Blockchain Zhu Xiaohu

1.

If you want to understand the application of blockchain, you can refer to many books and opinions, such as illustrated blockchain, blockchain: reshaping the economy and the world, blueprint and guide of new economy, and articles of coin'an community, including a detailed understanding of the platform of coin'an community, with great strength

As the name suggests, blockchain is composed of block and chain. It is a new application mode of computer technology such as distributed data storage, point-to-point transmission, consensus mechanism, encryption algorithm and so on. It is a kind of chain data structure that combines data blocks in order according to the time sequence, and it is a secure and reliable distributed account book that can not be tampered with and forged by means of cryptography

in 2008, in his paper bitcoin: a peer-to-peer e-cash system published by Nakamoto, he first proposed the idea of blockchain and encrypted digital currency. Starting from bitcoin, blockchain has become the underlying technology of various digital currencies

Second, the working principle of blockchain:

1. The basic concepts include: (1) transaction: one operation will change the account status once, such as adding a record 2) Block: records the transaction and status data within a specified time, which is a consensus and preservation of the current account status 3) Chain: it is composed of a series of blocks in chronological order, which is the log record of the whole state change. If you understand the working concept of blockchain, it is not difficult to understand its working principle. Suppose there is a distributed data logbook, which can only be added, not deleted or changed. Its structure is a linear chain formed by a series of "blocks" (which is also the source of the name of "blockchain"), and new data must be put into a new block to be added, The maintenance node can propose a new block, but it must go through a certain consensus mechanism to reach an agreement on the final selected block

2. Take bitcoin as an example to see the working principle of blockchain

the block of bitcoin is divided into block head and block body

Core advantages and characteristics of blockchain

1. The verification, accounting, storage, maintenance and transmission of decentralized blockchain data are all based on distributed system structure. There is no centralized hardware or management organization, and the rights and obligations of any node are equal, The data blocks in the system are jointly maintained by the nodes with maintenance function in the whole system. 2. The open and transparent system is open. In addition to the private information of all parties to the transaction is encrypted, the data of the blockchain is open to all. Anyone can query the blockchain data and develop related applications through the open interface, so the information of the whole system is highly transparent. 3. Security blockchain uses consensus based specifications and Protocols (such as a set of open and transparent algorithms) to enable all nodes in the whole system to exchange data freely and safely in a de trusted environment, so that the trust in "people" is changed into the trust in machines, and any human intervention does not work. 4. Information cannot be tampered with. Once the information is verified and added to the blockchain, it will be stored permanently. Unless more than 51% (almost impossible) nodes in the system can be controlled at the same time, the modification of the database on a single node is invalid. Therefore, the data stability and reliability of the blockchain are extremely high. 5. Anonymity because the exchange between nodes follows a fixed algorithm, and its data interaction does not need trust (the program rules in the blockchain will judge whether the activity is effective or not). Therefore, the counterparties do not need to let the counterparties generate their own trust by disclosing their identities, which is very helpful for credit accumulation

At present, the most popular classification of blockchain is to divide blockchain into public blockchain, private blockchain and consortium blockchain according to different participants

1. Public chain: anyone can participate in the use and maintenance, and can obtain the effective confirmation of the blockchain. Public chain is the earliest blockchain and the most widely used blockchain at present, such as bitcoin blockchain. The information is completely public

if the licensing mechanism is introced, it includes private chain and alliance chain. 2. Private chain: a company or indivial only uses the blockchain technology, enjoys the exclusive write permission of the blockchain, and does not disclose the information. At present, conservative giants (traditional finance) want to experiment with private blockchain, and the application procts of private blockchain are still groping. 3. Alliance chain: it is a blockchain between the public chain and the existing chain, which is jointly controlled by multiple organizations. The use of the chain is managed with authority, which can be controlled by the manager, and also open to others according to the manager's wishes. In addition, according to the different use scenarios and purposes of blockchain, it can be divided into currency chain for the purpose of digital currency, property chain for the purpose of recording property rights, and crowdfunding chain for the purpose of crowdfunding

On May 28, Ma Huateng, CEO of Tencent, proposed the anti-counterfeiting method based on cloud integrated blockchain technology, which is far more efficient than traditional anti-counterfeiting methods. The future anti-counterfeiting verification scenario may only require users to use their mobile phones for simple scanning, and a large number of complete information based on different dimensions can be obtained

take Maotai liquor as an example:

distillery address, proction workshop, operation staff, inspector, delivery time, transportation vehicle information and driver information,

liquor year, raw material source, raw material supplier, storage warehouse number, raw material transportation vehicle and driver information,

all information can be accurately traced, permanently recorded and tampered with

the above information can be easily verified

2. Food safety issues as early as last November, Wal Mart has cooperated with IBM to track the source of food by using blockchain technology, so as to ensure the safety of food and increase the circulation of food to rece costs. For Wal Mart and other large supermarkets, it took a few days to investigate the source of problem food, After using this technology, only one item of proct information is needed to achieve accurate traceability, and important information such as food origin, inspector, supplier, logistics and transportation can quickly find problems in a few minutes. Currently, procts tracked by blockchain include packaging procts from the United States and pork from China

3. Information security

blockchain technology is promoting an information security technology revolution. (1) identity protection PKI is a common public key encryption technology in e-mail, message application, website and other communication applications. However, since the implementation of most PKI, the centralized trusted third party certification authority (CA) is used to issue, activate and store user certificates. Hackers can attack PKI to fake user identity or crack encrypted information

certcoin is the first PKI implementation of blockchain, which comes from MIT, removes the centralized authentication center, and uses blockchain as a distributed ledger for domain name and public key

pomcor company: blockchain PKI implementation path: keep the authentication center, and use blockchain to store the hash value of issued and activated certificates. Users can verify the authenticity of certificates through decentralized and transparent sources, and can also improve the network access performance through local authentication of secret key and signature based on blockchain

(2) data integrity protection

guardtime developed a secret key free signature architecture (Ksi) based on blockchain technology to replace the secret key based data authentication technology. Ksi stores the hash table of the original data and files on the blockchain, runs the hash algorithm to verify other copies, and compares the results with the data stored in the blockchain. Any data tampering will be found quickly because the original hash table is stored in millions of nodes

(3) key infrastructure protection

the "Achilles heel" of the Internet, DDoS has entered the TB era, DDoS is still the simplest weapon for hackers to bring down the big target with low cost, DNS service is the primary target for hackers to carry out large-scale destruction, but blockchain technology is expected to fundamentally solve the problem

The distributed storage of

blockchain makes hacker attacks lose focus. Nebulis is developing a distributed DNS system, which uses Ethereum blockchain and interstellar Internet file system (IPFs, the distributed substitute of HTTP) to register and resolve domain names. The biggest weakness of DNS is caching, which makes DDoS attacks possible. It is also the bane of the centralized government's censorship of social networks and manipulation of DNS registration. A highly transparent and distributed DNS system can effectively prevent any entity, including the government, from arbitrarily manipulating records

(1) digital currency: improve the convenience of currency issuance and use, such as bitcoin and Ethernet in foreign countries, and guorenbao in China

from the use of physical transactions, to physical currency and credit currency, and then to the rise of bitcoin network, more and more people are aware of the distributed ledger blockchain technology behind it, and graally apply it in many scenarios other than digital currency

(2) cross border payment and settlement: realize point-to-point transaction, rece intermediate fees

transfer and payment. At present, the most mature application of blockchain technology is payment and transfer. Blockchain technology can avoid complicated systems, save the process of inter-bank reconciliation and review, and accelerate the settlement speed; virtual currency can rece transaction costs without the intervention of clearing house. Different countries have different clearing proceres. It takes two or three days for a single remittance to arrive, which is inefficient and accounts for a large proportion of funds in transit. No longer through the third party, through the blockchain technology to form point-to-point payment. By eliminating the link of the third-party institutions, we can make full day payment, real-time payment, withdraw cash quickly and rece the hidden cost, which helps to avoid the capital risk. It is timely and convenient

(3) bills and supply chain financial business: rece human intervention, rece costs and operational risks

value transfer between point-to-point, control and verify physical bills or central system; Intermediaries will be eliminated and human intervention reced. With the improvement of efficiency, financing channels are more unblocked, risks are lower, and multiple parties benefit

(4) securities issuance and Trading: realize quasi real-time asset transfer, accelerate the speed of transaction clearing

the application of blockchain technology can make the process of securities trading more concise, transparent and fast, rece the plication of IT system, and improve the efficiency of market operation. For stocks, blockchain can eliminate paper and pen or electronic form records, rece human errors in trading, and improve the transparency and traceability of trading platform. Citigroup and Nasdaq cooperate to promote blockchain applications

(5) customer credit investigation and anti fraud: rece the cost of legal compliance, prevent financial crimes

the customer information and transaction records recorded in the blockchain help banks identify abnormal transactions and effectively prevent fraud. The technical characteristics of blockchain can change the existing credit reference system, and store the data of customers with bad records in the blockchain when the bank concts "know your customer" (KYC)

equity crowdfunding:

2.

A vigorous "blockchain movement" is sweeping like a wave, threatening everyone around. From last year to this year, the debate over blockchain has never stopped. Is blockchain, as its advocate Chen Weixing said, the "spring of mankind", the "antidote to the global economic collapse", or as his doubter Zhu Xiaohu said, "blockchain is a fake outlet, and there is nothing left except currency speculation"

we think that this instry needs standards, otherwise we will talk about blockchain for a long time, and the concept of talking is not the same, and even some enterprises claim to make their own blockchain, and they just change the database. With the authoritative standard of trusted blockchain, we can screen out the enterprises that obviously sell dog meat, and let the enterprises that really do blockchain technology get endorsement

Ce: how does Tencent solve the problem of talent scarcity in the blockchain field

CAI Yige: our technical talents are basically transformed from Tencent. The blockchain instry is very new, and few people have done blockchain. Just like the arrival of mobile network in those years, it's very difficult for you to recruit Android and IOS developers. We all cultivate ourselves

3.

By midday, bitcoin had fallen to around $10700. Bitcoin's previous attempt to break through $12000 failed, and yesterday's downward trend continues to this day. As a result, the cryptocurrency market fell, with 90 of the top 100 currencies falling

in the past 24 hours, according to the okex platform, the net outflow amount of bitcoin reached 638 million yuan, and according to the currency security data, the net outflow amount of bitcoin reached 152 million yuan. Although the capital outflow in the past 24 hours is relatively large, it has decreased compared with yesterday's capital outflow, and bitcoin has hit the bottom of US $10600 for many times in the past 24 hours. However, in terms of trading volume, there is strong support in this position. After that, we still need to observe the withdrawal of funds, so as to confirm whether the market goes up or continues to fall below the down. In fact, the so-called "bear market" in the currency circle is more popular than the "three o'clock community" before. In my opinion, I basically dare to assert that there are makers in the currency circle who have successfully harvested a batch of "leeks" by using some financial means or big men. This view may sound like "conspiracy theory" to many people, But I have to admit that speculators are everywhere in the coin circle. Zhu Xiaohu's warning that "I hope you don't stay in history because you reap leeks to earn money with blood" also has a certain basis in my opinion

the craziest time was in December 2017, when bitcoin reached more than 100000 yuan. Before that, people who invested in bitcoin could make a fortune overnight. At the end of 2017, the price dropped to below 40000 yuan, and there was also a correction in 2018

there are two ways to invest in bitcoin

one is to buy bitcoin directly and wait for it to rise, that is, simply buy it low and sell it high. Judging from the historical data and the popularity of blockchain, there is still a lot of room for bitcoin to rise, but the cost of this investment method is relatively low, and the price of bitcoin fluctuates too much, so although the income of buying bitcoin directly is high, But the risk is also great

the other is to "dig" bitcoin with professional equipment. The total amount of bitcoin is 21 million. mining is the only way to get bitcoin, that is, through a professional computer, which is called mining machine in the instry, to get bitcoin through a lot of calculation, and then sell bitcoin to get income. At present, the price of a mining machine is about 10000, Another problem is the cost of electricity. This kind of equipment consumes a lot of power and needs 24-hour uninterrupted operation, so after a long time, the electricity cost is not a small cost

at present, there are many people engaged in mining, mostly in the form of mines, finding cheap electricity for centralized mining to rece costs

every day will generate income, the highest is more than 200. In addition, the fluctuation of the currency price has little impact on the mining, because the bitcoin can be sold at any price. Even if the price of the coin is low, it can be sold after the price rises. Therefore, the investment income is relatively stable, the risk is relatively low, and the current machine price is also low, There is no threshold for investment, so it is a good opportunity for investment

According to the current market, mining income is not high, and even some retail investors have caused losses, but it is difficult to lose money in large-scale professional mines. Mining requires the cost of machinery and equipment and the cost of electricity price. With the decline of bitcoin market, the cost of machinery has been reced again and again, and the electricity price in large mines is also extremely low. Therefore, the income of mining in large mines will be higher than the cost for a long time in the future, and the income will be higher after the price of bitcoin rises

compared with self built mines, it has certain advantages to invest in mining machinery trusteeship business. Firstly, the time cost is saved to a certain extent, and the mining business can be started immediately. Secondly, unnecessary expenses, such as labor cost, are saved. Since the custody business concentrates the mining machines of multiple investors in one mine, the labor cost is shared by all investors. Finally, there are cheaper electricity prices. The ultimate goal of hosting enterprises to carry out mining machinery hosting business is to make profits. If they can not get lower than the normal electricity price on the market, it is difficult for hosting enterprises to make profits. Of course, the electricity price given to investors will also be lower than the normal electricity price on the market. Another important advantage is that some trusteeship enterprises are able to cash the virtual currency g up by investors' mining machines directly, which also relieves some investors from the worry that they can't cash the virtual currency

is mining profitable or not? There are several factors affecting the mining income: first, the currency price. The higher the currency price, the more profitable the mining. The second is the difficulty. The slower the difficulty rises, the more profitable the mining will be. The lower the cost, the more profitable the mining. Of course, the cost here refers to the purchasing cost and operating cost of computing power, including labor, network, construction, electricity and so on. The lower the cost, the better. Mining needs to deal with the risk of currency price plummeting, mining difficulty soaring, and mining costs rising. At present, the risk of mining currency speculation is much smaller

now the currency price continues to fall. Some people say that it's better to buy money directly than to buy a miner. In fact, it's not the case. Buying money must bear the risk of currency price falling, and the risk and income coexist, while buying a miner is to "protect the income from drought and flood" and keep the value of money rising; In the absence of rich market experience, the decision to buy money is only the choice of speculators

4. Which kind of virtual currency is not safe, it is recommended to enter with caution!

5.

Chen Weixing does not welcome Zhu Xiaohu to invest in blockchain. I don't think it makes any sense for us ordinary spectators

The < HR / > < blockquote >

block header contains many contents, including the hash of the current block (note that it is the hash of the "block" instead of the whole block), and the hash of the previous block. This means that if the content of the current block changes, or the hash of the previous block changes, the hash of the current block will change

< / blockquote >

first of all, this is the personal grudge between Chen Weixing and Zhu Xiaohu. I think as ordinary people, we should just watch the excitement. Of course, if they fight, we can watch more excitement. But on the whole, this is a problem that has nothing to do with our life and we are not interested in it

in a word, the debate between Chen Weixing and Zhu Xiaohu is actually a seven block chain, which is a debate about whether it is a fraud or a leading technology