Thursday, June 23, 2022

How To Create Smart Contracts In Blockchain

Where Can I Use Smart Contracts

Ethereum Smart Contracts Tutorial | Deploying Smart Contracts | Blockchain Training | Edureka

The times when we will be able to take full advantage of smart contracts are certainly still to come. So far, they are entering our reality relatively slowly, mainly due to the need to adapt or modify many legal norms or systems.

Moreover, smart contracts in the public consciousness are still more associated with the topic of suspicious cryptocurrencies than with the FinTech sector. Nevertheless, it is easy to find a lot of places where smart contracts will work perfectly.

The current giant of the Swiss banking sector UBS has leaned over one of the smart contracts applications. This is the Madrec platform, which aims to make it easier for banks to analyze the vast range of counterparty data and potential credit risk.

Smart contracts can of course also be used in many other areas, for example:

  • the fight against counterfeiting and trade in stolen digital goods
  • tax purposes
  • healthcare
  • payments in e-commerce )
  • automation of orders )
  • real estate sector

Getting Started With An Ethereum Smart Contract

Time to get down to work and build a smart contract!

Weve decided to develop a basic Ethereum smart contract for a blockchain-based marketplace, but youre welcome to come up with your own ideas for smart contracts.

Our team is always ready to help you validate your idea and select the best feature set for your marketplace.Learn how you can benefit from our marketplace development services.

To implement an Ethereum smart contract for a blockchain marketplace, you need the following toolkit:

  • Node.js A JavaScript runtime environment for server-side programming. You need Node.js for testing the functionality of your Ethereum smart contract and ensuring its proper and secure operation. Along with Node.js, you should install a package manager such as Yarn.
  • Truffle A popular Ethereum development framework that allows you to write and test smart contracts. Truffle is written in JavaScript and contains a compiler for the Solidity programming language.Truffle ontract is a JavaScript library that facilitates importing of compiled smart contracts.
  • Ganache CLI An Ethereum remote procedure call client within the Truffle framework formerly known as TestRPC.
  • Web3.js An Ethereum JavaScript API that communicates with the Ethereum network through RPC calls.
  • Parity A fast and secure Ethereum client for managing accounts, tokens, and so on.
  • Visual Studio Code A functional code editor in fact, youre welcome to use any other editor.

Ok Lets See What Ive Managed To Build

First of all, lets start by introducing my simple Smart Contract. It is a PiggyBank. You can check the code here. With PiggyBank, you can lock your xEGLD tokens , check the number of locked tokens, and withdraw your tokens after the expiration of the lock date. The lock timestamp is configured when creating the Piggy. You would need to pass the Unix timestamp with the date.

Quite simple logic for now, but I plan to add more features like, for example, fee for the Piggy creation or penalty for withdrawal before the lock time. These will be pretty engaging.

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Set Up A Solana Development Environment

Running the smart contract code directly from Windows is confusing for many people. Hence, its recommended to set up a Ubuntu version of WSL so that you can write the code in Windows and then compile the Rust smart contract into a .so file.

Here are the commands to set up the Solana development environment:

apt upgradeapt updateapt install nodejsapt install npmapt install python3-pipcurl --proto '=https' --tlsv1.2 -sSf https://sh.rustup.rs | shsh -c "$"source $HOME/.cargo/envexport PATH="/root/.local/share/solana/install/active_release/bin:$PATH"export RUST_LOG=solana_runtime::system_instruction_processor=trace,solana_runtime::message_processor=debug,solana_bpf_loader=debug,solana_rbpf=debugsolana-test-validator --log

Next, run the Hello World application to test it:

git clone https://github.com/solana-labs/example-helloworld.git  cd example-HelloWorld/npm installnpm run build:program-rust

How To Create A Smart Contract

4 Powerful Non

So far, our guest articles on Antyweb have been created for people who are not developers and are looking for simple explanations of popular topics related to cryptocurrencies and blockchain. We tried to dress the discussed topics in non-technical language and easily assimilable for people who do not work with code on a daily basis.

However, this article is slightly different from our assumptions, because using the opportunity to develop the topic of smart contracts, we also want to show you how to create such a smart contract in a simple way. So, dont be surprised by the fragment of code that you will find below

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Create A Custom Dev Chain For Testing

As part of your TDD, its crucial to quickly and easily run all unit tests to verify that a given change has not altered the expected behavior of a contract. Public testnet Ethereum chains do not generally provide quick enough transaction processing times to make using them for unit tests a good choice . Instead, I rely on a custom proof-of-stake development chain where the block time and the target gas price have both been set to zero. This allows insta-mining of transactions and eliminates the need to fund interacting accounts solely to pay for the transactions cost.

Of course, transaction cost is a real concern when running on a public chain, but a lack of funds is not something that a smart contract function can even respond to. The caller either has the necessary funds to run the transaction or it doesnt and in that case, the code isnt even executed. Such checks then lend themselves to integration testing instead of unit testing, so that a more complete picture of the necessary transaction flow can be considered. A similar development chain could be used for integration testing . But its critical to also run integration tests against a public testchain as a last step in verifying correct operation of your contracts before deployment.

How Smart Contracts Function

Smart contracts is a term used to describe computer code that automatically executes all or parts of an agreement and is stored on a blockchain-based platform. As discussed further below, the code can either be the sole manifestation of the agreement between the parties or might complement a traditional text-based contract and execute certain provisions, such as transferring funds from Party A to Party B. The code itself is replicated across multiple nodes of a blockchain and, therefore, benefits from the security, permanence and immutability that a blockchain offers. That replication also means that as each new block is added to the blockchain, the code is, in effect, executed. If the parties have indicated, by initiating a transaction, that certain parameters have been met, the code will execute the step triggered by those parameters. If no such transaction has been initiated, the code will not take any steps. Most smart contracts are written in one of the programming languages directly suited for such computer programs, such as Solidity.

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How To Interact With The Smart Contract

There are a couple of ways. The simplest one is to use the previously mentioned erdpy. You’ll see precisely how to do all the operations by reading my blog post. There are also other solutions on which I will write separate articles.

So by using erdpy, you can call the Smart Contract, for example like:

erdpy --verbose contract call  --chain="T" --pem="wallets/walletKey2.pem" --gas-limit=5000000 --function="create_piggy" --arguments 1628619457 --proxy="https://testnet-gateway.elrond.com" --recall-nonce --send

The presented function is just one of the examples. You would also need to interact with other Smart Contract functions, like adding the tokens or withdrawing them. You can find all of the commands in the readme file in the PiggyBank repository. As always, check the walkthrough video.

What Are Smart Contracts

Solidity, Blockchain, and Smart Contract Course Beginner to Expert Python Tutorial

To put it simply, a smart contract is a program running on a blockchain, such as Ethereum. Smart contracts consist of two different parts a collection of code and some data. The code is the functions of the contracts meanwhile, the data is considered the state. These two components of each smart contract reside on a specific address on a blockchain.

For Ethereum, all smart contracts are a type of account. As such, smart contracts have the ability to make transactions and hold a balance. However, they differ from regular accounts in the aspect that there is no user in control. Instead, the smart contract/account is managed by the code within the contract itself.

As the contracts are considered accounts, it is also possible for us as users of the blockchain to interact with all smart contracts. For example, we can submit a transaction, and as a result, the contract will execute the functions in the code. This basically means that the contacts supply a set of rules and then enforce them via the code written by the contract programmer.

To exemplify, a smart contract is often referred to as a digital vending machine. This is quite an accurate analogy since we acquire the desired output through the required input, much like a traditional vending machine.

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Example Of A Smart Contract Solution For Vehicle Insurance

According to Capgemini, using smart contracts in the auto insurance industry could result in $21 billion in annual cost savings globally. This is thanks to the benefits of using smart contracts for insurance such as process automation and reduced overhead in claims handling.

Intellias has helped a blockchain startup develop a smart contract solution for one of the leading European insurance companies. The primary goal of this project was to create a web app to enable online vehicle insurance policy purchases. As a result, the insurance company received a suite of highly scalable smart contract solutions that included a language for defining contract specifications and an operating system for managing and storing insurance smart contracts.

The delivered prototype can insure vehicles electronically, manage auto insurance history, and automatically submit auto insurance claims. This is just one example to prove that insurance industry players are ready to learn how to make smart contracts their main competitive advantage.

Read more:

Building A Smart Contract

Solidity sounds more intimidating than it actually is. The first thing you may notice about the language is the striking resemblance it has to a JavaScript class. There are some subtle differences, though, like the requirement of semicolons and the use of hashing functions. The hashing functions are used to create unique keys and map them to other variables. In our example, we would use them to create unique tickets and map them to the accounts that buy them.

When building your first Ethereum contract we recommend using the development environment at remix.solidity.org. It gives you an interactive environment to deploy your contract and interact with it from different Ethereum accounts. A drop-down menu lets you switch accounts and use any of your contracts function calls by pushing the corresponding buttons.

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Historical Background Of Smart Contracts

Believe it or not, smart contracts long predate blockchain technology. While Ethereum, introduced in 2014, is the most popular implementation of the protocol, cryptographer Nick Szabo established the idea in the 1990s.

Back then, Szabo conceptualized a digital currency called Bit Gold. While the asset was never actually launched, this Bitcoin predecessor highlighted the smart contract use case trustless transactions on the internet. If Web 1.0 was the internet, itself, and Web 2.0 the presence of centralized platforms, then Web 3.0 is the trustless, automated, user-powered version of the digital space.

Many,including the Ethereum website, itself, compare smart contracts to a vending machine. Vending machines serve the purpose of a vendor providing the user with a product, without the need for an actual person to take the money and hand over the item. Smart contracts serve that same purpose but are much more versatile.

Smart contracts have advanced quite a bit over time. They started as simple if-then statements that a programmer can create and implement. However, those with programming knowledge are limited, centralizing these trustless contracts. Fortunately, those same developers are working to solve accessibility problems.

Is A Smart Contract Legally Binding

How do smart contracts work in Blockchain?

Are smart contracts legal?

The main concept behind smart contracts is using programs to administer the stipulations of a contract. It uses of cryptography to guarantee fraud protection, transparency, and anti-tampering.

These digital contracts automatically warrant assumed legality. Theres no specific smart contract law yet.

Smart contracts should be considered assoftware programs that can assume a contractual nature when the engaging parties decide to do so. Theyre a tool to enforce legality. Theyre not by themselves inherently legal instruments.

Three Elements of a Contract

Having said that,a legally-binding smart contract must necessarily fulfill the three elements of a traditional contract.

First, a party must initiate an offer. Second, the counterparty must agree to the offered terms. Third, parties bargain on shared promises and obligations.

Simply put, like in traditional deals, smart contracts must transfer some type of value at a present or upcoming time.

Legal basis

How are smart contracts enforced? There are existing laws that already recognize the use and legal nature of smart contracts. These tools can assure businesses of their legality and security.

For instance, one such law is the Uniform Electronic Signatures Act and Electronic Signatures in Global and National Commerce Act. This existing statute already recognizes, allows, and validates the use of electronic signatures and electronic records. This involves those that use blockchain.

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Amending And Terminating Smart Contracts

At present, there is no simple path to amend a smart contract, creating certain challenges for contracting parties. For example, in a traditional text-based contract, if the parties have mutually agreed to change the parameters of their business deal, or if there is a change in law, the parties quickly can draft an amendment to address that change, or simply alter their course of conduct. Smart contracts currently do not offer such flexibility. Indeed, given that blockchains are immutable, modifying a smart contract is far more complicated than modifying standard software code that does not reside on a blockchain. The result is that amending a smart contract may yield higher transaction costs than amending a text-based contract, and increases the margin of error that the parties will not accurately reflect the modifications they want to make.

Projects are currently underway to create smart contracts that are terminable at any time and more easily amended. While in some ways this is antithetical to the immutable and automated nature of smart contracts, it reflects the fact that smart contracts only will gain commercial acceptance if they reflect the business reality of how contracting parties act.

Delegatecall / Callcode And Libraries

There exists a special variant of a message call, named delegatecallwhich is identical to a message call apart from the fact thatthe code at the target address is executed in the context of the callingcontract and msg.sender and msg.value do not change their values.

This means that a contract can dynamically load code from a differentaddress at runtime. Storage, current address and balance stillrefer to the calling contract, only the code is taken from the called address.

This makes it possible to implement the âlibraryâ feature in Solidity:Reusable library code that can be applied to a contractâs storage, e.g. inorder to implement a complex data structure.

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Building Applications On Top Of Smart Contracts

Users of blockchain-enabled applications do not interact with smart contracts directly. They use a web application which invokes these contracts. I teach several courses that cover both Ethereum smart contracts with Solidity and smart contracts using Hyperledger Fabric. In the Ethereum network, these are called decentralized applications or DApps, and the courses in track 3 explore the Truffle Suite and Ethereum DApps in-depth.

In Hyperledger, the composer tool includes a framework to build such apps using high-level abstractions that are intuitive. This makes it easy to involve non-technical business users in app development. Finally, Microsoft Azure and include their interfaces to build full-fledged blockchain applications within minutes, and these include abstractions on top of smart contracts.

Enabling A Client To Transfer Money To A Smart Contract

What Are Smart Contracts? [Create Ethereum & Blockchain Applications Using Solidity]

A smart contract acts like a separate account that can either send money to a tasker or send it back to a client. But first, a client must be able to send money to the smart contract. At this step, you need to add this functionality to the smart contract.

As usual, start from updating the test file. You should specify that nobody but a client can transfer money to a smart contract and that its impossible for anyone to increase the payAmount:

Now update the smart contract by adding the code that allows a client to transfer money to it:

Dont forget to run tests against the smart contract to check if everything is okay.

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Was Sind Die Drei Wichtigsten Vorteile Von Smart Contracts

Kosteneinsparungen Der automatisierte Prozess reduziert die Kosten deutlich. Vertrauen Unveränderte Buchhaltungsunterlagen bedeuten, dass Transaktionen gesteinigt werden. Backup-Speichergeräte können ausfallen. Smart Contracts duplizieren alle Transaktionen, sodass alle Parteien eine Aufzeichnung der Übergänge haben.

Who This Course Is For:

  • Developers that want to start to develop smart contracts
  • Developers that want to start develop to the WAX blockchain
  • 4.0 Instructor Rating
  • 31,408 Students
  • 22 Courses

I am an “eternal student”, I started programming when I was just 10 years old and to this day I still learning new things every day.

Because of my passion for learning new things I developed a passion to teach as well, I start helping people at Stack Overflow where I am ranked as the top 5% Developer Help for Swift and top 10% Developer Help for iOS.

You will not see my name in many apps as I am the go-to guy to fix problems, I offer my work mainly as a contractor solving problems that the other professional cannot solve.

I start to develop software and give consultancy when I was 15 years old and never stop, today I want to help people. I read other people’s codes every day, code produced by the professionals in the field and I can honestly say they are mostly JUNK, and I want you to be different.

One of my clients tries to use an Udemy iOS course to argue about some strategies he took in his code. After seeing so many WRONG explanations, so much BAD advice I decided to create my own courses. I watch over 15 top-rated courses at Udemy and took no time for me to before I decide to take action

But you have will have just one shot to impress, so make it the right one, learn right, learn it once, make money forever and be proud of your codebase.

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