Zero value of blockchain

1.

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 key

2. Many relationships between people are based on trust, such as friend relationship, cooperation relationship, transaction relationship, etc
take trading activities as an example. In the past, the two sides who did not trust each other usually chose an intermediary to guarantee a transaction. In the mobile Internet era, we chose Taobao shopping because Alipay provided us with an intermediate guarantee. We chose to drop dripping because it provided us with information matching.
however, these intermediaries are centralized and have their own interests. Sometimes they are not so reliable and trustworthy. Theoretically, Alipay's centralization of accounting has been artificially falsified. Part of the reason for Didi's troubles is that they only think from their own standpoint
what blockchain does is the machine of trust, which replaces the role of trust intermediary with code, ensures the fairness and justice of the whole system through consensus mechanism and distributed accounting, and provides a trust without trust
for example, in the future, people can abandon the intermediate platform and realize point-to-point docking and free trading through blockchain. Shopping does not need to go through an intermediary, and taking a taxi does not need to go through Didi. In this way, we can really achieve "no middleman to earn the price difference" and rece the cost.

3.

Often when we talk about value, we will naturally relate to price. Indeed, price is an important data to measure value. As a blockchain technology, bitcoin's price reached 140000 RMB when it was high, and now it has dropped by about 50%, but it is still as high as 80000 RMB

At this point, you may have understood: if people do not have a common understanding of a thing, and do not give value to a thing, many things will not become "valuable". Just like our understanding of air and food, it is necessary for us to live and survive! This is the "consensus". We all believe that if we want to live, these two are indispensable! Therefore, we can conclude that the essence of value is consensus. What is the value consensus of virtual currency? Most people think that the essence of currency is not consensus, but the credibility and authority of the ruling government. This is not unreasonable. The government can only be one of the sources of value consensus, so most people think it is not comprehensive. In today's society, our consensus on the value of things comes from many ways, such as: Endorsement of authoritative institutions, corporate credit, religious belief, support of scientific theory

4. Indivials can buy and sell bitcoin at their own risk

5. Most of the instrial parks have been established in the past two years, that is, the business hours are only one or two years. The main profit model still relies on obtaining policy subsidy funds. The main reason is that the blockchain application has not been actually implemented. I believe the situation will be better in the next two years. Now there is a blockchain project in Changsha high tech new area, which is called SMIC blockchain service platform, It is a government enterprise service platform, cooperating with Bank of Changsha, Dean justice, etc., and now it is the stage of collecting enterprises on the chain.

6. 1. When building a set of accounts
2. An account set has only one functional currency. If you want to record multiple currencies in the transaction processing layer, use MRC; If it is not needed, it can be realized with conversion function or account set consolidation function
3. Of course, foreign exchange adjustment is for the reporting currency, so the report of each reporting currency should be the result of revaluation.

7. Yunnan metallurgy used to be called Gejiu Yunxi company, Dongchuan Mining Bureau, Yimen copper mine and Huize Lead zinc mine.

8. Yes, but it's better to have your own arms. Where there is no gun, the security is relatively poor. Gold is a thing that can easily make people crazy. You can go to the website of amanbo to have a look. There is a lot of information. I wish you good luck and hope to adopt it. Thank you!!

9. Let me summarize to the building owners that we can use the token to encourage and govern. For example, we can use weni to mobilize various types of community user groups and partners to build an ecosystem of consensus, sharing, win-win and autonomy.