Bitcoin algorithm AI
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
the concept of bitcoin was first proposed by Nakamoto in 2009. According to Nakamoto's idea, the open source software was designed and released, and the P2P network on it was built. Bitcoin is a kind of P2P digital currency. Point to point transmission means a decentralized payment system. Unlike most currencies, bitcoin does not rely on specific currency institutions. It is generated by a large number of calculations based on specific algorithms. Bitcoin economy uses the distributed database composed of many nodes in the whole P2P network to confirm and record all transactions, and uses the design of cryptography to ensure the security of all aspects of currency circulation. The decentralized nature of P2P and the algorithm itself can ensure that it is impossible to artificially manipulate the value of bitcoin by mass manufacturing. The design based on cryptography can make bitcoin only be transferred or paid by the real owner. This also ensures the anonymity of money ownership and circulation transactions. The biggest difference between bitcoin and other virtual currencies is that the total amount of bitcoin is very limited and it has a strong scarcity. The monetary system used to have no more than 10.5 million in four years, after which the total number will be permanently limited to 21 million. Bitcoin can be cashed and converted into the currency of most countries. Users can use bitcoin to buy some virtual goods, such as clothes, hats and equipment in online games. As long as someone accepts it, they can also use bitcoin to buy real-life goods.
1. Mining can not only proce bitcoin, but also guarantee transaction information
similarly, a mathematical system contains 21 million mathematical problems, so we need to constantly seek the special solution of each mathematical problem through a huge amount of calculation. In addition, the special solution is unique
mining can not only increase the supply of bitcoin money, but also protect the security of bitcoin transactions and prevent fraulent transactions. In terms of process, bitcoin network is a point-to-point payment system, and anyone can trade through the transaction program
in order to ensure that the transaction process is truthfully recorded, the role of "miner" is required to be responsible for recording bitcoin transaction information. The time interval is 10 minutes. The best recorded transaction records among miners will be packaged and stored in a new block, and the corresponding miners will also receive a certain amount of bitcoin rewards
2. The mining process is extremely complex, which is beyond human power
the specific process is as follows. When a miner listens to the transaction, he will first verify the transaction information. The verified transactions will be recorded by miners and stored in their own database. There may be thousands of miners in the world doing the same thing, but every ten minutes, only one miner has the right to create a new block, so that the transaction information recorded by himself can be recognized and stored permanently
next, miners need to fight for the right to keep accounts. This is a competition of computing power. The core of this competition is to use computers to complete a large number of calculation tasks and find a super difficult random number. This random number is the special solution of the equation mentioned in the first paragraph. The miner who calculates the correct random number first wins. According to the rules of the game, the probability of a miner getting the accounting right is directly proportional to the proportion of his computing power in the total computing power of the whole network. In other words, the probability of finding the random number is equivalent to throwing out 100 million dice, and the total number of dice is less than 150 million. Therefore, mining requires a large number of computers, installation of specific algorithm software, repeated operation day and night, not human
3. Bitcoin mining is actually "villagers' bookkeeping"
maybe some netizens still don't understand, let's take an example. In a village, the villagers often borrow money from each other, even if they write a written document, there is a risk of default. Then, every time there is a loan behavior in the village, we will use the village trumpet to inform everyone that all the villagers (miners) will record all the transaction records in their own account books.
Hash algorithm maps any length of binary value to a fixed length of smaller binary value, which is called hash value. Hash value is a unique and compact numerical representation of a piece of data. If you hash a piece of plaintext and change only one letter of the paragraph, subsequent hashes will proce different values. It is computationally impossible to find two different inputs with the same hash value
message authentication code (MAC) hash function is usually used with digital signature to sign data, while message detection code (MDC) hash function is used for data integrity
the basic information of bitcoin network is as follows:
all digital currencies that need to be mined have hash values, such as Laite coin, Ruitai coin, doggy coin, Weimeng coin, Diandian coin, Yuanbao coin, etc< br />
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.