. It can only calculate the account balance in real time through all historical transactions. How do I pay? When I pay from address a to address B of the other party, the payment amount is e. at this time, both parties will announce the transaction information to each network node, telling address a to pay to address B, and the payment amount is e. In order to prevent the third party from forging the transaction information, the transaction information will be encrypted with the private key of address A. at this time, the network node receiving the transaction information can use the public key of address a to verify that the transaction information is indeed sent by address a. Of course, trading software will help us do these things, we just need to input the relevant parameters in the software. What will the network node do after receiving the transaction information? This is the most important part of the bitcoin system, which needs to be elaborated. For the sake of simplicity, only bitcoin protocol has been implemented. In the current version, each network node will save all transaction information synchronously. There are two kinds of transaction information in history, one is & quot; Verified & quot; The transaction information, that is, the verified transaction information, is stored in a series of "blocks". Each & quot; block" Is the previous & quot; bock" The ID of each block is the hash code of the hash code of the block and the new transaction information (see an actual block). The other category refers to those who also & quot; Unverified & quot; The transaction information just paid above belongs to this category. When a network node receives new unverified transaction information (possibly more than one), it can calculate the book balance of each address at that time because the node keeps all the transaction information in history, so it can calculate whether the transaction information is valid, that is, whether there is enough balance in the payment account. After eliminating the invalid transaction information, it first takes out the last & quot; block" Then, the unverified transaction information is combined with the ID, and a verification code is added to form a new "block". It needs a lot of calculation to build a new block, because it needs to calculate the verification code, so that the above combination becomes a block, that is, the first several bits of the hash code of the block are 1. At present, the first 13 bits need to be 1 (generally, the specific method is uncertain), which means that if the block is generated by enumeration method, the average number of enumerations is 16 ^ 13. Using CPU resources to generate a block is called "gold mining", because the proction of the block will get a certain reward, and the reward information has been included in the block. When a network node generates a new block, it will broadcast to other network nodes. However, this network block may not be accepted by the network, because it is possible that other network nodes have proced the block earlier. Only the earliest block or the block with the largest number of subsequent blocks is valid, and the remaining blocks are no longer used as the initial blocks of the next block. How does the other party confirm that the payment is successful? When the payment information is distributed to the network node, the network node begins to calculate whether the transaction is valid (that is, whether the account balance is enough to pay), and attempts to generate blocks containing the transaction information. When six blocks (one direct block and five subsequent blocks) contain the transaction information, the transaction information is considered "verified", so that the transaction is formally confirmed, and the other party can confirm the successful payment. A possible problem is that I will pay the balance of address a to address B, and at the same time pay to address C. If I only verify that the single comparison transaction is valid. At this point, my way of cheating is to generate six blocks including B to B and six blocks including C to C before the truth is revealed. Because I need a very long CPU time to generate a block, compared with the whole network, the probability of my cheating success is very small. What is the motivation of network nodes to proce blocks? As can be seen from the above description, in order to make the transaction information effective, the network node needs to generate 1 and 5 subsequent blocks to contain the transaction information, and such block generation is very CPU intensive. How to let other network nodes help to proce blocks as soon as possible? The answer is very simple. The agreement stipulates that BTC will be rewarded for the address where the block is proced, as well as the Commission promised by both parties. At present, the reward for procing a block is 50btc, which will be halved every four years in the future. For example, the reward will be 25btc from 2013 to 2016. Is the transaction anonymous? Yes, and No. All bitcoin transactions are visible. We can check all transaction records of each account, such as mine. But what's different from the banking monetary system is that everyone's account itself is anonymous, and everyone can open many accounts. In general, anonymity is not as good as it claims. But bitcoin has another advantage in doing black market trading: it can't be frozen. Even if the police trace a bitcoin address, there is nothing they can do unless they trace the computer used by the exchange based on the Internet address. How to ensure that bitcoin does not depreciate? Generally speaking, in the case of equivalent trading activities, the value of money is inversely proportional to the amount of money issued. Unlike the traditional money market, the central bank can determine the amount of money issued. Bitcoin does not have a central issuing institution. Only by procing blocks can we get a certain amount of BTC currency. Therefore, bitcoin's new amount of money depends on: 1. The speed of procing blocks: bitcoin's agreement stipulates that the difficulty of procing blocks is fixed at an average of 2016 every two weeks, about 10 minutes. Moore's law of doubling CPU speed every 18 months will not speed up the proction of block. 2. The number of rewards for block proction: at present, 50 BTC is awarded for each block proced, which is halved every four years. In 2013, 25 BTC is awarded, and in 2017, 12.5 BTC is awarded. Considering the above two factors, bitcoin's currency issuing speed is not controlled by any single node in the network. Its protocol makes the currency stock known in advance, and the maximum stock is only 21 million BTC
3. For example, there are only 10 gold in the world. Use the gold as currency. The more people you use, the more valuable it is
4.
Short refers to selling positions, can also be called use, sell a certain type of currency loans, bullish. Do long: do and refer to the multi warehouse, can also be called Lido, also known as multi warehouse. Buy some kind of loan currency and be bearish
Long means that the price will rise after estimation, so buy the contract and sell it at sky high price after the price rises in the future. Net profit. Short selling means that the potential will fall after estimation, so sell the contract and buy the contract at a low price after the price falls in the future. Net profit2. For hedging: to be long means to evade or wash away the risk of proct cost expansion caused by future price rise, and lock up the cost in advance. Short selling means to evade or wash away the risk of profit rection caused by the price decline in the future, and lock in the profit ahead of time
extended data
burst, under some special conditions, the customer's equity in the investor's margin account is negative. When the market changes greatly, if most of the funds in the margin account of investors are occupied by trading margin, and the trading direction is opposite to the market trend, it is easy to burst e to the leverage effect of margin trading
if the position explosion leads to the deficit and is caused by the investors, the investors need to make up the deficit, otherwise they will face legal recourse. The bigger the leverage is, the closer it is to the burst. We should be cautious when adding any leverage
5. Bitcoin was born in a paper in 2008
a person signed by Nakamoto Tsui has put forward a revolutionary idea: let's create a currency that is not controlled by the government or anyone else! This idea is crazy: there is no asset support behind a string of figures, and no one is responsible for it. How can anyone accept it when you pay it to the other party as money
Merkle tree
looks like a binary tree, but this is the lower two nodes. Take the hash value to get the upper node. Just remember the root node to detect whether the whole tree has been tampered
the root hash value is stored in the block header, and the transaction process is stored in the block body. All nodes include block header and block body, but light nodes (such as bitcoin wallets on mobile phones) only include block header. This tree can prove that a transaction has been written into the blockchain
3. Consensus agreement
two issues should be paid attention to in decentralized currency:
1. Who can issue digital currency: mining
2. How to verify the legitimacy of transactions: blockchain
double spending attack
double spending attack is a major challenge of digital currency
all transactions in bitcoin have input and output. Where does bitcoin come from and where does it go
under normal circumstances, there may be two bifurcations, because two nodes obtain the bookkeeping right at the same time, and the two nodes package the block and calculate the random number at the same time. At this time, the two bifurcations will coexist temporarily until one of the blocks finds the next block first, which becomes the longest legal chain, and the other one is discarded<
Sybil attack
a malicious node keeps generating accounts. If the total number of accounts exceeds half of the total accounts, it obtains the control of the blockchain
consensus protocol in bitcoin
some nodes are malicious, and most nodes are good
idea 1: pack some transactions into blocks as candidate blocks, let each block vote, and write them into the blockchain if they pass
No, because some malicious nodes have been publishing blocks containing malicious transactions, and they have been voting and occupying resources. And some nodes don't vote<
idea 2: vote not by the number of accounts, but by computing power. Each node can generate legal transactions and put them into the block. These nodes start to try random numbers until H (block header) ≤ target is found, then this node has the right to account
the only way to generate bitcoin
coinbase transaction. There is no need to point out the source of the currency. If you have the bookkeeping right, you will get a reward< br />
50BTC-> 25BTC-> 12.5btc, the reward will be halved for every 210000 bitcoins
the process of bitcoin competing for bookkeeping rights is called mining. The node competing for bookkeeping right is called miner.
a person signed by Nakamoto Tsui has put forward a revolutionary idea: let's create a currency that is not controlled by the government or anyone else! This idea is crazy: there is no asset support behind a string of figures, and no one is responsible for it. How can anyone accept it when you pay it to the other party as money
Merkle tree
looks like a binary tree, but this is the lower two nodes. Take the hash value to get the upper node. Just remember the root node to detect whether the whole tree has been tampered
the root hash value is stored in the block header, and the transaction process is stored in the block body. All nodes include block header and block body, but light nodes (such as bitcoin wallets on mobile phones) only include block header. This tree can prove that a transaction has been written into the blockchain
3. Consensus agreement
two issues should be paid attention to in decentralized currency:
1. Who can issue digital currency: mining
2. How to verify the legitimacy of transactions: blockchain
double spending attack
double spending attack is a major challenge of digital currency
all transactions in bitcoin have input and output. Where does bitcoin come from and where does it go
under normal circumstances, there may be two bifurcations, because two nodes obtain the bookkeeping right at the same time, and the two nodes package the block and calculate the random number at the same time. At this time, the two bifurcations will coexist temporarily until one of the blocks finds the next block first, which becomes the longest legal chain, and the other one is discarded<
Sybil attack
a malicious node keeps generating accounts. If the total number of accounts exceeds half of the total accounts, it obtains the control of the blockchain
consensus protocol in bitcoin
some nodes are malicious, and most nodes are good
idea 1: pack some transactions into blocks as candidate blocks, let each block vote, and write them into the blockchain if they pass
No, because some malicious nodes have been publishing blocks containing malicious transactions, and they have been voting and occupying resources. And some nodes don't vote<
idea 2: vote not by the number of accounts, but by computing power. Each node can generate legal transactions and put them into the block. These nodes start to try random numbers until H (block header) ≤ target is found, then this node has the right to account
the only way to generate bitcoin
coinbase transaction. There is no need to point out the source of the currency. If you have the bookkeeping right, you will get a reward< br />
50BTC-> 25BTC-> 12.5btc, the reward will be halved for every 210000 bitcoins
the process of bitcoin competing for bookkeeping rights is called mining. The node competing for bookkeeping right is called miner.
6. Hello, questioner:
in the very early days, when the computing power of bitcoin was very low, the computer could also carry out a lot of calculations according to the algorithm to "mine" bitcoin
when users "mine" bitcoin, they need to search for 64 bit numbers by computer, and then compete with other gold miners by repeatedly solving puzzles to provide the required numbers for the bitcoin network. If the user's computer successfully creates a group of numbers, they will get the bitcoin awarded by the block. However, e to the rising value of bitcoin, the number of users of bitcoin mining is very large. There are millions of professional mining machines mining at the same time, and the output of bitcoin is very limited every 10 minutes. As a result, tens of millions of people scramble for a block. Therefore, if you use personal computers to mine alone, you may not be able to grab a block in a whole year, People came up with a method of group mining, so the mining pool was born. There are a lot of users who play after mining
I hope you will adopt it.
in the very early days, when the computing power of bitcoin was very low, the computer could also carry out a lot of calculations according to the algorithm to "mine" bitcoin
when users "mine" bitcoin, they need to search for 64 bit numbers by computer, and then compete with other gold miners by repeatedly solving puzzles to provide the required numbers for the bitcoin network. If the user's computer successfully creates a group of numbers, they will get the bitcoin awarded by the block. However, e to the rising value of bitcoin, the number of users of bitcoin mining is very large. There are millions of professional mining machines mining at the same time, and the output of bitcoin is very limited every 10 minutes. As a result, tens of millions of people scramble for a block. Therefore, if you use personal computers to mine alone, you may not be able to grab a block in a whole year, People came up with a method of group mining, so the mining pool was born. There are a lot of users who play after mining
I hope you will adopt it.
7.
Bitcoin is actually a useless string of numbers, but it is recognized as useful, just like diamonds, antiques, calligraphy and paintings, game skin and so on. They can't be eaten or used, but we will recognize their value
"mining" just allows more people to participate in the construction of blockchain network. Is it really good that so many electricity charges are used to "calculate" a series of virtual values? Bitcoin is not a hedge. The price of bitcoin fluctuates greatly. Speculation on bitcoin may become rich overnight or become poor overnight. Bitcoin is not as safe as it claims. In 2014, the world's largest bitcoin trading website, mtgox, was hacked and went bankrupt, and the $467 million worth of bitcoin evaporated instantly. Criminals use it to launder money, evade taxes and so on. It is also quite difficult for the government to investigate. The above personal opinions are welcome to be criticized and corrected. Agree with me, please click like before you go, thank you! Like me, please pay attention to me, thank you again
8. There are mainly two kinds of bitcoin algorithms, which are elliptic curve digital signature algorithm and sha256 hash algorithm
elliptic curve digital signature algorithm is mainly used in the generation process of bitcoin public key and private key, which is the cornerstone of bitcoin system. SHA-256 hash algorithm is mainly used in the workload proof mechanism of bitcoin
the principle of bitcoin generation is the special solution generated by complex operation, and mining is the process of finding the special solution. However, the total number of bitcoin is only 21 million, and with the continuous mining of bitcoin, the more difficult it will be to proce bitcoin, and the cost of acquiring bitcoin may be higher than the price of bitcoin itself
the bitcoin block consists of a block header and the transaction list contained in the block. The size of the block header is 80 bytes, which is composed of 4-byte version number, 32 byte hash value of the previous block, 32 byte Merkle root hash, 4-byte timestamp (current time), 4-byte current difficulty value and 4-byte random number. A block header with a fixed length of 80 bytes is the input string used to prove the workload of bitcoin. Constantly change the random number in the block header, that is, the value of nonce, and do double sha256 operation on the block header after each change, and compare the result value with the target value of the current network. If it is less than the target value, the problem is solved successfully, and the workload is proved to be complete
the essence of bitcoin is actually the unique solution of a set of equations generated by a bunch of complex algorithms. Bitcoin is the first distributed virtual currency in the world, which has no specific distribution center. The network of bitcoin is composed of all users, because there is no center to ensure the security of data.
elliptic curve digital signature algorithm is mainly used in the generation process of bitcoin public key and private key, which is the cornerstone of bitcoin system. SHA-256 hash algorithm is mainly used in the workload proof mechanism of bitcoin
the principle of bitcoin generation is the special solution generated by complex operation, and mining is the process of finding the special solution. However, the total number of bitcoin is only 21 million, and with the continuous mining of bitcoin, the more difficult it will be to proce bitcoin, and the cost of acquiring bitcoin may be higher than the price of bitcoin itself
the bitcoin block consists of a block header and the transaction list contained in the block. The size of the block header is 80 bytes, which is composed of 4-byte version number, 32 byte hash value of the previous block, 32 byte Merkle root hash, 4-byte timestamp (current time), 4-byte current difficulty value and 4-byte random number. A block header with a fixed length of 80 bytes is the input string used to prove the workload of bitcoin. Constantly change the random number in the block header, that is, the value of nonce, and do double sha256 operation on the block header after each change, and compare the result value with the target value of the current network. If it is less than the target value, the problem is solved successfully, and the workload is proved to be complete
the essence of bitcoin is actually the unique solution of a set of equations generated by a bunch of complex algorithms. Bitcoin is the first distributed virtual currency in the world, which has no specific distribution center. The network of bitcoin is composed of all users, because there is no center to ensure the security of data.
9. Bitcoin calculation requires the following parameters:
1. Version of block
2. Hash value of the previous block: prev_ Hash
3. The hash tree value of the transaction record to be written: Merkle_ Root
4. Update time: ntime
5. Current difficulty: nbits
the process of mining is to find x to make
sha256 (version + prev)_ hash + merkle_ root + ntime + nbits + x )) < Target
the range of X in the above formula is 0 ~ 2 ^ 32, which can be calculated according to the current difficulty. In addition to x, you can also try to change Merkle_ Root and ntime. Because of the hash feature, finding such an X can only be brute force search
once calculator a finds x, it can broadcast a new block, and other clients will verify whether the block published by calculator a is legal
if the published block is accepted, the first transaction in each block must be to send the newly generated 25 bitcoins to an address. Of course, calculator a will set this address to the address owned by calculator a to get the 25 bitcoins.
1. Version of block
2. Hash value of the previous block: prev_ Hash
3. The hash tree value of the transaction record to be written: Merkle_ Root
4. Update time: ntime
5. Current difficulty: nbits
the process of mining is to find x to make
sha256 (version + prev)_ hash + merkle_ root + ntime + nbits + x )) < Target
the range of X in the above formula is 0 ~ 2 ^ 32, which can be calculated according to the current difficulty. In addition to x, you can also try to change Merkle_ Root and ntime. Because of the hash feature, finding such an X can only be brute force search
once calculator a finds x, it can broadcast a new block, and other clients will verify whether the block published by calculator a is legal
if the published block is accepted, the first transaction in each block must be to send the newly generated 25 bitcoins to an address. Of course, calculator a will set this address to the address owned by calculator a to get the 25 bitcoins.
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