Block chain information shielding

1. To be honest, there's no way. Ethereum will exceed 2T, even if only some blocks are synchronized, it will take 20g. And now it's blocked and dissatisfied, and it's bound to collapse

2. Once the information is verified and added to the blockchain, it will be stored permanently. Unless more than 51% of the 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.

3.

1.1. Introction

practitioners in the computer instry should be very familiar with the word hash. Hash can realize the mapping of data from one dimension to another, and hash function is usually used to realize this mapping. Generally, y = hash (x) is used in the instry. The hash function can calculate a hash value y by calculating X
hash function characteristics in blockchain:

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function parameters are string type

fixed size output

is computationally efficient

collision free means that the conflict probability is small: X= y => hash(x) != Hash (y)

hide the original information: for example, the verification of transactions between nodes in the blockchain only needs to verify the information entropy of the transaction, and does not need to compare the original information. The nodes do not need to transmit the original data of the transaction, only the hash of the transaction, Common algorithms include Sha series and MD5

1.2. Hash is widely used in blockchain. One of them is called hash pointer
hash pointer, which means that the value of the variable is calculated from the actual data and points to the actual data location, That is, it can not only represent the actual data content, but also the storage location of the actual data. The figure below shows the schematic diagram of hash pointer

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4. The distributed architecture and tamper proof features of blockchain technology help to solve the problems of bill authenticity and information opacity. When participants need to check whether the bill has been tampered or transferred, blockchain can provide indisputable proof of consistency
digital currency also makes use of this feature of blockchain. Puyin is a kind of tea standard digital currency developed based on blockchain technology.

5. 3S technology is the general name of remote sensing (RS), geographic information systems (GIS) and global positioning systems (GPS). It is the combination of space technology, sensor technology, satellite positioning and navigation technology, computer technology and communication technology, Multi disciplinary highly integrated modern information technology for spatial information collection, processing, management, analysis, expression, dissemination and application. 3S technology is the forerunner of modern technology development, plays an important role in the progress of science and technology all over the world, and also has a very wide range of applications in the field of agriculture.

6. Block head, transaction details, transaction counter and block size... Are these Shenma things
blockchain is the big ledger of bitcoin network, and each block is equivalent to a page in the ledger. What information is recorded in the "account book"? At present, each block of bitcoin mainly records data such as block head, transaction details, transaction counter and block size
"block header" contains all information except transaction information, mainly including the hash value of the previous block header, which is used to ensure that blocks are connected in sequence; Time stamp: record the generation time of the block; Random number: that is, the answer to the arithmetic problem of PK for all miners in the whole network; Difficulty target: score the difficulty coefficient of the arithmetic problem
"transaction details" records in detail the transferor, income party, amount and digital signature of the transferor of each transaction, which is the main content of each block
"transaction counter" describes the number of transactions contained in each block
"block size" refers to the size of each block data. Currently, each block is limited to 1MB, which does not rule out the possibility of expansion in the future.

7. A new type of blockchain has been developed to make the public transactions used for verification contain only part of the information
Cooper takes interest rate swap as an example. Dodd Frank requires both parties to record 140 data fields. However, in the blockchain, other banks can only see specific data points, and they may just display the code of transaction nature and price range
at the same time, the blockchain will store complete transactions, which can only be seen by relevant parties and regulators with monitoring obligations
of course, the most important thing about blockchain is that it can not be tampered with, and the protection of intellectual property rights is very important, such as the recent foreign project of decent, which is a distributed content publishing platform.

8. No. Now the communication instry is developed, but personal information leakage is serious. It's normal to have such worries, which shows that people's self-protection awareness has improved. But the proct source chain is a high-tech, using the blockchain encryption technology, will completely encrypt the user's personal information, protect the security of the user's personal information, so, don't worry about this.