Decentralized autonomous organization

2. Dao (data access object) data access object is an object-oriented database interface, which can also be called its decentralized self-made organization. It reveals the Microsoft Jet database engine (used by Microsoft Access), and allows visual basic developers to connect directly to access tables through ODBC as if they were directly connected to other databases. Dao is most suitable for single system application or small local distribution.

3. It can be regarded as a company that operates without any human intervention and gives all forms of control to a set of unbreakable business rules.

4.

There is an essential difference between Ethereum and bitcoin. What is the difference? Bitcoin defines a set of currency system, while Ethereum focuses on building a main chain (which can be understood as a road) to allow a large number of blockchain applications to run on this road

from this point of view, Ethereum's application scenarios are more extensive, which is why we say that Ethereum marks a simple monetary system in the era of blockchain

1.0, and a transformation to other instries and application scenarios in the era of blockchain 2.0

however, there is no perfect thing in the world. Although Ethereum has expanded the application scope of blockchain in all walks of life and improved the speed of transaction processing, it also has some disputes and doubts

first, the solution to the lack of scalability of Ethereum: slicing technology and lightning network

the bottom design of Ethereum, the biggest problem is that Ethereum has only one chain and no side chain, which means that all programs have to run on this chain equally, consuming resources and causing system congestion. Just like last year's very popular Ethereum game "encryption cat", when this game was very popular, it once caused Ethereum network paralysis

to improve the processing capacity, Ethereum proposes two ways: shard and lightning network. Let's introce these two technologies respectively

(1) fragmentation technology

vitalik buterin, founder of Ethereum, believes that the reason why mainstream blockchain networks such as bitcoin process transactions very slowly is that every miner has to process every transaction in the whole network, which is actually very inefficient. The idea of fragmentation technology is: a transaction does not need to be processed by all nodes in the whole network, as long as some nodes (miners) in the network are allowed to process it. Therefore, Ethereum network is divided into many pieces. At the same time, each piece can handle different transactions. In this way, the network performance will be greatly improved

however, the slicing technology is also controversial. As we all know, the important idea of blockchain technology is decentralization. Only when the whole network witnesses (processes) the same transaction can it have the highest authority. The Ethereum slicing technology is similar to the group witness, not all nodes witness together. In this way, it will lose the absolute "decentralization" attribute, and can only achieve the purpose of high performance by sacrificing certain characteristics of decentralization

(2) lightning network

lightning network uses the way of transaction under the chain. What does that mean? It means: when the participants of lightning network transfer money to each other, they do not need to confirm the transaction through the main chain of Ethereum, but create a payment channel between the participants and complete it under the chain

however, lightning network is not separated from the main chain. Before establishing a payment channel, you need to use the assets on the main chain as collateral to generate a balance proof, which indicates that you can transfer the corresponding balance. In the case that both parties of the transaction hold the balance certificate, both parties can make unlimited number of transfers under the chain through the payment channel

only when the off chain transaction is completed and the assets need to be transferred back to the chain, the balance change information of the main chain account will be registered on the Ethereum main chain, and no matter how many transactions occur ring this period, there will be no record on the main chain

another real benefit of lightning network is that it can save the cost of miners for you. At present, when we trade on the main chain of Ethereum, we need to consume gas and pay for miners. Once we move the transaction to the lower chain, we can save this part of the cost

Of course, lightning network is not perfect. When using the lightning network, the assets on the main chain should be used as collateral; And this part of assets as collateral can not be used before the user completes the transaction under the chain. This also determines that lightning trading is only suitable for small transactions

the above is the problem of insufficient scalability of Ethereum, as well as the two main solutions: fragmentation technology and lightning network

Second, there are loopholes in Ethereum's smart contract and the infamous Dao event

Ethereum's smart contract is very powerful, but there are loopholes in any code. The biggest controversy of Ethereum's smart contract lies in the so-called loopholes, that is, security issues. According to relevant research, 34200 (about 3%) of the nearly 1 million smart contracts based on Ethereum contain security vulnerabilities, which will allow hackers to steal eth, freeze assets or delete contracts, such as the infamous Dao incident

(1) what does Dao mean

before introcing the Dao event, let's first introce what Dao is. Dao is the abbreviation of decentralized

autonomous organization, which can be understood as decentralized autonomous organization. From the perspective of Ethereum, Dao is a kind of contract or a combination of contracts on the blockchain, which is used to replace the government's review and complex intermediate proceres, so as to achieve an efficient and decentralized trust system. Therefore, Dao is not a specific organization, that is to say, there can be many Dao, all kinds of Dao

(2) the infamous Dao event

however, when we talk about Dao now, we basically refer to the Dao event, that is, the infamous hacker attack event we just mentioned. As we know, the English word "the" refers to "the Dao event". The Dao event

refers to "the Dao event", because we just said that Dao is not a specific organization, there can be many Dao, all kinds of Dao

in 2016, slock.it, a German company focusing on "smart locks", launched the Dao project on Ethereum in order to realize decentralized physical exchange (such as apartments and ships). Since April 30, 2016, the financing window has been open for 28 days

unexpectedly, this Dao project is very popular. It raised more than US $100 million in just half a month. By the end of the whole financing period, it raised a total of US $150 million. Therefore, it has become the largest crowdfunding project in history. However, it didn't last long. In June, hackers took advantage of the loopholes in the smart contract to successfully transfer more than 3.6 million Ethernet coins and put them into a Dao sub organization, which has the same structure as the Dao. At that time, the price of Ethernet currency fell directly from more than $20 to less than $13

this event shows that there are loopholes in smart contracts, and once the loopholes are exploited by hackers, the consequences will be very serious. This is why many people criticize Ethereum and say that its smart contract is not smart

to solve this problem, many foreign companies begin to provide code audit services in order to solve the vulnerability problem of smart contract. From a technical point of view, some teams are currently testing smart contracts. Most of these teams are led by professors from Harvard, Stanford and Yale, and some of them have obtained investment from leading institutions

in addition to the problems of insufficient expansibility and loopholes in smart contracts, the controversy over Ethereum lies in the POS consensus mechanism it pursues, that is, the proof of equity mechanism. Under the proof of equity mechanism, if anyone holds more money and holds it for a longer time, he will get more "rights" (interests) and have the opportunity to get bookkeeping power, Bookkeeping can also be rewarded. In this way, it is easy to create the oligarchic advantage of "the stronger the stronger"

Another problem is the chaos of ICO. ICO is a common way to raise funds for blockchain projects, which we can understand as pre-sale. The outbreak of ICO projects on Ethereum has caused illegal activities such as fund allocation and money fraud under the banner of ICO, which has caused security risks to social and financial stability

5. Ethereum, ETH for short. At the end of 2013, vitalik released the white paper of Ethereum, and in July 2014, the pre-sale of Ethereum began. At that time, insiders called this kind of token issue "crowdfunding". Through the 42 day pre-sale, the Ethereum team raised more than 30000 bitcoins through the pre-sale of 60102216 Ethernet coins; In addition, the early contributors who participated in the development before the pre-sale and the developers who have been engaged in project research for a long time are allocated according to 9.9% of the total amount of Ethernet coins sold at that time. So when Ethereum was officially released, there were more than 72 million Ethereum coins. After the end of Ethereum's pre-sale, it uses the proof of work mechanism POW for mining, and rewards the miners according to 26% of the total amount issued at that time every year. In October 2014, Ethereum reced the block output time from 60 seconds to 12 seconds, and now it is basically stable at 15 seconds, with 5 etheric coins awarded for each block
although the pow mining mechanism is adopted, the block out mechanism of Ethereum is different from that of bitcoin. Due to the short block time of Ethereum, Ethereum is easy to form isolated blocks. Isolated blocks refer to the blocks that are not on the longest chain. Bitcoin's isolated blocks have no block rewards, but in Ethereum, isolated blocks can be referenced. The referenced isolated blocks are called "Uncle blocks", and their packaged data will also be recorded in the blockchain. Unlike bitcoin, Ethereum's TERT block has a reward, and each TERT block can get a reward of 4.375 Ethernet coins at most
Ethereum is a programmable and Turing complete blockchain development platform, which is equivalent to a decentralized global computer. In a programming system, there are usually some virtual machines to compile and execute. Java has JVM. In Ethereum, there is also Ethereum's virtual machine EVM, which can execute any complex algorithm code. Developers can use existing programming languages such as JavaScript or Python to create their own applications on Ethereum. Through Ethereum's virtual machine, you can easily issue digital assets, write smart contracts, set up and run decentralized applications, and set up decentralized autonomous organizations
eth is also known as the internal fuel of Ethereum. Unlike currency digital assets, Ethereum is not only used for transfer, but also for payment of smart contracts
in order to prevent the Ethereum blockchain from being full of junk contracts and junk applications, and to establish and run smart contracts on Ethereum, you must use eth to pay for smart contracts. For example, when you transfer your newly created digital assets on the Ethereum blockchain, you need to use eth to pay the handling fee instead of your newly created digital assets.

6.

Blockchain blockchain is a new application mode of computer technology such as distributed data storage, point-to-point transmission, consensus mechanism and cryptocurrency algorithm. Is a shared distributed ledger in which transactions are permanently recorded through additional blocks

2, block - block

in the bitcoin network, data will be permanently recorded in the form of files, which we call blocks. A block is a set of records for some or all of the latest bitcoin transactions and is not recorded by other previous blocks

3. Node -- a of the ledger operated by the participants of the blockchain network

Decentralization is a phenomenon or structure, which can only appear or exist in a system with many nodes or in a group with many indivials. The influence between nodes will form nonlinear causality through the network

5. Consensus mechanism

consensus mechanism is to complete the verification and confirmation of the transaction in a very short time through the voting of special nodes; For a transaction, if several nodes with unrelated interests can reach a consensus, we can think that the whole network can also reach a consensus

6. POW -- proof of work refers to how much money you get depends on the amount of work you contribute to mining. The better the performance of the computer, the more money you will be given

In POS mode, your "mining" income is directly proportional to your currency age, and has nothing to do with the computing performance of the computer

8. Smart contract

smart contract is a kind of computer protocol which aims to spread, verify or execute the contract in an information way. Smart contracts allow trusted transactions without a third party, which are traceable and irreversible

9, time stamp

time stamp refers to the string or encoding information used to identify the recorded time and date. The international standard is ISO 8601

Turing completion refers to the ability of a machine to perform calculations that any other programmable computer can perform

DAPP decentralized application is an open source application that runs automatically, stores its data on the blockchain, motivates it in the form of cryptocurrency token, and operates with protocols showing valuable proof

Dao, a decentralized autonomous organization, can be regarded as a company that operates without any human intervention and gives all forms of control to a set of unbreakable business rules

13. Privatekey - private key

a private key is a string of data that allows you to access a token in a specific wallet. As cryptocurrency, they are hidden except for the owner of the address

14. Publickey -- public key

is paired with private key. The public key can calculate the address of the currency, so it can be used as a certificate to own the address of the currency

15, miner

try to create a block and add it to the computing device or software on the blockchain. In a blockchain network, when a new effective block is created, the system will automatically give the block creator (miner) a certain number of tokens as a reward

16. The mine pool is a fully automatic mining platform, which enables mining machines to contribute their computing power to mine together to create blocks, obtain block rewards, and distribute profits according to the proportion of computing power contribution (that is, mining machines access the mine pool - provide computing power - obtain income)

17, public chain

fully open blockchain, refers to anyone can read, anyone can send transactions and transactions can be effectively confirmed, people all over the world can participate in system maintenance, anyone can read and write data through transactions or mining

18. Private chain

write permission is only for the blockchain of a certain organization or a specific few objects. Read permission can be open to the outside world or restricted to any extent

19, alliance chain

consensus mechanism is a blockchain jointly controlled by several designated institutions

20, side chain

wedged side chains technology, which will realize the transfer of bitcoin and other digital assets between multiple blockchains, which means that users can access the new cryptocurrency system when they use their existing assets

21, cross chain technology

cross chain technology can be understood as a bridge connecting the blockchains, and its main application is to realize atom transaction, asset conversion, information exchange within the blockchain, or solve Oracle problems among the blockchains

22. The hard fork

blockchain has permanent divergence. After the release of the new consensus rules, some nodes that have not been upgraded cannot verify the blocks proced by the upgraded nodes, and usually the hard fork will occur

23, soft forking

when the new consensus rules are released, nodes that have not been upgraded will proce illegal blocks because they do not know the new consensus rules, which will lead to temporary forking

24, hash -- hash value

generally translated as "hash", but also directly transliterated as "hash". In short, it is a function that compresses messages of any length to a message digest of a fixed length

25, main chain

the word "main chain" comes from the main network (, relative to the test network), that is, the officially online and independent blockchain network

for those who don't know the "jargon" in the currency circle, let's learn it as soon as possible:

1. What is legal currency

legal currency is legal tender, which is issued by the state and the government. It is only guaranteed by the government credit, such as RMB, US dollar and so on

2. What is a token

token, usually translated into token. Token is one of the important concepts in blockchain. Its more well-known name is "token". However, in the view of professional "chain circle" people, its more accurate translation is "token", which represents a proof of rights and interests on the blockchain, rather than currency

There are three elements of

token

one is digital proof of rights and interests, which must be in the form of digital certificate of rights and interests, representing a right, an inherent and intrinsic value

The second is cryptocurrency, whose authenticity, tamper proof and privacy protection are guaranteed by cryptocurrency

Third, it can flow in a network, so it can be verified anytime and anywhere

3. What is warehouse building

the establishment of a position in a currency circle is also called opening a position, which refers to a trader's new purchase or sale of a certain amount of digital currency

What is Soha

suoha refers to investing all the principal

What is airdrop

airdrop is a very popular marketing method of cryptocurrency. In order to let potential investors and cryptocurrency enthusiasts get token related information, token teams often air drop tokens

6. What is lockup

position locking generally refers to investors opening a new position opposite to their original position when the market moves in the opposite direction after the sale and purchase contract, which is also called lock, lock order, or even butterfly double flying

What is candy

doughnut candy is a kind of free digital currency issued to users when all kinds of digital currencies are just issued in ICO. It is a kind of momentum and publicity of the project itself by the issuers of virtual currency projects

What is breaking

breaking refers to falling below, and issuing refers to the issuing price of digital currency. Broken currency circle refers to the price of a digital currency falling below the issue price

What is private placement

private placement is a way to invest in cryptocurrency projects, and it is also the best way for cryptocurrency project founders to raise funds for platform operation

What do you think of the K-line diagram

K-line chart is also called candle chart, Japanese line, yin-yang line, bar line, red and black line, etc., commonly referred to as "K-line". It is based on the opening price, the highest price, the lowest price and the closing price of each analysis cycle

What is hedging

General hedging refers to two transactions which are related to the market, opposite in direction, equal in quantity and balanced in profit and loss. In the futures contract market, buy the same number of positions with different directions. When the direction is determined, close out the positions in the opposite direction and keep the positive direction to make profits

What is the position

position is a kind of market agreement, which promises the initial position of the sale and purchase contract, and the buyer is long and in the expected position; The selling contract is short and in the expected position

What are the advantages

good news: refers to the news that the currency gets the attention of the mainstream media, or a breakthrough in the application of a technology, which is concive to stimulating the price rise

14. What is bad news

bad news: news that causes the price of bitcoin to fall, such as technical problems of bitcoin, central bank's crackdown, etc

What is rebound

the phenomenon of currency price rising e to rapid decline in the downward trend. The recovery is less than the decline

What is leverage

leverage trading, as the name suggests, is to use small amount of funds to invest several times the original amount, in order to obtain multiple returns or losses relative to the fluctuations of the investment object