Blockchain Xiaoxia: 20 million to 20 million
first, how to make a fixed investment
1, why should we make a fixed investment? Because no one can determine where the bottom is, blockchain is high-risk and high-yield, and only through fixed investment can the risk be reced
2. What kind of assets are worth fixed investment
one is hard currency bitcoin, the other is widely used ether currency, and the third is a new currency with good credit endorsement. Team background must be strong
3. When is the fixed time
you can make a fixed investment every week, every two weeks and every month. If you even have trouble making a fixed investment every month, I suggest you stop making money and go to sleep
4, how much capital will be invested
the suggestion of blockchain Dashen laomao is that within the range of 10% ~ 30% of your disposable assets, I will calculate it by 20%. For example, if you have a disposable asset of 100000 yuan, you can arrange 3000 yuan for investment from your income every month. If your fixed investment period is two years, then your total investable capital is 100000 * 20% + 3000 * 24 = 92000 yuan. Divided by 24 months, you can invest 3833 yuan per month and 958 yuan per week< Second, diversify investment
after listening to the sharing of laomao and other gods, the suggestions for blockchain assets are as follows: 50% bitcoin + 15% eth + 15% your favorite small currency + 20% crowdfunding new currency.
the mainstream currency is low-risk and low-income. Small currency is a hobby, and the potential of new currency is huge. Its income will one day become your main asset, such as 1 yuan crowdfunding ant stocks, up to 1400 + yuan. Strong background of the team + pragmatic landing, as long as given the time, in this circle to return a hundred times a thousand times is very normal! Among them, blockchain + finance is the easiest scene to implement, so the projects of asset chain have always been popular
we recommend a popular project, sealchain financial public chain, which directly covers seven financial application scenarios, including Inclusive Finance, supply chain finance, ABS, insurance, equity, corporate bonds and intelligent investment advisory. It is expected to become a black horse in the money circle from 2019 to 2021! And in 2019, the exchange price is only 1 yuan!
Blockchain includes public blockchain, joint (instry) blockchain and private blockchain. Public chain point-to-point e-cash system: bitcoin, smart contract and decentralized application platform: Ethereum
blockchain is a new application mode of distributed data storage, point-to-point transmission, consensus mechanism, encryption algorithm and other computer technologies
blockchain is an important concept of bitcoin. In essence, it is a decentralized database. At the same time, as the underlying technology of bitcoin, it is a series of data blocks generated by using cryptographic methods. Each data block contains a batch of bitcoin network transaction information, Used to verify the validity of its information (anti-counterfeiting) and generate the next block
extended data
according to the different degree of blockchain network centralization, three kinds of blockchains under different application scenarios are differentiated:
1. The blockchain with the whole network open and without user authorization mechanism is called public chain
2. The authorized nodes are allowed to join the network, and the information can be viewed according to the authority. It is often used in the inter agency blockchain, which is called alliance chain or instry chain
3. All the nodes in the network are in the hands of one organization, which is called private chain
alliance chain and private chain are also called licensing chain, and public chain is called non licensing chain
blockchain features
1, decentralization. Blockchain technology does not rely on additional third-party management institutions or hardware facilities, and there is no central control. In addition to the self-contained blockchain itself, each node realizes information self verification, transmission and management through distributed accounting and storage. Decentralization is the most prominent and essential feature of blockchain
2. Openness. Blockchain technology is based on open source. In addition to the private information of all parties involved in the transaction is encrypted, the data of blockchain is open to everyone. Anyone can query blockchain data and develop related applications through the open interface, so the information of the whole system is highly transparent
3. Independence. Based on consensus specifications and Protocols (similar to various mathematical algorithms such as hash algorithm used by bitcoin), the whole blockchain system does not rely on other third parties, and all nodes can automatically and safely verify and exchange data in the system without any human intervention
4. Safety. As long as 51% of all data nodes cannot be controlled, the network data cannot be arbitrarily manipulated and modified, which makes the blockchain itself relatively safe and avoids subjective and artificial data changes
5. Anonymity. Unless there are legal requirements, technically speaking, the identity information of each block node does not need to be disclosed or verified, and the information can be transferred anonymously
One of the characteristics of blockchain projects (especially public chains) is open source. Through open source code, to improve the credibility of the project, so that more people can participate. But the open source code also makes it easier for attackers to attack blockchain system. In the past two years, there have been a number of hacker attacks. Recently, the anonymous currency verge (xvg) was attacked again. The attacker locked a vulnerability in the xvg code, which allowed malicious miners to add false timestamps on the block, and then quickly dig out new blocks. In a few hours, the attacker obtained nearly $1.75 million worth of digital currency. Although the subsequent attack was successfully stopped, no one can guarantee whether the attacker will attack again in the future
of course, blockchain developers can also take some measures
one is to use professional code audit services,
the other is to understand the security coding specifications and take preventive measures
the security of cryptographic algorithm
with the development of quantum computer, it will bring a major security threat to the current cryptosystem. Blockchain mainly relies on elliptic curve public key encryption algorithm to generate digital signature for secure transactions. Currently, the most commonly used ECDSA, RSA, DSA, etc. can not withstand quantum attacks in theory, and there will be greater risks. More and more researchers begin to pay attention to cryptographic algorithms that can resist quantum attacks
of course, in addition to changing the algorithm, there is another way to improve the security:
refer to bitcoin's treatment of public key address to rece the potential risk of public key disclosure. As users, especially bitcoin users, the balance after each transaction is stored in a new address to ensure that the public key of the address where bitcoin funds are stored is not leaked
security of consensus mechanism
the current consensus mechanisms include proof of work (POW), proof of stake (POS), delegated proof of stake (dpos), practical Byzantine fault tolerance (pbft), etc
POW faces 51% attack. Because POW depends on computing power, when the attacker has the advantage of computing power, the probability of finding a new block will be greater than that of other nodes. At this time, the attacker has the ability to cancel the existing transaction. It should be noted that even in this case, the attacker can only modify his own transaction, but not the transaction of other users (the attacker does not have the private key of other users)
in POS, attackers can attack successfully only when they hold more than 51% token, which is more difficult than 51% computing power in pow
in pbft, when the malicious nodes are less than 1 / 3 of the total nodes, the system is secure. Generally speaking, any consensus mechanism has its own conditions. As an attacker, we also need to consider that once the attack is successful, the value of the system will return to zero. At this time, the attacker does not get any other valuable return except destruction
for the designers of blockchain projects, they should understand the advantages and disadvantages of each consensus mechanism, so as to select an appropriate consensus mechanism or design a new consensus mechanism according to the needs of the scene
security of smart contract
smart contract has the advantages of low operation cost and low risk of human intervention, but if there are problems in the design of smart contract, it may bring greater losses. In June 2016, the Dao, the most popular funding project of Ethereum, was attacked. The hacker obtained more than 3.5 million Ethereum coins, which later led to the bifurcation of Ethereum into Eth and etc
there are two aspects of the proposed measures:
one is to audit the security of smart contract, and the other is to follow the principle of smart contract security development
the security development principles of smart contract are: to be prepared for possible errors, to ensure that the code can correctly handle the bugs and vulnerabilities; Release smart contracts carefully, do well in function test and security test, and fully consider the boundary; Keep smart contracts simple; Pay attention to the threat intelligence of blockchain and check and update in time; Be clear about the characteristics of blockchain, such as calling external contracts carefully
security of digital wallet
there are three main security risks in digital wallet: first, design defects. At the end of 2014, a user lost hundreds of digital assets e to a serious random number problem (repeated r value). Second, the digital wallet contains malicious code. Third, the loss of assets caused by the loss or damage of computers and mobile phones
there are four main countermeasures:
one is to ensure the randomness of the private key
The second is to check the hash value before installing the software to ensure that the digital wallet software has not been tampered with The third is to use cold wallet The fourth is to back up the private keyPublic chain, also known as "public chain", refers to the blockchain that anyone in the world can enter the system at any time to read data, send confirmatory transactions and compete for bookkeeping. The public chain is generally considered to be "completely decentralized", because no indivial or institution can control or tamper with the reading and writing of data in it. In terms of application, blockchain public chain mainly includes bitcoin, Ethereum, super ledger, most counterfeit currencies and smart contracts. The ancestor of blockchain public chain is bitcoin blockchain, which has the following characteristics:
1, open source code
upload the code to GitHub, and everyone can get complete blockchain data by downloading, Accept the test of the public
2, complete decentralization
anyone can become a node, each node is open, everyone can participate in the calculation of the blockchain, any node is not permanent, but phased, and any center is not mandatory for nodes. Anyone can read and send transactions, and transactions can be effectively confirmed on the blockchain. Anyone can participate in the consensus process. The consensus process determines whether a block can be added to the blockchain and the exact current state. Everyone can get financial reward from it, which is proportional to their contribution to the consensus process. These public chains are generally considered to be "completely decentralized"
3. Developing decentralized applications
through this public chain, developers can easily develop centralized applications. Public chain can protect the rights and interests of users from the influence of program developers
Jiangling branch of China Telecom Co., Ltd. is a branch (listed) of other limited liability companies incorporated on April 26, 2004. Its registered address is located at No. 98, Jiangling Avenue, Haodong Town, Jiangling County
the unified social credit code / registration number of China Telecom Jiangling branch is 91421024ma4877pe2c, and the enterprise legal person is Wang Huajiang
the business scope of Jiangling branch of China Telecom Co., Ltd. is to operate basic telecommunication services in the administrative region of the city: 800MHz CDMA second generation digital cellular mobile communication service, CDMA2000 third generation digital cellular mobile communication service, LTE / fourth generation digital cellular mobile communication service (TD-LTE / LTE FDD), fifth generation digital cellular mobile communication service, Satellite mobile communication service, satellite fixed communication service (only limited to satellite international special line service), satellite transponder rental and sale service; Fixed network local communication service (including local wireless loop service), fixed network domestic long-distance communication service, fixed network international long-distance communication service, Internet international data transmission service, Internet domestic data transmission service, Internet local data transmission service, international data communication service, public telegram and telex service, 26ghz wireless access facilities service Domestic communication facilities service business; Operate 3.5GHz wireless access facilities service business; Value added telecommunication services: fixed network domestic data transmission services, user resident network services, network hosting services (compared with value-added telecommunication service management) in the second type of basic telecommunication services; domestic Internet virtual private network services, Internet access services in the first type of value-added telecommunication services; online data processing and transaction processing services in the second type of value-added telecommunication services Store and forward services, domestic call center services, information services and wireless data transmission services; In the second category of basic telecommunication services, domestic VSAT earth station communication services (compared with value-added telecommunication services management), Internet data center services and content distribution network services in the first category of value-added telecommunication services; Use the information network to operate music and entertainment procts, game procts (including online game virtual currency distribution), performance plays (festivals), performances, animation procts, and engage in exhibition and competition activities of online cultural procts; Internet map service; Manage the proction, sale, installation, design and construction of system integration, technology development, technology service, technology training, technology consultation, information consultation, equipment and computer software and hardware related to communication and information business; House leasing; Leasing of communication facilities; Design, construction and maintenance of safety technology prevention system; Advertising business
check more information of China Telecom Jiangling branch through aiqicha
2. The school plans to use 480 degrees of electricity in May, but actually uses 60 degrees less. What percentage of the actual electricity saving Fujian Yunxiao Experimental Primary School)
3 At present, there are three water pipes (a, B and C). Pipe a flows out 20% salt water at a flow rate of 4G / s, pipe B flows out 15% salt water at a flow rate of 6G / s, and pipe c flows out water at a flow rate of 10G / s. after pipe C is opened, it does not flow for 2 seconds, then flows for 5 seconds, then stops for 2 seconds, and flows for 5 seconds, After 1 minute, it is closed. What is the salt content of the outflow mixture Foreign Language School Affiliated to Wuhan University)
5 6. Xiaoming used a bag of mung beans as an experiment, in which 100 seeds germinated and 25 seeds did not germinate Wenling City, Zhejiang Province)
look at 4 pages, and the next day, what part of the book Wuxi City, Jiangsu Province)
8. Xiaohua donated 4.2 yuan to the disaster area, 0.4 yuan more than Xiaoli. How much more did Xiaohua donate than Xiaoli Anyang City, Henan Province)
9. What's the actual discount Xianju County, Zhejiang Province)
10. 600 kg of rice has been transported to the canteen for 4 days, 50 kg a day. How many kilos per day do you eat in the remaining five days Jianye District, Nanjing)
11.3 boxes of oranges are 24 kg less than 3 baskets of apples. The average weight of each box of oranges is 20 kg. How many kg does each basket of apples weigh Taizhou City, Zhejiang Province)
12 Shanghai)
13. A 2100 meter long canal has been built in Daqiao township for five days, with an average of 240 meters per day. The remaining tasks should be completed in three days. How many meters should be repaired every day Qinhuai District, Nanjing)
14 Yinchuan Experimental Primary School)
15. There are four teams in a class, each team has 12 young pioneers, in the "Hope Project" donation activities, a total of 240 yuan. How much does each young pioneer donate on average Yucai primary school bought two small soccer balls and 25 long ropes, which cost 408.5 yuan. The price of each small soccer ball is 48 yuan. How much is the price of each long rope Nanchang District, Wuxi City, Jiangsu Province)
17. Wang Hua spent 20 yuan to buy five copies of interesting mathematics and five copies of Story King. It's 2.6 yuan for interesting mathematics and how much is it for Story King Yanta District, Xi'an city)
18. The transport team has to transport 89 tons of goods, 10.5 tons each time for the first three times. The rest will be transported in five times. How many tons will be transported each time Shanghai)
19.4 students played singles for 60 minutes on a table tennis table. How many minutes did each student play on average Jianou City, Fujian Province)
20. In the final exam, the average score of Chinese, mathematics and common sense is 95, and the average score of Chinese and mathematics is 93. How many points did you get in the common sense exam Jiangshan City, Zhejiang Province)
21. Five (1) students planted trees, 26 boys planted 6 trees on average, 24 Girls planted 5 trees on average. How many trees do men and women plant on average Donghu District, Nanchang City)
22. Li Dong bought stationery with 5 yuan. He has spent 1.5 yuan on pencils, and the rest is 0.35 yuan on exercise books. How many exercise books can he buy Shanghai Changqing school)
23; If the children are equally divided into small classes in the kindergarten, each of them can get three; How many children can each of the two classes be divided equally Jianye District, Nanjing)
24. Shixin watch factory originally planned to proce 75 watches a day and complete the task in 12 days. The actual 10 days to complete the task, the actual average daily proction of how many pieces Qingshan school in Wuhan)
25. The experimental primary school carried out the activity of "planting potted flowers in Environmental Protection Week". In the first three days, 114 potted flowers were planted every day on average, and in the last four days, 750 potted flowers were planted in total. How many potted flowers were planted every day in the "Environmental Protection Week" Changsha Experimental Primary School)
the remaining 7.5 hours to complete, the average amount of arable land per hour Yangxin County, Hubei Province)
27. A loom can weave 105 meters in 7 hours. At this speed, how many meters can it weave in 8 hours Lin'an City, Zhejiang Province)
28. How many kilometers can a car travel in three hours Guilin, Guangxi)
16.2kg soybean oil can be extracted from 29.120kg soybean, and how many kg soybean oil can be extracted from 2000kg soybean (Taishun County, Zhejiang Province)
30. Two mills in a processing plant can grind 14.4 tons of flour in 3 hours. According to this calculation, how many tons of flour can the six mills grind in eight hours Jianou City, Fujian Province)
31. A garment factory received the task of procing 1200 shirts, and completed 40% in the first three days. According to this calculation, how many days will it take to complete the task Write out two different solutions (Shouchun school in central Hefei)
32. An engineering team has built 2.8 kilometers of a highway in the first 20 days. According to this calculation, how many days will it take for the remaining 4.2 kilometers to complete the construction (Linhai City, Zhejiang Province)
33. The original plan was to make 360 pieces a day and complete them in 18 days. How many days can we finish the task Qingshan District, Wuhan City)
34. Changfeng electric fan factory plans to proce 2800 electric fans. 672 sets have been proced in the first six days. According to this calculation, how many days will it take to complete the task Baixia District, Nanjing)
35. Yumin primary school runs a factory. It originally planned to bind 21600 exercise books in 12 days, but actually 360 more than the original plan. How many days did it actually take to complete the proction task Hongqiao District, Tianjin)
36. Xiaoqing read a 260 page story book, 20 pages a day for the first three days, if the rest read 25 pages a day, how many days to finish Xining City Central District)
37. The school bought 342 meters of plastic rope to do short skipping rope. First cut 5 pieces of the same length, a total of 9 meters. According to this calculation, how many pieces of plastic rope can do short skipping rope Gulou District, Nanjing)
38. The unit price of two baskets of apples is the same. The first basket weighs 64 kg, and the second basket weighs 48 kg. After both baskets are sold, the remaining apples weigh the same. It is known that the second basket sells 56 yuan less than the first basket. How much yuan can the first basket sell Shouchun school in central Hefei)
39. Shixin watch factory originally planned to proce 1000 watches in 25 days, but actually proced 50 watches a day. How many days ahead of schele did it actually complete the task Kaifeng City, Henan Province)
40. The TV factory plans to proce 1200 sets of TV sets in 30 days. In fact, it proces 10 sets more than planned every day. How many days do it actually complete the task Dongyang City, Zhejiang Province)
41. The clothing factory has to process a batch of school uniforms. The original plan is to proce 250 sets of school uniforms every day, which can be completed in 30 days. In fact, 300 sets of school uniforms are proced every day. How many days are they actually completed (Jingdezhen City, Jiangxi Province)
42. A batch of goods was originally planned to be transported 18 tons per day, which was completed in 84 days, but actually 21 tons per day. How many days does it actually take to complete the transportation (Yinchuan No.21 primary school)
43. The assembly team will assemble a batch of washing machines. It is planned to assemble 27 washing machines every day and complete the task in 20 days. In fact, 30 sets are assembled every day, and it only takes a few days to complete the task Beitang District, Wuxi City, Jiangsu Province)
44. The canteen of Daqing primary school transported 24 tons of coal and planned to burn it for 50 days. In fact, it saves 0.08 tons per day. How many days did it burn Yueqing City, Zhejiang Province)
45. The workshop proces a batch of parts, 65 sets per day. After 12 days of proction, 130 sets are still missing. How many sets are there in total Landslide Road Primary School, Jianghan District, Wuhan City)
46. It is planned that 900 pieces of glazed square bricks with a side length of 30 cm will be used for paving, but how many pieces of square marble with a side length of 50 cm will be used for paving Answer with proportion knowledge) (Donghu District, Nanchang)
47. Bind a batch of the same exercise books. The original plan is to pack 16 pages each, and 250 copies can be bound. If you want to bind 200 copies, how many pages should each be bound (Guilin, Guangxi)
48. The clothing factory originally planned to make 120 suits, each suit using 4.8m cloth. After improving the cutting method, each suit saved 0.3m cloth. How many suits can be made from the cloth saved Shanghai Changqing school)
49 Hongguang farm tools factory proced 600 farm tools in May, 25% more than in April. How many farm tools did it proce in April Qingshan District, Wuhan City)
51. There are 174 female employees in Hongxing textile factory, 6 less than 3 times of male employees. How many employees are there in the whole factory Shaoxing County, Zhejiang Province)
two solutions (Yinchuan Experimental Primary School)
53. There are 86 students in the third grade of Beilei primary school, which is four times less than that of the second grade. How many students are there in the second grade Changsha Experimental Primary School)
54. There are 630 boys in a school, and the ratio of boys to girls is 7:8. How many girls are there in this school Shangcheng District, Hangzhou)
55. On the first day of reading a story book, Zhang Hua read 15% of the whole book, 4 pages less. At this time, the ratio of the number of pages read to the number of remaining pages is 1 ∶ 7. How many pages is the story book Pingyang County, Zhejiang Province)
56; If you take 30 books from the upper layer and put them on the lower layer, then the number of books on the two layers is exactly the same. How many books are there on each shelf Hongkou District, Shanghai)
57. There are 89 books on the first shelf, 16 less than the second shelf. There are 1.5 times more books on the third shelf than on the first and second shelves. How many books are there on the third shelf The ratio of the number of art books to the number of other two books is 1 ∶ 5, and there are 180 reference books and literature books. How many books are there in the bookcase Wuxi City, Jiangsu Province)
59. There are two students a and B. student a has saved 27 yuan. After they each donated 15 yuan to the people in the disaster area, the ratio of the amount of money left by student a and student B is 3:4. How many yuan has student B saved Both Xiaohong and Xiaofang have accumulated some pocket money. The ratio of money they saved was 5:3. In the "support disaster area" donation activity, Xiaohong donated 26 yuan and Xiaofang donated 10 yuan. At this time, they had the same amount of money left. How much did Xiao Hong have Qingshan District, Wuhan City)
61. The school bought back 315 saplings and planned to distribute them to the middle and senior grades according to the ratio of 3:4