Rollback in blockchain

2.

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 information of bitcoin network transactions, Used to verify the validity of its information (anti-counterfeiting) and generate the next block

extended data

most blockchain public chains are limited by scalability. The biggest feature of blockchain technology is decentralization, which requires that all accounts in the network need to deal with the accounting process. Distributed accounting has high security, low misoperation rate, political neutrality and correctness

however, blockchain technology embraces these features at the same time, sacrificing scalability, unable to meet the personalized supervision, and slightly insufficient in protecting data privacy. Moreover, with the increase of the number of ledger, the interaction delay will increase exponentially, that is to say, the more ledger in the blockchain network, the higher the delay

3. Blockchain encrypts the transaction information in a transaction block by hash algorithm, and compresses the information into a hash string composed of a string of numbers and letters. Jinwowo group analyzes the functions of its hash algorithm as follows: the hash value of the blockchain can uniquely and accurately identify a block, and any node in the blockchain can obtain the hash value of the block through simple hash calculation, and the calculated hash value does not change, which means that the information in the blockchain has not been tampered with.

4. Blockchain encrypts the transaction information in a transaction block by hash algorithm, and compresses the information into a hash string composed of a string of numbers and letters
jinwowo group analyzes the functions of its hash algorithm as follows:
the hash value of the blockchain can uniquely and accurately identify a block. Any node in the blockchain obtains the hash value of the block through simple hash calculation, and the calculated hash value does not change, which means that the information in the blockchain has not been tampered with.

5.

Public 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

6. The solutions are as follows:
1. Regularly clean the st in the computer, turn off the computer, open the chassis, use a hair dryer and blow with cold air< At ordinary times, 360 guard, Jinshan guard and other tools should be used to clean up the system garbage and temporary files generated by the Internet, and check and kill malicious

Italian software
3. The computer configuration is poor, so try to set the virtual memory as large as possible, and install anti-virus software with less resources, such as NOD32, or only one

auxiliary anti-virus software
4. Try to set the IP to static IP, which can rece the startup time of the computer
5. Don't put too many files and icons on the computer desktop, which will slow down the reaction of the computer. Try not to install the software on disk C
6. Regularly defragment the disk. Open the drive of my computer to defragment - properties - tools

select the disk to be defragmented. Open the "disk defragmenter" window - Analysis - defragmentation - the system will start to defragment

.

7. Probability problem, but I suggest you don't pay first, see clearly. In addition, more observation of that friend's life and your relationship, true or false in such a little information is impossible to judge

8. How to protect my bitcoin after bifurcation
if bitcoin really forks, as an ordinary user, the biggest risk is replay attack
what is replay attack? If bitcoin is split into one or more bitcoins, such as btc1 / btc2 / btc3, each bitcoin account will have a corresponding number of all bifurcated coins according to its bitcoin balance
because the address, private key, algorithm, etc. on each chain are the same, and the transaction format is also the same, the transaction initiated on one blockchain can be broadcast on another blockchain and may be confirmed. This is the "replay attack."
in short, when you transfer btc1, your btc2 / btc3 may also be transferred at the same time
however, at present, many forked coins have done two-way anti replay attack processing to avoid the risk of replay attack after forking.

9. Replay is also called replay. As the name suggests, it means that the same message or data is sent twice or more. If the receiver does not take relevant measures to continuously receive the information, it will not be able to effectively identify that the data has been received, which will bring replay vulnerability. Replay attacks mainly occur after the forking of the blockchain, because the two sides after the forking still keep the data before the forking, so the same transaction can be done on both sides after the forking, so it is difficult to distinguish whether the information has been received. Replay attack is mainly used in identity authentication, which can destroy the correctness of authentication, fish in troubled waters, enter the system and steal system data. Although blockchain is considered to be a relatively secure data storage technology at this stage, there are many ways to attack it, so it is also very important for the maintenance of the system. Xuanling technology has a lot of experience in the field of blockchain development, and they have a perfect after-sales maintenance mechanism, which can ensure the maximum security of the system.