Ethereum smart contract standard
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forsage international crowdfunding, the revolutionary smart contract technology of the new generation platform, originated from the development of Russian technical team, provides distributed market participants with the ability to directly engage in personal and commercial transactions. The smart contract of forsage distributed global shared matrix project is open and can always be viewed on the Ethereum blockchain. These are real smart contracts, which will be implemented on the Ethereum public chain forever without any third party tampering. The global shared matrix project is completely decentralized, aiming to preach Ethereum, so that more players can know Ethereum, smart contracts and forsage code btshijie
what is Ethereum
Ethereum is often compared with bitcoin, but the situation is different. Bitcoin is a kind of cryptocurrency and distributed payment network, which allows bitcoin to be transferred between users
the Ethereum project has a bigger goal. As Ethereum said, "Ethereum is a distributed platform running smart contracts.". These smart contracts run on "Ethereum virtual machine", a distributed computing network composed of all devices running Ethernet nodes
"distributed platform" means that anyone can set up and run an Ethereum node just as anyone can run a bitcoin node. Anyone who wants to run "smart contracts" on nodes must pay the operators of these nodes in ether, which is a cryptocurrency related to Ethereum. Therefore, the person running the Ethernet node provides computing power and gets paid in the Ethernet, which is similar to the way that the person running the bitcoin node provides hash power and pays in bitcoin
in other words, although bitcoin is only a blockchain and payment network, Ethereum is a distributed computing network, and its blockchain can be used for many other things. Details are provided in the Ethereum white paper
what is smart contract
smart contracts are applications that run on Ethereum virtual machines. This is a distributed "world computer" with computing power provided by all Ethereum nodes. Any node providing computing power will pay in ether digital currency as a resource
they are named smart contracts because you can write "contracts" that execute automatically when you meet the requirements
for example, imagine building a KickStarter like crowdfunding service on Ethereum. Someone can set up an Ethereum smart contract to pool funds to others. The smart contract can be written as follows: when $100000 of currency is added to the pool, it will be sent to the recipient. Or, if the $100000 threshold is not reached within a month, all currencies will be returned to the original holder of the currency. Of course, this would use ether instead of dollars
all this will be done according to the smart contract code, which can automatically execute the transaction without the need for a trusted third party to hold the currency and sign the transaction. For example, KickStarter charges 5% above the 5% payment processing fee, which means it will charge $8000 to $10000 for a $100000 crowdfunding project. Smart contracts don't have to pay a fee to a third party like KickStarter
smart contracts can be used for many different things. Developers can create smart contracts to provide functions for other smart contracts, similar to the way software libraries work. Alternatively, smart contracts can simply be used as applications to store information on the Ethereum blockchain
in order to really execute the smart contract code, someone has to send enough Ethernet tokens as the transaction fee - how much depends on the required computing resources. This costs the Ethereum nodes to participate and provide computing power. The global shared matrix project, which is completely decentralized, aims to preach Ethereum and let more players know Ethereum, smart contracts and forsage code btshijie
& quot; A smart contract is a set of promises defined in digital form, including the agreements on which the contract participants can execute these promises& quot;
let's explore the meaning of his definition in more detail
commitment
a set of commitments refers to the (often mutual) rights and obligations agreed by contract participants. These commitments define the nature and purpose of the contract. Take a sales contract as a typical example. The seller promises to deliver the goods and the buyer promises to pay a reasonable price
digital form
digital form means that contracts have to be written into computer-readable code. This is necessary, because as long as the participants reach an agreement, the rights and obligations of smart contract establishment are executed by a computer or computer network
to further explain:
(1) when will the parties to the smart contract reach an agreement? The answer depends on the specific smart contract implementation. Generally speaking, the contract is discovered when the parties are committed to the execution of the contract by installing the contract on the contract host platform< (2) contract execution
& quot; Execute & quot; And the real meaning of it also depends on implementation. Generally speaking, implementation means active implementation through technical means
(3) computer readable code
in addition, the contract needs specific & quot; Digital form & quot; Very much depends on the agreement that the parties agree to use
protocol
protocol is technical implementation, on this basis, the contract commitment is realized, or the contract commitment is recorded. Which agreement to choose depends on many factors, the most important of which is the nature of the assets being traded ring the performance of the contract
take the sales contract as an example. Suppose that the participants agree to pay in bitcoin. The chosen protocol will obviously be bitcoin protocol, on which the smart contract will be implemented. Therefore, the contract must use & quot; Digital form & quot; It's bitcoin scripting language. Bitcoin scripting language is a non Turing complete, imperative, stack based programming language, similar to forth.
although bitcoin can also write smart contracts, the syntax supported by bitcoin is only related to transactions, and there are limited things it can do
therefore, when it comes to writing smart contracts, it usually refers to Ethereum blockchain that supports the execution of Turing complete programs.
The smart contract has been written for a long time
if they can add changes, the description is centralized
the contract is written into the Ethereum smart contract, which is a contradiction sentence
the financial customer service doesn't understand, which is very unreliable
community sites
what is Ethereum
Ethereum is often compared with bitcoin, but the situation is different. Bitcoin is a kind of cryptocurrency and distributed payment network, which allows bitcoin to be transferred between users
related: what is bitcoin? How does it work
Ethereum has a bigger goal. As Ethereum says, "Ethereum is a distributed platform running smart contracts.". These smart contracts run on "Ethereum virtual machine", a distributed computing network composed of all devices running Ethernet nodes
"distributed platform" means that anyone can set up and run an Ethereum node just as anyone can run a bitcoin node. Anyone who wants to run "smart contracts" on nodes must pay the operators of these nodes in ether, which is a cryptocurrency related to Ethereum. Therefore, the person running the Ethernet node provides computing power and gets paid in the Ethernet, which is similar to the way that the person running the bitcoin node provides hash power and pays in bitcoin
in other words, although bitcoin is only a blockchain and payment network, Ethereum is a distributed computing network, and its blockchain can be used for many other things. Details are provided in the Ethereum white paper
what is ether
Ethernet is a digital token (or cryptocurrency) related to Ethereum blockchain. In other words, Ethereum is the token and Ethereum is the platform. But now people often use these terms alternately. For example, coinbase allows you to buy Ethereum, which stands for Ethereum
this is technically "altcoin", which actually means a non bitcoin cryptocurrency. Like bitcoin, ether is supported by distributed blockchain - in this case, Ethereum blockchain
developers who want to create applications or Ethereum smart contracts on Ethereum blockchain need Ethernet token to pay for nodes to host it, while users of Ethereum based applications may need Ethernet to pay for services in these applications. People can also sell services outside the Ethereum network and accept Ethernet payments, or they can sell Ethernet tokens in cash - just like bitcoin
Generally speaking, the steps of deploying smart contract are as follows:
- start an Ethereum node (such as geth or testrpc)
- use Solc to compile smart contracts=& gt; Get the binary code
- deploy the compiled contract to the network This step will consume Ethernet currency, and you need to use the default address or specified address of your node to sign the contract.)=& gt; Get the blockchain address and ABI of the contract (JSON representation of the contract interface, including variables, events and callable methods) The author confused ABI with contract interface here. ABI is the binary representation of the contract interface.)
- use the JavaScript API provided by web3.js to call the contract Depending on the type of call, it may consume Ethernet currency.)
Rc20 token standard (erc20 token standard) is a standard used to create token through Ethereum. According to the erc20 specification, a smart contract can be written to create a "interchangeable token". It is not mandatory, but following this standard, the token created can interact with many exchanges, wallets, etc. it has now been widely accepted by the instry
erc20 token standard was first proposed by Ethereum developer Fabian vogelsteller in the open source community. Later, Ethereum founder vitalik (known as "V God") wrote the first version of the document, which was called "standardized contract API" at that time_ Contract_ APIs
following erc20 token standard, smart contracts can be written. The token methods it needs to implement include: optional name, symbol, decimals, balance of, transfer, transfer from, approve, and allowance. The event responses it needs to implement include transfer, approve
in addition to erc20, Ethereum also focuses on erc721. Different from erc20, erc721 is a non fungible token standard (NFT)
The general syndromes oferc20 are interchangeable and homogeneous, while the general syndromes of erc721 are not interchangeable and heterogeneous; Erc20 can be subdivided infinitely, while erc721 can not be subdivided because its minimum unit is 1
in June 2018, erc721 was officially accepted by Ethereum community and became the final standard. The popular cryptokitties followed the erc721 standard
the Xueshuo innovation blockchain Technology Workstation of Lianqiao ecation online is the only approved "blockchain Technology Specialty" pilot workstation of "smart learning workshop 2020 Xueshuo innovation workstation" launched by the school planning, construction and development center of the Ministry of ecation of China. Based on providing diversified growth paths for students, the professional station promotes the reform of the training mode of the combination of professional degree research, proction, learning and research, and constructs the applied and compound talent training system
Solidness language is a special language for writing and executing smart contracts. It is a contract oriented high-level language running on the basis of Ethereum virtual machine. It was first proposed by the former CTO and co-founder Gavin wood of Ethereum in August 2014. Later, Ethereum developers set up a special team to continuously improve solidness language, At present, it is still under development and optimization. The development storage area on GitHub is HTPs / github.com/thereum/solidness. Here we can learn the most comprehensive details and related documents about the development and iteration process of solidness language. In terms of language style, solid language is deeply influenced by C + +, Python and JavaScript. It is a static programming language, compiled in bytecode mode, so it can run on Ethereum virtual machine. Gavin wood uses the syntax rules of ECMAScript scripting language of JavaScript for reference when developing solid language, which makes it somewhat similar to the existing web development language, but it is quite different. For example, solid language has static type, variable return function and so on. The most important point is that solid language can write contracts with self executing business logic and embedded in smart contracts. Therefore, it is not only one of the basic programming languages of Ethereum, but also the basic programming languages of most other Ethereum based blockchain procts (blockchain 2.0) with smart contracts, It is widely used in the vast majority of blockchain procts, such as hyperledger project, which is developed with soliditv language
the Xueshuo innovation blockchain Technology Workstation of Lianqiao ecation online is the only approved "blockchain Technology Specialty" pilot workstation of "smart learning workshop 2020 Xueshuo innovation workstation" launched by the school planning, construction and development center of the Ministry of ecation of China. Based on providing diversified growth paths for students, the professional station promotes the reform of the training mode of the combination of professional degree research, proction, learning and research, and constructs the applied and compound talent training system