Proportion of bitcoin

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

3.

How many cryptocurrencies are there in the world

at present, there are more than 1350 encrypted virtual currencies in circulation in the world. So far, according to the total valuation given by the market price, there are 23 virtual currencies with a valuation of more than US $1 billion, 97 with a value of more than US $100 million, and 573 with a market value of more than US $1 million. All in all, the total market value of virtual currency has exceeded US $5 trillion, of which bitcoin, the earliest invention, accounts for more than half. Players generally admit that bitcoin is not the most effective cryptocurrency, nor is it the most covert and anonymous. However, bitcoin is the first one to appear, so it is the most well-known and popular one

so the question is, does the world need more than 1350 cryptocurrencies

even the players of virtual currency will doubt this. No matter how strange the world is, there cannot be so many virtual currencies. In fact, there are so many new ICO virtual currencies emerging in recent years, which complement the "Crazy" performance of bitcoin in this year. Most of these 1300 kinds of virtual currencies can't be recognized by everyone. From the beginning of ICO, there will be many loopholes that no one will fill. When there is a major adjustment in the virtual currency market, many of them will disappear automatically, which means that no one will go to mine any more

this also leads to a problem. When some of the cryptocurrencies have problems, the entire instry chain and market of virtual currency may be involved like dominoes. Even the strongest bitcoin now will also be involved, because the cryptocurrency, in the final analysis, is supported by the "belief" of players

why is bitcoin worth more than other cryptocurrencies

at the time of writing this article, the total value of bitcoin is about US $270 billion, the total value of cash of bitcoin is about US $31.7 billion, and the market value of bitcoin gold is US $5.17 billion. Since bitcoin cash and bitcoin gold are separated from bitcoin, in a broad sense, they should be counted as a part of the total value of bitcoin (of course, you can't refute me technically, just for a rough explanation). Once we add up all the branches of bitcoin, we can calculate the market value of more than $310 billion. As a result, bitcoin accounts for about 60% of all cryptocurrencies in the market

as I have repeatedly said in recent days, bitcoin is not the most effective cryptocurrency, the most advanced, the most anonymous, or even the most stable cryptocurrency. So why is bitcoin so valuable compared with other virtual currencies

it's very simple, because bitcoin has a catalytic factor, that is, the Chicago Board of trade, as well as the commodity exchange, began to trade futures as a "commodity". Then, you will naturally think that since it has been recognized by the futures exchange, will it be further recognized by the US government in the next step. Other virtual currencies are still struggling

however, we have always stressed that since the day bitcoin was traded as a "commodity", its real monetary role, like gold, has been very weak in reality, but as one of the procts of gambling. This means that we all do bitcoin as a speculative activity, rather than a real use

judging from the current situation, bitcoin is no longer the only virtual currency that soars as soon as there is news of "official support". It is like iota, a virtual currency that focuses on the principle of the Internet of things. The news of cooperation with Microsoft came in the last two weeks, and it immediately rose to more than $300. Later, Microsoft came out and said that there was no such thing, and iota immediately fell back. It can be seen that in the future, as long as the virtual currency is recognized by some big company or organization, it will soar like bitcoin