How to evaluate blockchain

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Blockchain is a kind of technology, which solves the core "trust" problem in the market economy and reces the trust cost between strangers to a very low level

there is one crucial thing in the market economy, which is "trust". Without trust, no deal can be established. When you go to LAICHANG to buy vegetables, if you don't believe that the pesticide content in vegetable is up to the standard, you won't trade with that dealer; If you buy a bottle of water in a small shop, the clerk will not sell you the water if he doesn't believe that the money you give is real

the traditional small-scale peasant economy is acquaintance economy, and the transaction scale is limited to people who are familiar with each other nearby. If an acquaintance deceives you, he will lose your social relationship and damage his reputation in the whole circle of acquaintances. We believe that acquaintances are less likely to cheat us than strangers

therefore, once we are beyond the scope of acquaintances, we need to use a high cost to identify whether a stranger will cheat me and how to avoid the risk of being cheated. This situation will hinder the transaction and restrict the transaction

in addition, different races, nationalities, cultures, religious beliefs and so on will naturally have this kind of trust problem

in the market economy, why can there be so many transactions between strangers? Because of the birth of a new mechanism to solve the problem of trust in strangers

so far, the most important mechanism to solve the trust problem is the "trust intermediary" organization and mode

as long as you and strangers trust a third-party organization, the trust problem between you can be solved through this third-party organization

this third-party organization, we call it trust intermediary. Both the government and the bank are trust intermediaries

you can sell the goods you have worked hard to proce to a stranger in exchange for a stack of RMB banknotes. It's because the credit of the note issuing bank and the guarantee of the authority of the government guarantee the currency value and effectiveness of the banknotes. Otherwise, sell things, in exchange for a few ordinary paper, who would like to

in the era of global village and Internet, the people who buy your things may be strangers who will not meet and thousands of miles away. Trust is lower, so Alipay assumes the role of trust intermediation. Buyers first pay the goods to Alipay's account. When they receive the goods, they confirm that they are OK, then they agree to sell the goods to the seller. Taobao and other e-commerce have been booming rapidly in just over ten years

trust intermediary is in a central position in the transaction system. All transactions should solve the trust problem through it

However, the cost of trust intermediary itself is often huge

as a trust intermediary, how much transaction tax does the government charge each year? What is the most profitable instry? Financial services. The annual profits of Alipay's ant suit are over ten billion. p> What does this mean? Both sides of the market actually pay a huge trust cost

if there is any way to cancel or greatly rece the trust cost, the transaction cost of the general public can be reced, and the profits can be greatly increased

so in the Internet era, blockchain technology is on the stage

it allows the trading party to get rid of the intermediary, solve the problem of trust among strangers, and greatly rece the cost of trust

the blockchain can be expanded on a large scale, the data is open and transparent, the data of each client is consistent, and even if some clients are destroyed, the data security will not be affected. These highly reliable technical features can solve the trust problem of strangers with low cost

this technology can be extended to all fields that can be digitized, such as digital currency, payment and clearing, digital bills, proof of rights and interests, credit reference, government services, medical records, etc

in the medium and long term, blockchain will be a revolutionary technology, which will bring about great social changes like the existing Internet, and has great investment value and money making opportunities

in the future, the companies that can combine blockchain with different scenarios to promote applications may be the next group of bat, the next Google, Microsoft and apple

as the first practical application of blockchain technology, bitcoin has been widely accepted and used all over the world. Millions of users and tens of thousands of merchants have accepted the payment of bitcoin as a digital currency, and the exchange value of bitcoin as a currency is growing. Even e to the consensus that the total amount is fixed and the long-term value is bullish, bitcoin has become a hedge asset similar to gold, and the price has skyrocketed

3. Private key~

4.

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

5. The traceability and transparency of logistics instry and supply chain management can be effectively improved by using the characteristics of non tampering and distributed storage of blockchain technology information. Logistics is considered to be the area where blockchain is most likely to create value.

6. Blockchain is actually an emerging technology. The simplest thing is to play with digital currency. Now I'm doing it on bitmax. This platform is built by the senior quantitative team of Wall Street, which is very good in terms of security and technology.

7. It's known that it's a Ponzi scheme. Whether the blockchain can be traded or not can be verified by the owner himself. My mother-in-law can't persuade her to do so. She claims that she will go public. After many investigations, I found that the so-called VR maker, namely shede alliance, does not exist. The only two remaining companies are
: China dream shede Group Co., Ltd., registered in Hong Kong, After investigation, it has been cancelled in June, 18, and has no business activities since its registration. TIANCHAO Network Technology Co., Ltd., registered in Shanghai, has a registered capital of only 2 million yuan. Since 2016, it has no relevant financial statements and tax payment records. It is a leather bag company. The website of blockchain company is Io terminated and belongs to the domain name of British Indian Ocean. The maintenance fee is only a few hundred yuan a year
behind the high returns, there are opportunities to kill. Please think twice before you act. If you have invested, I will not say

8. It seemed ill bred, completely devoid of the superiority that Mr. Heathcliff and his wife could see. he