Ethereum tutorial 2017
just like bitcoin, Ethereum is neither controlled nor owned by anyone - it is an open source project created by many people around the world. Different from bitcoin protocol, Ethereum's design is very flexible and adaptable. It is very easy to create new applications on the Ethereum platform. With the release of homestead, anyone can use the applications on this platform safely
Ethereum is a programmable blockchain. It does not give users a series of preset operations, but allows users to create complex operations according to their own wishes. In this way, it can be used as a platform for many types of decentralized blockchain applications
in a narrow sense, Ethereum refers to a series of protocols that define a decentralized application platform. The core of Ethereum is Ethereum virtual machine (EVM), which can encode any complex algorithm. In computer science terminology, Ethereum is "Turing complete.". Developers can use the existing JavaScript and python as the model of other friendly programming languages to create applications running on the Ethereum simulator.
what is Ethereum:
Ethereum is an innovation based on the application of technologies and concepts in bitcoin to computers. Ethereum itself imitates a lot of bitcoin technology to maintain the computer platform. Blockchain technology is one of them
Ethereum platform can safely run any program users want
advantages of Ethereum over other competitive currencies before Ethereum appeared, some digital currencies imitated bitcoin. However, these projects have their own shortcomings, they can only support one or several specific applications at the same time< However, the reason why Ethereum can surpass the limitations of these projects in the past is because of the core idea of Ethereum
what Ethereum wants to implement is a blockchain protocol with built-in programming language. Since it supports programming language, in theory, any blockchain application can be defined with this language, and then run on Ethereum's blockchain protocol as an application
The design of Ethereum is very flexible and adaptable
Ethereum target sets the advantages of blockchain technology, in order to add the advantages of blockchain, such as decentralization, openness and security, to almost all computing fields
blockchain applications of Ethereum
Ethereum has many blockchain applications, such as digital applications of gold and stocks, financial derivatives applications, DNS and digital authentication, etc
Ethereum has achieved more than 100 blockchain applications by many start-ups
Ethereum has also been closely watched by some financial institutions, banking consortia (such as R3), as well as large companies like Samsung, Deloitte, RWE and IBM. As a result, a number of blockchain applications such as simplified and automated financial transactions, merchant loyalty index tracking, and gift cards designed to achieve decentralization of electronic transactions have emerged
the relationship between Ethereum and blockchain:
Ethereum is a programmable blockchain
Ethereum does not give users a series of preset operations (such as bitcoin transaction), but allows users to create complex operations according to their own wishes
in this way, Ethereum can be used as a platform for various types of decentralized blockchain applications, including but not limited to cryptocurrency
like other blockchains, Ethereum also has a peer-to-peer network protocol. Ethereum blockchain database is maintained and updated by many nodes connected to the network. Each network node runs the Ethereum simulator and executes the same instructions. Therefore, people sometimes call Ethereum "world computer"
Ethereum is an open source public blockchain platform with smart contract function. It provides decentralized virtual machine (Ethereum virtual machine) to process point-to-point contract through its special cryptocurrency ether (also known as "Ethereum")
The token on theblockchain is called ether, and the code is eth. It can be traded in many foreign exchange markets of cryptocurrency, and it is also the medium used to pay transaction fees and computing services on Ethereum
the concept of Ethereum was first proposed by vitalik buterin, a programmer, from 2013 to 2014, inspired by bitcoin, with the general meaning of "next generation cryptocurrency and decentralized application platform", and began to develop through ICO crowdfunding in 2014. As of February 2018, Ethernet is the second highest cryptocurrency in market value, second only to bitcoin
extended data:
Ethereum platform has no characteristics and value. Like programming languages, it's up to entrepreneurs and developers to decide what to use. However, it is clear that some application types benefit more from the functions of Ethereum than others. Ethereum is especially suitable for those applications that automatically interact directly between points or promote group coordination activities across networks
for example, coordinate the application of point-to-point market, or the automation of complex financial contracts. Bitcoin enables indivials to exchange money without the help of financial institutions, banks or governments. The impact of Ethereum may be more profound
in theory, any complex financial activities or transactions can be automatically and reliably carried out on Ethereum with coding. In addition to financial applications, any application scenario with high requirements for trust, security and persistence, such as asset registration, voting, management and Internet of things, will be affected by Ethereum platform on a large scale
etc (Ethereum Classic) is a bifurcated currency that Ethereum hard bifurcates after 1920000 blocks, and its function is very similar to Ethereum. Etc adheres to the concept of decentralization and supports the consensus mechanism of blockchain guarantee. Etc firmly believes that once the blockchain starts to run, its development direction will not be controlled by any central team, but will be determined by the consensus of the people participating in the whole network and the consensus of the computing power of the whole network
the Ethereum blockchain hard branching in July 2016 aims to transfer the Dao funds stolen by hackers to an account controlled by investors, and let the old transaction records be forgotten by history. Most Ethereum developers are involved in the reversal, as are exchanges, startups and other members of the ecosystem. A few days later, the project returned to normal. But not everyone wants to forget the old record. As a result, a small number of miners continued to use the original blockchain as a protest. They described the hard fork as a capital withdrawal for the abandoned project of the Dao. So Ethereum classic (etc) was born
2. Detailed parameters
Chinese Name: Ethereum classic English Name: Ethereum classic English abbreviation: etc
developer: Ethereum Classic team core algorithm: ethash consensus proof: POW
release date: 2016 / 7 / 20 block time: About 15-17 seconds / block
total currency: fixed at 210 million, up to 230 million, Every 5 million blocks decelerate by 20%, and the first proction rection is expected to be in December 2017
main features: independent cryptocurrency
If you want to query the transaction records on the main network, you can use Etherscan. However, if you build your own private chain, how should you query the transaction records
the answer is that you need to listen to the logs on the chain, save them in the database, and then query them in the database. For example:
< pre t = "code" L = "Java" > varaddr = & quot& quot;< br />varfilter=web3.eth.filter({fromB lock:0 ,toBlock:' latest', address:addr });< br />filter.get(function(err,transactions){transactions.forEach(function(tx){
vartxInfo=web3.eth.getTransaction(tx.transactionHash);
/ / at this time, the transaction information txinfo can be stored in the database
})< br />});
Web3. Eth. Filter() is used to monitor the log on the chain, and Web3. Eth. Gettransaction() is used to extract the information of the specified transaction. Once the transaction information is obtained, it can be stored in the database for query
recommend a practical introction, you can see: Ethereum tutorial
Log in to the official website, click the "recharge" button on the top right of the page, in the [recharge withdrawal] mole, click [eth] - [eth recharge], select the default recharge account as [RMB spot account], check your recharge address, and then recharge through Ethereum wallet
expansion:
1. Ethereum is not an organization, but an underlying system that can realize intelligent contract and open source on the blockchain. From its birth to may 2017, Ethereum has more than 200 Ethereum applications around the world in just three and a half years. Ethereum is a platform and a programming language, which enables developers to build and release the next generation of distributed applications
Ethereum can be used to program, distribute, guarantee and trade anything: voting, domain names, financial exchanges, crowdfunding, corporate management, contracts and most of the agreements, intellectual property, and smart assets that benefit from hardware integration. On June 12, 2017, the price of Ethernet currency broke through $400, a record high. From $8 in February 2017 to $400 on June 15, 2017, the price of Ethernet currency has increased 50 times. At the same time, the price of bitcoin has eased, 10% lower than the previous peak, and the price of ether coin is much better; Take over & quot; Bitcoin continues to soarEthereum specifies the JSON RPC API application development interface that each node needs to implement. This interface is transport independent. Applications can use this interface protocol to operate Ethereum nodes through HTTP, websocket or IPC and other communication mechanisms:
on cryptokitties, you can buy virtual cats. By 17:00 Beijing time on December 6, 2017, the cheapest kitten had reached 0.037eth. Equivalent to 110 yuan per piece
then the kittens have some opinions about the generation. For example, Gen 12 indicates that it is the 12th generation, while Gen 20 indicates that it is the 20th generation. Generally speaking, the smaller the algebra, the more valuable it is. And you can make your kittens slap each other. For example, a Gen 1 kitten and a Gen 1 kitten will give birth to a Gen 2 kitten
you can sell your kittens and their offspring for money
but what if you don't have two kittens? If you only buy one kitten, you can use your kitten to have fun with other people's high-quality kittens. The fee also depends on the kittens (to be honest, this mechanism is very evil, similar to... Borrowing chickens to have children?) The quality of the proct. If your kitten is of high quality, you can also use your kitten to mate other people's kittens, and then you get Ethereum income
but kittens also have special fertility rates
every time a kitten gives birth to one generation, it will have a certain cooling time, and it can't regenerate kittens within the cooling time,
the cooling time is divided into several grades
fast: 1 minute
swift: 2 – 5 minutes
snappy: 10 – 30 minutes
brisk: 1 – 2 minutes
plodding: 4 – 8 minutes
slow: 16 – 24 minutes
sluggi Sh (lazy kitten): 2 – 4 days
catatonic (nervous kitten): 1 week
so the price of your cat also depends on its birth time
and generally speaking, the larger the algebra is, the higher the gen value is, and the slower their growth rate is
but I want to make complaints about it because CryptoKitties is too hot! Ethereum network has a little bit of a crash, the official recommended that every time you buy a cat, the minimum handling charge is 21000. 400000 fuel = 0.01eth. However, it is irritating that I raised the procere to 1.6 million fuel, which is 0.04, and Ethereum still failed. 0.04 Ethereum. That's more than 120 yuan. It's too dark.