Virtual currency algorithm statistics
The total number of bitcoins is 21 million
in 2009, when bitcoin was born, block reward was 50 bitcoins. Ten minutes after its birth, the first 50 bitcoins were generated, and the total amount of money at this time is 50. Then bitcoin grew at a rate of about 50 every 10 minutes. When the total amount reaches 10.5 million (50% of 21 million), the block reward will be halved to 25
when the total amount reaches 15.75 million (5.25 million new output, i.e. 50% of 1050), the block reward will be further halved to 12.5. 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 about 21 million
extended data
monetary characteristics
1. Decentralization: bitcoin is the first distributed virtual currency, and the whole network is composed of users without a central bank. Decentralization is the guarantee of bitcoin's security and freedom
2. Global circulation: bitcoin can be managed on any computer connected to the Internet. No matter where you are, anyone can dig, buy, sell or collect bitcoin
3. Exclusive ownership: private key is needed to control bitcoin, which can be stored in any storage medium in isolation. No one can get it except the user himself
4. Low transaction cost: bitcoin can be remitted free of charge, but a transaction fee of about 1 bitfen will be charged for each transaction to ensure faster transaction execution
5, no hidden cost: as a means of payment from a to B, bitcoin has no cumbersome limit of quota and proceres. If you know the other party's bitcoin address, you can pay
6. Cross platform mining: users can explore the computing power of different hardware on many platforms
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
litecoin (LTC), released on October 7, 2011, is the most valuable counterfeit coin at present, accounting for about 2% of BTC's market value. The current unit price is US $2.31, with a total currency value of US $38 million
this is also a distributed (decentralized) digital currency. Unlike the sha256 mining algorithm used by bitcoin, LTC adopts scrypt algorithm. Scrypt algorithm uses sha256 as its subroutine, and scrypt itself needs a lot of memory. Each hash is used as the seed of the input, and then it needs a lot of memory to store another pseudo-random sequence to generate the pseudo-random points of the sequence and output the hash value. In the mining of BTC (bitcoin), it is not enough to rely on simple graphics card mining (it takes about ten to dozens of days to dig a BTC with general configuration graphics card). The emergence of various expensive mining machines has raised the threshold for ordinary people to get BTC through mining, while LTC has certain advantages in using PC graphics card mining This passage comes from Zhihu.)
compared with BTC, litecain has made a little improvement in technology. If BTC is gold now, LTC is silver for the time being
the biggest advantage of litecoin is that it can confirm the authenticity faster. The virtual currency is designed and maintained by Charles Lee. Bitcoin transactions need to be verified, and the average verification time is more than 10 minutes. Most transaction websites need 1 hour to verify. The average transaction confirmation time of liteoin is 2.5 minutes. Developers claim that shortening the verification time increases the practicability of virtual currency. The bitcoin mining efficiency of customized machine and AMD GPU is the highest, making it almost unprofitable for miners using CPU mining. Litecain's mining excludes GPUs and custom processors, so it doesn't rely too much on a small number of professional miners
ppcoin
ppcoin (PPC) was released on August 19, 2012, which has improved the original technology of BTC. Use proof of make and add the concept of coin age
ppcoin is a bifurcated project of bitcoin, which aims to achieve energy efficiency and maintain the best performance of the original bitcoin as far as possible. The unit price of ppcoin is US $0.22 and the total currency value is US $4 million
ppcoin does not have a fixed upper limit of money supply, but it does not mean that ppcoin has obvious inflation compared with bitcoin. Bitcoin can be compared to gold. The annual inflation rate of gold is about 1-3%. Although gold has no known upper limit of money supply, we still know that it is a reliable scarce commodity
ppcoin has two types of casting: work certificate and equity certificate. The coinage rate of working proof is affected by Moore's law, which depends on the doubling of our working proof ability. What we all know is that Moore's law will eventually come to an end. By then, the ppcoin of inflation may be close to the gold level. The annual maximum inflation rate of certificate of equity is 1%. At the same time, ppcoin's transaction costs were destroyed to fight inflation. So on the whole, the coin design of ppcoin is still a very low inflation design in the future, which can be comparable with bitcoin<
ppcoin's reward is similar to lottery, which will determine the winning probability according to the number of ppcoin held by miners. Sunny king, one of the founders, said that their design is based on a new concept of long-term energy efficiency
terracoin
terracoin (TRC) was released on October 26, 2012, with a total currency of 42 million. The speed of each block is 2 minutes, slightly faster than LTC. There is not much special in technology, similar to the proction of BTC halved every four years
however, the operation team seems to have a strong business background and may be better than other bitcoins in circulation. The development of virtual currency is getting more and more attention. Now some teams with business background will accelerate the development of virtual currency
namecoin
namecoin is a distributed domain name system based on bitcoin technology. Its principle is the same as bitcoin. The first release date of this open source software is April 18, 2011
namecoin is generated from an original block which is different from bitcoin's main trading block. It uses a new blockchain, which is independent of bitcoin's blockchain. Because it is based on bitcoin, the security, distribution, robustness, encryption and migration of domain names are guaranteed mathematically. You can dig bitcoin and namecoin at the same time
this project was discussed and proposed by bitdns, which is mainly dissatisfied with the defects of DNS. The only top-level domain name of namecoin is. Bit. It costs namecoin to register a. Bit domain name.
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.
in addition to bitcoin, there are also well-known digital currencies such as Leyte coin and Ruitai coin.
some platforms are calculated by 24 hours, some by day, and some by average price. Specific algorithm or to ask the relevant trading platform, this is no standard answer
there are risks in digital currency investment, especially since digital currency has recently entered a bear market, investment should be more cautious. It is better to invest in mainstream digital currencies such as bitcoin, bitcoin cash and wikilink, which have passed the test of the market.