The metaphor of blockchain ledger
for example, if you are a woman, every time your boyfriend says something disgusting to you or promises to buy something for you, you immediately record it and send it to you and all his friends, classmates, colleagues, as well as various groups and circles of friends, so that he can no longer resist. This is called blockchain
the core advantage of blockchain technology is decentralization, which can realize point-to-point transaction, coordination and cooperation based on decentralized credit in a distributed system without mutual trust by means of data encryption, time stamp, distributed consensus and economic incentive, so as to solve the high cost and low cost of centralized institutions Low efficiency and data storage insecurity provide solutions
the application fields of blockchain include digital currency, token, finance, anti-counterfeiting traceability, privacy protection, supply chain, entertainment, etc. with the popularity of blockchain and bitcoin, many related top domain names have been registered, which has a great impact on the domain name instry.
"Blockchain is equivalent to this account book, and the block is equivalent to a page of this account book. The information carried in the block is the transaction content recorded on this page. The blockchain is block by block, and each block is filled with transaction records and connected together to form a chain, which is called blockchain. "
take bitcoin as an example, there is a "power race" every ten minutes to compete for the right to charge. It's like saying that you have a lot of calculation power, just like your muscles are stronger and more capable of fighting. Everyone will convince you to keep this account, that is, the right to write a block (note that it is not the content in the block) to the general ledger of the blockchain. However, it should be noted that computing power can only determine the probability of winning the competition. For example, there are several lotteries in total, and those with more computing power can buy more to improve the winning probability. However, those who buy more may not win the lottery in the end.
blockchain is a data block chain guaranteed by such computing power. Starting from the first block, each block collects data according to certain rules, and then attaches a value to these data, so that the result of the formed data block after similar one-way function calculation falls into a certain range. By estimating the computing power of the whole network and the size of the control result range, the data blocks that meet the requirements can be found in a long enough time. This calculation result will be included by the next block, and the chain data structure formed in this way is called blockchain
each small ledger is called a block, and each different blockchain protocol (generating different cryptocurrency) will specify the size of each block (the initial bitcoin is 1m). The ledger constitutes a block, the block constitutes a chain list, and the block header contains the hash value of the previous block, which is the blockchain. In this way, no one can modify the content or exchange the order at will. If you do, it means you need to recalculate all the special numbers
regulations allow everyone in the world to build blocks. Every person who builds a new block (finds this special number - sha256 value has 30 zeros) can get a reward. For this part of people (miners) who build a new block:
1. There is no sender information, There is no need to sign
2. Each new block will add a new virtual (encrypted) currency to the whole currency
3. The process of building a new block is also called "mining": it requires a lot of work and can inject new currency into the whole economy
4. The work of mining is: receiving transaction information, building blocks, broadcasting blocks, Then get new money as a reward
for each miner, each block is like a small lottery, and everyone is trying to guess the number quickly until a lucky person finds a special number, so that there are many zeros at the beginning of the hash value of the whole block, and they can get a reward. I remember a Zhihu respondent gave an image analogy. Blockchain is like a king with a beautiful daughter (block). Many young people are looking forward to it. The king's method is to give a very difficult topic for all young people to calculate (learning to change their lives), Who can calculate quickly (or be lucky in the process of calculating the hash value) will be able to win the beauty
for users who want to use this system to collect and pay, they don't need to listen to all the transactions, but just listen to the blocks broadcast by the miners, and then update them to their saved blockchain
"block" can also be imagined as a box, There are some digital currencies and a small note in the block, on which the only transaction information generated in the past ten minutes is recorded, such as "small a transferred to small B100 yuan"; Of course, this piece of information must have been encrypted to ensure that only small a and small B (through the key in their hands) have the ability to interpret the real content
after this magical block was created, it was soon buried underground. Where is it buried? No one does not know that all computer nodes need to participate in digging three feet before it is possible to find (find an effective workload proof). Obviously, this is an event with huge workload and random results. However, for the computer node, once the block is g out from the ground, it will get the valuable digital currency in the block, as well as the tip paid by small a in the process of "small a transferred to small B100 yuan". At the same time, for this node, only he has the right to truly record the contents of the note, which is an honor, while other nodes can only use its , a without digital currency blessing. Of course, there are some other special things about this magical block.
the process of computer nodes digging out blocks from underground is called "mining". As I said just now, this is a huge workload, a lot of luck and a lot of profits. A node on zhangheng road in Pudong New Area of Shanghai, China, suddenly jumped out and said excitedly, "I've g the block! The little notes inside are all valid! The reward belongs to me! ". Although Zhang Heng Road node has got digital currency at the moment, for other computer nodes, because it also involves some other interests, they will not choose to believe what Zhang Heng Road node says by default; Based on the principle that strangers do not trust each other, they take the so-called block () g by Zhang Heng Road node, and start to check whether the small note information in the block is true and effective, etc. In the world of blockchain, nodes check the accuracy of the small note information, or indirectly or directly judge whether the node that successfully digs out the block is lying How to define the true and effective information of a small note will be explained later, but I won't go into details here. In the verification process, each node will directly express their identification (accurate) and attitude towards zhangheng road node through the following two behaviors: stop half or even 80% of the mining process; Add the block () g out by zhangheng road node to the end of its own blockchain. You can be a little confused: if you stop mining, you may have done 80% of the mining work. Then 80% of the previous work is in vain?! Then, what the hell is at the end of the blockchain? For the first puzzle. I want to say that what you said is right, but there is no way. The reality is so cruel. Even if 80% of the work is done, you have to give up. The 80% of the work can be regarded as useless, absolutely damaging the wealth and the masses. The second puzzle is, what is the ghost at the end of blockchain and blockchain? Here, it is not clear in advance, but you can simply imagine: blocks are generated and g out periodically, and a computer node may have executed "take blocks from others" n times in advance; The process of "checking the validity of small notes" must have stored n blocks on its own node, and these blocks will be arranged in a chain in order of time. Yes, this chain is what you always think of as the blockchain. If you still can't understand, it doesn't matter. There will be many opportunities for in-depth study later in the article
go into the more microcosmic world of the block and have a look at what the little note really is, how it came into being and its mission all its life: when initiating a transaction, the initiator will receive a little note, and he needs to write the transaction record, such as "stealing transfer to a piece of RMB 340" on the paper. It's amazing that when it's finished, on the back of the note, the transaction record will be automatically formatted to at least contain the two important fields of "input value" and "output value"“ Input value is used to record the effective source of digital currency, and output value is used to record the object to which digital currency is sent. The newly created note is immediately marked as an "unconfirmed" note. Small pieces of paper that are successfully g out of the ground and eventually connected to the blockchain are initially marked as "valid.". If the valid slip is used as the input value of other transactions, the valid slip will soon be marked as invalid. Due to various reasons, the block is disconnected and discarded from the chain, and the small notes once marked as "valid" in the block will be re marked as "unconfirmed". There is no concept of account balance in the blockchain. The digital asset you really own is actually a piece of transaction information; Get the balance in your digital wallet by simple addition and subtraction. The above 1, 2 and 3 are just the knowledge points forced to you at the beginning. Some of the descriptions may be a bit confusing, which makes you feel confused. Only by understanding the whole blockchain can you have a more comprehensive understanding of the mystery
block capacity. Bitcoin specifies that the block capacity is 1m when it is created, or in the source code. The reason why it was originally designed as 1m is, on the one hand, to prevent DoS attacks. On the other hand, when Zhongben Cong created the blockchain, the capacity was 32m. However, he changed the block capacity to 1m through a humble commit like "clear up". In order to prevent the volume of the blockchain from growing too fast, he added some mystery to the problem of block capacity. The capacity of 1m means that the maximum number of transactions processed by bitcoin is about 2400 (the size of 486882 block 1034.39 is very close)
to put it bluntly, blockchain is a small book for distributed bookkeeping, a tool for bookkeeping, and based on cryptography and cryptography technology, once data transactions are recorded in the book of blockchain, data can not be tampered with and denied. The Internet is the transmission of value, and the blockchain is the transmission of trust. Under the premise of blockchain technology as a credit endorsement, each node in the blockchain changes from a single center to a unified multi center with multi-party participation, which can achieve transaction transmission without the participation of a third party organization and improve the efficiency
1. What the Internet changes is the acquisition and transmission of information, while what blockchain does is the transmission of value
for example, on the Internet, we can easily and quickly generate information and it to any place. All information can be spread efficiently, but some valuable information that can only be transferred but cannot be shared often needs credit endorsement
for example, we can't the payment directly to the other party, but we need to subtract some money from the payment account and add some money to the collection account to complete the payment process. The current Internet protocol does not support the function of value transfer. The current value transfer is not direct transmission. Instead, it is endorsed by a centralized third party, such as Alipay, such as banks.
now these centralized organizations put all the calculation of value transfer in a centralized server, which will certainly involve the participation of people, which will cause many problems, such as some "finite theory" and "opportunistic behavior", which will make the whole behavior less credible. So there is a basic question, how to reach a credit consensus
this is how blockchain technology came into being. It can be said that blockchain can build a pure point-to-point value transfer system. Without the mutual trust of each node, blockchain can ensure the integrity and security of data records in the system, and can be separated from the endorsement of third-party organizations, effectively recing the complexity and risk of transactions
2. It is open and transparent, and can not be tampered with
all data of the blockchain can not be tampered with or deleted, and the information of the whole system is open and transparent. If someone owes you a sum of money, and now the data has been put on the blockchain, if he doesn't want to return it to you and play a rogue with you, you can go to the court to protect your rights through the data forensics on the blockchain, so as to get back your legitimate funds. Because the data on the blockchain is open to the whole network, the users of the whole network will know his rogue behavior, which will greatly increase his credit cost. Dishonesty will make him have an important impact in the next life.
Ledger is a book with a certain format and several account pages. Based on the accounting documents, it records all economic business in chronological order and classification, which is what we usually call the ledger. Blockchain represents a unique data record format. Blockchain is "block + Chain". The so-called block is the meaning of data block. Each block is connected by a certain mark to form a chain
Super ledger
hyperledger (Chinese name is super ledger, collectively referred to as hyperledger) is an open source project launched by Linux foundation in 2015 to promote blockchain digital technology and transaction verification. The goal of hyperledger is to enable members to work together to build an open platform to meet the needs of various users from different instries, while greatly simplifying the business process. The founding members of hyperedge include IBM, Intel, Cisco and other large companies. By the end of this book, more than 183 organizations and companies have joined hyperedge, and they are growing rapidly
at the beginning of hyperledger project, Linux foundation has received a number of different code bases, including IBM code base (inspired by Ethereum to a certain extent), Dah (bits of proof bitcoin code base) and sockstream code base (an extension of bitcoin code base). In addition, there are digital asset and ripple contributions. With the development of the instry, a single project has been unable to meet the needs of the business, so hyperledger has graally developed from a single project into a project group. At present, hyperledger is not a specific technology, but a set of blockchain technology frameworks. Up to now, the hyperledger project team contains 9 formal projects and more than 50 moles related to these formal projects
the Xueshuo innovation blockchain Technology Workstation of Lianqiao ecation online is the only approved "blockchain Technology Specialty" pilot workstation of "smart learning workshop 2020 Xueshuo innovation workstation" launched by the school planning, construction and development center of the Ministry of ecation of China. Based on providing diversified growth paths for students, the professional station promotes the reform of the training mode of the combination of professional degree research, proction, learning and research, and constructs the applied and compound talent training system