ETH-Ethereum Introduction Details
Ethereum (English: Ethereum) is an open source public blockchain platform with smart contract functions. Through its dedicated cryptocurrency Ether (Ether, also known as "Ethereum"), it provides a decentralized virtual machine (called "Ethereum Virtual Machine") to process peer-to-peer contracts.
The concept of Ethereum was first proposed by programmer Vitalik Butrin from 2013 to 2014 after being inspired by Bitcoin. The concept is "the next generation of cryptocurrency and decentralized application platform", which was crowdfunded through ICO in 2014. To start developing.
As of June 2018, Ethereum is the second highest cryptocurrency by market capitalization. Ethereum is also known as the "second-generation blockchain platform", second only to Bitcoin.

Compared to most other cryptocurrencies or blockchain technologies, the characteristics of Ethereum include the following:
Smart contract: A program stored on the blockchain is run by each node. The person who needs to run the program pays a fee to the node's miners or stakeholders.
Tokens: Smart contracts can create tokens for use in distributed applications. The tokenization of distributed applications aligns the interests of users, investors, and managers. Tokens can also be used for initial token issuance.
Uncle block (uncle block): The shorter block chain that was not included in the parent chain in time because of its slow speed to increase the transaction volume. The related technology of directed acyclic graph is used.
Proof-of-stake (proof-of-stake): Compared with proof of work, it is more efficient, it can save a lot of computer resources wasted in mining, and avoid network centralization caused by special application integrated circuits. (testing)
Plasma: With a smaller branch blockchain operation, only the final result is written to the main chain, which can increase the workload for unit time. (Not yet realized)
State channels: The Thunderbolt network, similar in principle to Bitcoin, can increase transaction speed, reduce the burden on the blockchain, and increase scalability. Not yet realized, the development team includes Raiden Network (Raiden Network) and Mobility Network (Liquidity Network).
Sharding (sharding): reduce the amount of data required for each node to record, and improve efficiency through parallel computing (not yet realized).
Distributed applications: Distributed applications on Ethereum will not be shut down or shut down.

Development History
Ethereum was originally proposed by Vitalik Buterin in 2013. Vitalik was originally a programmer involved in the Bitcoin community. He once proposed to the core Bitcoin developers that the Bitcoin platform should have a more complete programming language for people to develop programs, but they did not obtain their consent, so they decided to develop a The new platform is used for this purpose [8]:88. Buterin believes that many programs can use Bitcoin-like principles to achieve further development. Buterin wrote the "Ethereum White Paper" in 2013, explaining the goal of building a decentralized program. Then, in 2014, through public fundraising through the Internet to obtain development funds, investors used Bitcoin to buy Ether from the foundation.
The Ethereum program was originally developed by a company based in Switzerland, Ethereum Switzerland GmbH [11][12], and later transferred to a non-profit organization "Ethereum Foundation" (Ethereum Foundation).
At the beginning of the development of the platform, some people praised Ethereum's technological innovation, but others questioned its security and scalability.

Bitcoin has created a precedent for decentralized cryptocurrencies, and more than five years have fully tested the feasibility and security of blockchain technology. Bitcoin's blockchain is in fact a distributed database. If you add a symbol-Bitcoin, and specify a protocol so that this symbol can be safely transferred on the database without trusting third parties The combination of these features perfectly constructs a currency transmission system-the Bitcoin network.
However, Bitcoin is not perfect, and the scalability of the protocol is a deficiency. For example, there is only one symbol in the Bitcoin network-Bitcoin, and users cannot customize other symbols. These symbols can represent the company's stock, or Debt certificates, etc., have lost some functions. In addition, the Bitcoin protocol uses a stack-based scripting language. Although this language has some flexibility to enable functions such as multi-signature, it is not enough to build more advanced applications, such as decentralized exchanges. Wait. Ethereum is designed to solve the problem of insufficient scalability of Bitcoin.

In early 2016, Ethereum's technology was recognized by the market, and prices began to skyrocket, attracting a large number of people other than developers to enter the Ethereum world. and OKCoin, two of the top three Bitcoin exchanges in China, officially launched Ethereum on May 31, 2017.
Since entering 2016, those who pay close attention to the digital currency industry have been eagerly observing the development trend of the second-generation cryptocurrency platform Ethereum.
As a relatively new development project using bitcoin technology, Ethereum is committed to implementing a global decentralized and non-ownership digital technology computer to execute peer-to-peer contracts. Simply put, Ethereum is a world computer that you cannot shut down. The innovative combination of encryption architecture and Turing integrity can promote the emergence of a large number of new industries. In turn, the pressure of innovation in traditional industries is increasing, and even faces the risk of elimination.
The Bitcoin network is actually a distributed database, and Ethereum goes further. She can be seen as a distributed computer: the blockchain is the computer's ROM, the contract is the program, and the Ethereum miners It is responsible for computing and plays the role of CPU. This computer is not and cannot be used for free, otherwise anyone can store all kinds of junk information and perform various calculations on it. Using it requires at least a calculation fee and a storage fee, and of course there are other costs. .
The most well-known is the Ethereum Alliance established in early 2017 by more than 20 top global financial institutions and technology companies including JPMorgan Chase, Chicago Board of Exchange, Bank of New York Mellon, Thomson Reuters, Microsoft, Intel, Accenture and so on. The cryptocurrency Ethereum spawned by Ethereum has recently become a sought after asset after Bitcoin.

Ethereum Foundation:
A non-profit foundation headquartered in the Swiss canton of Zug, this fund is an umbrella company responsible for allocating resources to other institutions that promote cryptocurrency research and development in the future. The foundation's board of directors is composed of Vitalik Buterin (Chairman), Mihai Alisie (Vice Chairman), Taylor Gerring, Stephan Tual, Joseph Lubin, Jeffrey Wilcke and Gavin Wood. The foundation will focus on the primary "mission", that is, to enable the operating organization to complete the daily work.

Ethereum Switzerland Co., Ltd.:
A company headquartered in Switzerland, in order to lead the creation of the Genesis Blockchain, will be responsible for part of the operations in 2014. The company is 100% controlled by the Ethereum Foundation and plans to cease operations after the Genesis Blockchain is issued.

Function application
Ethereum is a platform that provides various modules for users to build applications. If building applications is like building a house, then Ethereum provides modules such as walls, roofs, and floors. Users only need to build the house like building blocks. Together, the cost and speed of building applications on Ethereum have greatly improved. Specifically, Ethereum builds applications through a Turing complete scripting language (Ethereum Virtual Machinecode, EVM language for short), which is similar to assembly language. We know that programming directly in assembly language is very painful, but the programming in Ethereum does not need to directly use the EVM language, but is similar to high-level languages ​​such as C language, Python, Lisp, and then converted into EVM language through the compiler.
The application on the platform mentioned above is actually a contract, which is the core of Ethereum. The contract is an automatic agent living in the Ethereum system. He has an Ethereum address. When the user sends a transaction to the contract address, the contract is activated, and then according to the additional information in the transaction, The contract will run its own code and finally return a result, which may be another transaction sent from the contract's address. It should be pointed out that the transaction in Ethereum is not just sending Ether, it can also embed quite a lot of extra information. If a transaction is sent to a contract, then this information is very important, because the contract will complete its own business logic based on this information.
The services that the contract can provide are almost endless, and its boundary is your imagination, because Turing's complete language provides complete freedom for users to build various applications. The white paper cites several examples, such as savings accounts, user-defined sub-currency, etc.

Technological change
At the end of 2013, Ethereum founder Vitalik Buterin released the first white paper of Ethereum. A group of developers who recognized the idea of ​​Ethereum were called in the cryptocurrency community around the world to start the project.
During the period from December 2013 to January 2014, the focus of Ethereum's work was how to launch the vision described by Vitalik in the Ethereum white paper. The team finally thought that Genesis Pre-sale was a good idea. After long-term and multi-level discussions, in order to create a suitable infrastructure and legal strategy, the team decided to postpone the Ethereum pre-sale that was originally held in February 2014.
February 2014 was a very important month for Ethereum, and all aspects of Ethereum are advancing by leaps and bounds: community growth, writing code, writing wiki content, business infrastructure, and legal strategies. This month, Vitalik announced the Ethereum project for the first time at the Bitcoin Conference in Miami and held the first "Ask Us Anything" event on Reddit. The core development team became a world-class cryptocurrency currency team. After the Miami conference, Gavin Wood and Jeffrey Wilcke joined Ethereum for full-time work, although before that, they were completely interested in developing C++ and GO clients for Ethereum.
In early March, Ethereum released the third version of the test network (POC3), and eventually moved its headquarters to Zug, Switzerland. In June, the team released POC4 and quickly moved to POC5. During this period, the team also decided to make Ethereum a non-profit organization. In April, Gavin Wood released the Ethereum Yellow Book, which is an Ethereum technical bible that standardizes important technologies such as the Ethereum Virtual Machine (EVM). In July, the team created the Swiss Ethereum Foundation, released POC5, started the Genesis pre-sale on the 24th, and organized the second "Ask Us Anything" on Reddit.
Since July 24, 2014, Ethereum has carried out a 42-day pre-sale of Ethereum. A total of 31,531 bitcoins were raised. According to the price of bitcoin at the time, it was equivalent to USD 18.43 million, which was the second largest crowdfunding at that time. project. The bitcoin address used during the pre-sale is 36PrZ1KHYMpqSyAQXSG8VwbUiq2EogxLo2, and every transfer in and out can be seen in the Bitcoin blockchain browser. Two weeks before the pre-sale, one bitcoin can buy 2000 ethers, the amount of ethers that one bitcoin can buy decreases with time, and the last week, one bitcoin can buy 1337 ethers. The final amount of Ether sold was 60,102,216. In addition, 0.099x (x = 60102216 is the total amount of the sale) Ether will be allocated to the early contributors who participated in the development before the BTC financing, and another 0.099x will be allocated to the long-term research project. So when Ethereum is officially issued, there are 60102216 + 60102216 * 0.099 * 2 = 72002454 Ether. Since the launch, in the POW (Proof of Work Mechanism) phase, it is planned that up to 60102216 * 0.26=15,626,576 ether will be mined by miners every year. After being converted to POS (Proof of Stake) within 1 to 2 years, the annual output of Ether will be greatly reduced, and even no new coins will be issued.
In the fall of 2014, the harvest season of Ethereum made great progress in both code and operations. POC6 was released on October 5. This is an important version, and one of the highlights is the speed of the blockchain. The block time was reduced from 60 seconds to 12 seconds, and a new GHOST-based protocol was used. In November, Ethereum hosted the first small developer conference (DEVCON 0) in Berlin.
In January 2015, the team released POC7, and in February, the team released POC8. In March, the team released a series of statements regarding the release of the Genesis Block, and POC9 is also under intense development. In May, the team released the last test network (POC9), codenamed Olympic. In order to better test the network, during the Olympic phase, members participating in the test network will receive an Ethereum reward from the team. There are many types of rewards, including test mining rewards and bug submission rewards.
After nearly two rigorous tests, the team released the official Ethereum network at the end of July, which also marked the official operation of the Ethereum blockchain. The release of Ethereum is divided into four stages, namely Frontier, Homestead, Metropolis and Serenity. In the first three stages, the Ethereum consensus algorithm uses a proof-of-work mechanism (POW). In the fourth stage, it will switch to the proof-of-stake mechanism (POS).
On July 30, 2015, Ethereum released the Frontier phase. The Frontier stage is the initial version of Ethereum, not a completely reliable and secure network. Frontier is a blank version of the Ethereum network: an interface for mining and a method of uploading and executing contracts. The main purpose of Frontier is to run mining and exchange transactions, so that the community can run mining equipment, and start to build an environment where people can test distributed applications (DApps). Because the Ethereum client at the Frontier stage has only a command line interface and no graphical interface, it is the main developer at this stage. With the release of Frontier, Ether also began trading on exchanges around the world. At the beginning of 2016, the price of Ether began to skyrocket, and the technical strength of Ethereum began to be recognized in the market, attracting a large number of people other than developers to enter the world of Ethereum.