H bitcoin Wallet
bitcoin is a kind of e-cash similar to e-mail. Both parties need "bitcoin wallet" similar to e-mail and "bitcoin address" similar to e-mail address
just like sending and receiving e-mail, the remitter will pay bitcoin directly to the other party according to the recipient's address through the computer or smart phone. The following table lists some websites that download bitcoin wallets and addresses for free
a bitcoin address is a string of letters and numbers about 33 bits long, always starting with 1 or 3, such as ""
bitcoin software can generate address automatically, and it does not need to exchange information online when generating address, so it can be offline. More than 2 bitcoin addresses are available
figuratively speaking, there are about two grains of sand in the world. If there is an earth in each grain of sand, then the total number of bitcoin addresses far exceeds the number of all the sand on all these "earths"
extended materials:
bitcoin is introced as follows:
bitcoin has its own technical advantages in blockchain digital currency. Bitcoin has four main characteristics: no centralized issuer, limited total amount, no geographical restrictions and anonymity. Although bitcoin is called "currency", because it is not issued by the monetary authority, it does not have the monetary attributes of legal compensation and mandatory
is not a real currency. In nature, bitcoin should be a specific virtual commodity, which does not have the same legal status as currency, and can not and should not be used as currency in the market
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.
experience
the world's first bitcoin ATM was set up in Vancouver Cafe
"the world's first" bitcoin ATM was opened in Vancouver, Canada, on the 29th, to exchange Canadian dollars and bitcoin, quickly ushering in people queuing for business. The ATM is made by American machine money and is located in a cafe called trendy in Vancouver. One of the ATM owners is Mitchell Demeter, who has been trading bitcoin for several years. This year, he partnered with two other high school classmates to set up a bitcoin trading company. Demeter said it was the world's first bitcoin ATM. Demeter and his colleagues think that bitcoin ATM is a business opportunity, because before "there was no bitcoin ATM, we all trade on the website"
ring the operation, the bitcoin user enters a password similar to the bank pin code to log in to the network bitcoin account. Through the ATM, the user can withdraw the Canadian dollar cash corresponding to the ratio from the bitcoin account, or deposit the cash into the bitcoin account. Bitcoin users only need a smart phone to use bitcoin, which is similar to online shopping
easy access
15 instries in Vancouver accept bitcoin
businessman David loy used his mobile phone to transfer 0.0101 bitcoin to "trendy" cafe and bought a cup of black coffee worth 2 Canadian dollars. Roy believes that Vancouver has a large number of online businesses, creating conditions for setting up the first bitcoin ATM. Mike young, a business student at Simon Fraser University in Canada, also came to the bitcoin ATM on the 29th. He and others founded a bitcoin club on campus, believing that bitcoin "is the trend because they can provide maximum value and efficiency"
a man with an alias of Nakamoto created bitcoin in 2008. Since then, the virtual currency has graally become popular on the Internet. About 15 instries in Vancouver have accepted bitcoin, including coffee shops and landscape design companies. Bitcoin can rece the cost of capital transfer in countries with weak banking systems, a senior investment executive at Fort investment group commented this month, the Financial Times reported
Transaction mode of bitcoin
bitcoin is e-cash similar to e-mail, and both parties need "bitcoin wallet" similar to e-mail and "bitcoin address" similar to e-mail address. Just like sending and receiving e-mail, the remitter pays bitcoin directly to the other party through a computer or smart phone according to the recipient's address. The following table lists some websites that download bitcoin wallets and addresses for free
a bitcoin address is a string of about 33 characters long, consisting of letters and numbers, always starting with 1 or 3, such as & quot& quot; Bitcoin software can generate address automatically, and it doesn't need to exchange information online, so it can be offline. More than 2 bitcoin addresses are available. Figuratively speaking, there are about two grains of sand in the world. If there is an earth in each grain of sand, then the total number of bitcoin addresses far exceeds the number of all the sand on all these "earths"
the bitcoin address and private key appear in pairs, and their relationship is just like the bank card number and password. A bitcoin address is like a bank card number, which records how much bitcoin you have on it. You can generate bitcoin address at will to store bitcoin. When each bitcoin address is generated, a corresponding private key of the address will be generated. This private key proves that you have ownership of the bitcoin at that address. We can simply understand the bitcoin address as the bank card number, and the private key of the address as the password of the corresponding bank card number. Only when you know the bank password can you use the money on the bank card number. Therefore, please keep your address and private key when using bitcoin wallet
after the transaction data of bitcoin is packaged into a "data block" or "block", the transaction is initially confirmed. When a block is linked to a previous block, the transaction is further confirmed. After six block confirmations in a row, the transaction was irreversibly confirmed. Bitcoin P2P stores all transaction history in a "blockchain.". The blockchain continues to extend, and once new blocks are added to the blockchain, they will not be removed. Blockchain is actually a distributed database composed of a group of scattered client nodes and all participants, which is a record of all bitcoin transaction history. Nakamoto predicts that when the amount of data increases, users hope that not all the data will be stored in their own nodes. In order to achieve this goal, he uses the hash function mechanism. In this way, the client will be able to automatically eliminate those parts that it will never use, such as some very early bitcoin transactions
the birth of bitcoin
the birth of bitcoin should be on November 1, 2008. A man with the pseudonym of "Nakamoto Tsung" published a paper on the Internet. In this paper, he described in detail a new monetary system, which he named "bitcoin"
then, on January 3 of the next year, the first bitcoin program was born in the hands of Nakamoto Tsung, along with the first 50 bitcoins from mining. After that, he began to fade out until he disappeared completely
so far, people have not found out the real identity of this person, even if today's operators, Internet giants and the government have firmly grasped people's behavior on the Internet
he often switches between American and British English when he speaks. He goes online at different times of the day at random to hide his nationality and time zone; He hides his IP address, encrypts his email, and deliberately forges some writing and speaking styles to confuse the public; Besides, he is also an expert in cryptography. By the way, the place where he published his paper is called & quot; Cryptography mailing list & quot
so bitcoin was born with a hacker spirit: against the censorship imposed by any force
of course, we can also see that if a hacker who invented the anonymous currency system can't be anonymous, the whole thing will become a joke< But fortunately, Nakamoto didn't let us down
1. What is currency
I find that I can't run this section in any case to clarify what is bitcoin. I am not an expert in the field of economics. I can only talk about this issue in a very superficial and intuitive sense However, as far as the theme expressed in the title is concerned, it seems to be enough)
it has been mentioned in senior high school textbooks (remember?), Money is the medium to store value. If a thing wants to become money, it must meet the following requirements:
1) scarcity
that's why gold can be used and sand can't be used as money. Scarcity can be understood as the difficulty of obtaining it. The more scarce it is, the more difficult it is to obtain it. An intuitive understanding is as follows: assuming that your monthly salary is 5000 yuan, it means that the scarcity of RMB is just such a degree, that is, you have to pay a month's labor to get 5000 yuan. You won't agree to pay your salary with 5000 grains of sand, because instead of working for a month to get it, you can easily get it by walking around the beach
how does the current financial system guarantee the scarcity of money? Control distribution. The issue of money is firmly in the hands of the central bank, so that the amount of money can be controlled (so you now know that it is illegal to print money without permission). Back to the example just now, you agree to pay you a month's salary with 5000 yuan because the circulation of RMB has just reached this level. If the circulation of RMB doubles and the scarcity decreases, you should ask for 10000 yuan to pay your salary (but the response of the market is often not so fast. During this period, your wealth is actually deprived - your labor should have received 10000 yuan, but only 5000 yuan in return)
2) transactional
of course, the purpose of currency is to trade. As many people tell you, money is spent, not brought into the coffin. So in addition to meeting scarcity, the more convenient it is for a thing to trade, the more it meets the standard of ideal currency. Therefore, in the history of currency, silver dollar has replaced shells, paper money has replaced silver dollar, and digital currency is graally replacing paper money
the "transaction" here refers to the transfer of property from one party to the other, that is, the decrease of one party's property and the corresponding increase of the other party. For physical currency, it happens very naturally. A wants to give 100 yuan to B. when the 100 yuan note is transferred from a's hand to B's hand, the transaction is completed. A's property is reced by 100 yuan and B's property is increased by 100 yuan. There is no third party involved in this process, which is completely a private act between a and B; However, when the transaction takes place at the level of digital currency, it is not so simple. Party A has to give 100 yuan to Party B. how can we ensure that the transaction is completed? Suppose that a and B record their wealth on their respective computers, how can we ensure that when B adds 100 yuan to them, a actually subtracts 100 yuan from them? Now we have to bring in a third party - the guy we call the bank. When a wants to transfer 100 yuan to B, he doesn't directly give it to B, but to the bank, "please transfer my 100 yuan to B", so the bank dected 100 yuan from a's account and added 100 yuan to B's account Let's assume that it generously does not charge any transaction fee)
the above is a rough model of modern monetary system. The biggest disadvantage of this model is that people have to trust a central system
the transaction of digital currency must rely on the bank, and a person's bank account number may be censored, restricted or even deprived. When one party wants to transfer his wealth to the other party, the bank can charge a high fee or refuse directly (for example, you try to remit a sum of money to a relative in the United States)
the issuance of money must rely on the central bank. Well, it's a well-known secret: the currency has been devaluing, or over issuing (think of the $100 20 years ago and the $100 now). I quote two paragraphs, one of which is Keynes's saying, "through a continuous process of inflation, the government can confiscate a part of citizens' wealth secretly and unknowingly. In this way, we can deprive the people of their wealth at will, while making the majority poor, we can make the minority rich, Another paragraph, from Hayek, "the government can not restrain the impulse to issue money indiscriminately."
is it possible to design a monetary system in which we do not need a central institution and are not forced to trust any third party, so as to make the issuance of currency transparent and controllable, and the transaction of currency private and secure
guess what
2. What is bitcoin
so we can now answer that bitcoin is an e-money system with decentralized distribution and transaction. In this system, the circulation of money is transparent and predictable, and the transaction of money uses the cooperation of the whole network to ensure the security of the transaction
next, I will graally dismantle the principle of bitcoin. It should be noted that bitcoin, as a proct already in use, has a lot of details. The purpose of this article is to explain the basic principles of bitcoin to readers without technical background, so these details will not be covered. For example, the address of the wallet is not the public key, but the second hash value of the public key; The difficulty requirement of blockchain is not to hash all the contents of blockchain once; wait. But for the sake of brevity, without affecting the explanation of the basic principles, these are simplified. I hope you can understand them
2.0. Bitcoin network is composed of many nodes running bitcoin programs
bitcoin is a network composed of many equal nodes
a node is a bitcoin program. Any machine that can connect to the Internet and have certain computing power can run this program - so your home computer can also be used as a node in the bitcoin network:)
nodes can communicate with each other. At the same time, bitcoin has a set of mechanism that allows a node to send messages to all other nodes, This behavior is called "broadcasting."
2.1. Blockchain - a public account book
let's go back to the example of banks. The most basic function of a bank is to maintain an account book, which only needs to record every transaction truthfully. For example, Wang Xiaoming transferred 30 yuan to Zhang Damao on X, year X; On y, y, y, y, Zhang Da Mao transferred 12 yuan to Li Xiao Dou, and so on. According to this account book, we can find all the transaction records of a person, so we can calculate the current account balance of the person. For example, since Li Xiaodou started to build a bank account, the total amount of transactions transferred in is 500 yuan, and the total amount of transactions transferred out is 300 yuan. Then it can be calculated that the balance of Li Xiaodou's account must be 200 yuan at this time
maintain this account book, and as the only maintainer (only the bank has the right to view and modify), the bank's responsibility as a trading center is completed
bitcoin also has an account book, but unlike banks, this account book is open and anyone can view and review it
this account book is called & quot; Blockchain & quot;. You can think of blockchain as a pamphlet. Every page of the pamphlet is full of transaction information, and new pages are constantly added<
2.2 Wallet - an account composed of a pair of public keys and private keys
the above section explains what a bitcoin account book is. This section will explain the ownership of funds in this account book, that is, the account system of bitcoin
there are essential differences between accounts in bitcoin and bank accounts
under a bank account, the bank records the identity information of the owner of the account (think back to the information you submitted when you went to the bank to open an account: photo, ID card, telephone number, home address...), so as long as you can prove your identity to the bank, you will get the ownership of the property under your name. In this model, the bank plays the role of an omniscient God: he knows the wealth information of real people. We have no choice but to pray to God not to let our information out or use it for evil
in the world of bitcoin, there is no such institution as bank, which will not force people to reveal their identities in exchange for the security of funds. Bitcoin's account is simply composed of two strings of numbers, which are called "public key" and "private key" respectively, and there is nothing else
the mathematical characteristics of these two numbers - a data encrypted by a private key can only be decrypted by a public key, so-called asymmetric encryption - enable them to perfectly implement the functions required by an account (called a wallet in the bitcoin world)
we take the public key as the account address - also known as the wallet address in the bitcoin world - which is similar to the account number in the banking system, that is, when you tell someone "please call 300 yuan for my account number", you need to tell them. For the bank, it is "China Merchants Bank 6214850200251100", compared with the special currency, it is "
the private key is the * only * certificate to prove the ownership of the wallet. You can hold it by proving that you are the private key of the wallet
through the ATM, users can withdraw the Canadian dollar cash corresponding to the ratio from the bitcoin account, or deposit the cash into the bitcoin account
bitcoin users only need a smart phone to use bitcoin, which is similar to online shopping. A bitcoin address is about 33 characters long, a string of letters and numbers, always starting with 1 or 3, such as & quot& quot; Bitcoin software can generate address automatically, and it does not need to exchange information online when generating address, so it can be offline [2]. More than 2 bitcoin addresses are available. Figuratively speaking, there are about two grains of sand in the world. If there is an earth in each grain of sand, then the total number of bitcoin addresses far exceeds the number of all the sand on all these "earths"
bitcoin address and private key appear in pairs, and their relationship is like bank card number and password. A bitcoin address is like a bank card number, which records how much bitcoin you have on it. You can generate bitcoin address at will to store bitcoin. When each bitcoin address is generated, a corresponding private key of the address will be generated. This private key proves that you have ownership of the bitcoin at that address. We can simply understand the bitcoin address as the bank card number, and the private key of the address as the password of the corresponding bank card number. Only when you know the bank password can you use the money on the bank card number. Therefore, please keep your address and private key when using bitcoin wallet.
bitcoin (bitcoin: bitcoin):
was originally a kind of network virtual currency, which can buy real-life goods. It is characterized by decentralization, anonymity, and can only be used in the digital world. It does not belong to any country or financial institution, and is not subject to geographical restrictions. It can be exchanged anywhere in the world. Therefore, it is used as a money laundering tool by some criminals. In 2013, the U.S. government recognized the legal status of bitcoin, making the price of bitcoin soar. In China, on November 19, 2013, a bitcoin was equivalent to 6989 yuan
< UL > transaction mode:
bitcoin is e-cash similar to e-mail, and both parties need "bitcoin wallet" similar to e-mail and "bitcoin address" similar to e-mail address. Just like sending and receiving e-mail, the remitter pays bitcoin directly to the other party through a computer or smart phone according to the recipient's address. The following table lists some websites that download bitcoin wallets and addresses for free
a bitcoin address is a string of about 33 characters long, consisting of letters and numbers, always starting with 1 or 3, such as & quot& quot; Bitcoin software can generate address automatically, and it does not need to exchange information online when generating address, so it can be offline [2]. More than 2 bitcoin addresses are available. Figuratively speaking, there are about two grains of sand in the world. If there is an earth in each grain of sand, then the total number of bitcoin addresses far exceeds the number of all the sand on all these "earths"
the bitcoin address and private key appear in pairs, and their relationship is just like the bank card number and password. A bitcoin address is like a bank card number, which records how much bitcoin you have on it. You can generate bitcoin address at will to store bitcoin. When each bitcoin address is generated, a corresponding private key of the address will be generated. This private key proves that you have ownership of the bitcoin at that address. We can simply understand the bitcoin address as the bank card number, and the private key of the address as the password of the corresponding bank card number. Only when you know the bank password can you use the money on the bank card number. Therefore, please keep your address and private key when using bitcoin wallet