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Build a Custom Bonding Curve for Token Sales with Solidity A bonding curve is a mathematical curve that depicts how pricing and token supply are linked. This bonding curve states that a token's price grows as its supply increases. As numerous individuals become engaged with the initiative and continue to buy tokens, for instance, the cost of each subsequent buyer increases slightly, providing early investors with a chance to profit. If early buyers identify profitable businesses, they may eventually make money if they buy curve-bonded tokens early and then sell them. For more related to crypto exchange, visit our crypto exchange development services.Check this blog |Tokenization of RWA (Real-World Assets): A Comprehensive GuideBonding Curve Design: Key Considerations :Token pricing can be best managed by using unique purchasing and selling curves.Those who adopt first are often entitled to better benefits to promote early support.Inspect for any price manipulation and deploy measures to protect the integrity of the token sale.As the last price system, the bonding curve will ensure that tokens are valued equitably in line with supply and demand.After a rapid initial development phase, your project will probably follow an S-curve growth pattern, resulting in a more stable maturity phase.Aim for an enormous increase in the token's value over time. Pre-mining tokens should be carefully considered and backed by the project's specific requirements.Make sure that token pricing is in line with the project's long-term value proposition and set reasonable fundraising targets.How Bonding Curves Are Used?1. Market PredictionBonding curves are used by platforms such as Augur to generate dynamic markets for upcoming events. The price of each share varies according to market demand, and users can buy shares that reflect particular outcomes.2. Crowdfunding and ICOsFundraising efforts can be streamlined by using bonding curves. For example, during initial coin offerings (ICOs), Bancor's protocol uses a bonding curve to control its token supply. This system ensures liquidity and reduces price volatility by enabling investors to buy tokens at a dynamic pricing.An example of a bonding curve interaction:To enable users to mint or purchase a new token (such as the Bonding Curve Token, or BCT) with a designated reserve currency (let's say CWEB), a smart contract is developed.The price of BCT is algorithmically calculated in relation to its current circulating supply and shown in its reserve currency, CWEB.A smart contract will allow the user to purchase the new BCT token using the reserve currency. The sold CWEB is maintained in the smart contract as collateral and is not distributed to any individual or team.After the user completes their purchase, the price of the token will move along the bonding curve per the amount of supply the user has just created (probably increasing the price for future buyers).The decision to sell or burn a BCT token back to the curve can be made at any time. After their first purchase, the user will probably sell at a profit (less petrol and fees) if the price keeps rising. Following approval of their sale, the smart contract will return the bonded CWEB to the user.Also, Check |Liquid Democracy | Transforming Governance with BlockchainBancor FormulaThe Bancor Formula calculates the price of a Continuous Token as it changes over time. The Reserve Ratio, which is determined as follows, is a constant used in the formula:Reserve Token Balance / (Continuous Token Supply x Continuous Token Price) = Reserve RatioImplementation of Bancor Formula in Solidity : // SPDX-License-Identifier: UNLICENSED pragma solidity ^0.8.27; import "./SafeMath.sol"; import "./Power.sol"; contract BancorFormula is Power { using SafeMath for uint256; uint32 private constant MAX_RESERVE_RATIO = 1000000; function calculatePurchaseReturn( uint256 _supply, uint256 _reserveBalance, uint32 _reserveRatio, uint256 _depositAmount) public view returns (uint256) { // validate input require(_supply > 0 && _reserveBalance > 0 && _reserveRatio > 0 && _reserveRatio <= MAX_RESERVE_RATIO, "Invalid inputs."); // special case for 0 deposit amount if (_depositAmount == 0) { return 0; } // special case if the ratio = 100% if (_reserveRatio == MAX_RESERVE_RATIO) { return _supply.mul(_depositAmount).div(_reserveBalance); } uint256 result; uint8 precision; uint256 baseN = _depositAmount.add(_reserveBalance); (result, precision) = power( baseN, _reserveBalance, _reserveRatio, MAX_RESERVE_RATIO ); uint256 newTokenSupply = _supply.mul(result) >> precision; return newTokenSupply.sub(_supply); } function calculateSaleReturn( uint256 _supply, uint256 _reserveBalance, uint32 _reserveRatio, uint256 _sellAmount) public view returns (uint256) { // validate input require(_supply > 0 && _reserveBalance > 0 && _reserveRatio > 0 && _reserveRatio <= MAX_RESERVE_RATIO && _sellAmount <= _supply, "Invalid inputs."); // special case for 0 sell amount if (_sellAmount == 0) { return 0; } // special case for selling the entire supply if (_sellAmount == _supply) { return _reserveBalance; } // special case if the ratio = 100% if (_reserveRatio == MAX_RESERVE_RATIO) { return _reserveBalance.mul(_sellAmount).div(_supply); } uint256 result; uint8 precision; uint256 baseD = _supply.sub(_sellAmount); (result, precision) = power( _supply, baseD, MAX_RESERVE_RATIO, _reserveRatio ); uint256 oldBalance = _reserveBalance.mul(result); uint256 newBalance = _reserveBalance << precision; return oldBalance.sub(newBalance).div(result); } }Implement Interface of IBondingCurve:// SPDX-License-Identifier: UNLICENSED pragma solidity ^0.8.27; interface IBondingCurve { function getContinuousMintReward(uint _reserveTokenAmount) external view returns (uint); function getContinuousBurnRefund(uint _continuousTokenAmount) external view returns (uint); }Implement Bancor Bonding Curve :// SPDX-License-Identifier: UNLICENSED pragma solidity ^0.8.27; import "../math/BancorFormula.sol"; import "../interface/IBondingCurve.sol"; abstract contract BancorBondingCurve is IBondingCurve, BancorFormula { uint32 public reserveRatio; constructor(uint32 _reserveRatio) { reserveRatio = _reserveRatio; } function getContinuousMintReward(uint _reserveTokenAmount) public view returns (uint) { return calculatePurchaseReturn(continuousSupply(), reserveBalance(), reserveRatio, _reserveTokenAmount); } function getContinuousBurnRefund(uint _continuousTokenAmount) public view returns (uint) { return calculateSaleReturn(continuousSupply(), reserveBalance(), reserveRatio, _continuousTokenAmount); } // These functions are unimplemented in this contract, so mark the contract as abstract function continuousSupply() public view virtual returns (uint); function reserveBalance() public view virtual returns (uint); }ConclusionWe highlighted key considerations for bonding curve design, including the importance of managing token pricing, preventing price manipulation, and aligning the token's value with the long-term goals of the project. By leveraging the Bancor Formula and its implementation in Solidity, we created a model that can adjust token prices dynamically based on supply and demand, while maintaining liquidity and reducing price volatility.At Oodles , we specialize in advanced blockchain solutions, including bonding curves for token sales and DeFi applications.Contact our blockchain developers today to bring your token project to life.

Technology: MEAN , Web3.js more Category: Blockchain Development & Web3 Solutions

Tushar Shrivastava

28 Nov 2024

How to Write and Deploy Modular Smart Contracts Modular contracts enable highly configurable and upgradeable smart contract development, combining ease of use with security. They consist of two main components:Core Contracts: These form the foundation of the modular system, managing key functions, data storage, and logic. Core contracts include access control mechanisms and define interfaces for module interactions.Module Contracts: These add or remove functionalities to/from core contracts dynamically, allowing for flexibility. Modules can be reused across multiple core contracts, enabling upgrades without redeploying the core contract.How They Work: Modules provide additional functionality via callback and fallback functions that interact with core contracts. Fallback functions operate independently, while callback functions augment core contract logic, enhancing dApp functionality.You may also like | How to Create Play-to-Earn Gaming Smart ContractsSetup | Writing and Deploying Modular Smart ContractsInstall Forge from Foundry and add the modular contract framework:forge init forge install https://github.com/thirdweb-dev/modular-contracts.git forge remappings > remappings.txt ContractThe ERC20Core contract is a type of ERC20 token that combines features from both the ModularCore and the standard ERC20 contract. It names the token "Test Token" and uses "TEST" as its symbol, with the deployer being the owner of the contract. A significant feature is the required beforeMint callback, which allows certain actions to be taken before new tokens are created. The mint function lets users create tokens while ensuring the callback is executed first. The BeforeMintCallback interface makes it easier to add custom logic from other contracts. Overall, ERC20Core offers a flexible way to develop custom tokens while maintaining essential ERC20 functions.// SPDX-License-Identifier: UNLICENSED pragma solidity ^0.8.13; import {ModularCore} from "lib/modular-contracts/src/ModularCore.sol"; import {ERC20} from "lib/solady/src/tokens/ERC20.sol"; contract ERC20Core is ModularCore, ERC20 { constructor() { _setOwner(msg.sender); } function name() public view override returns (string memory) { return "Test Token"; } function symbol() public view override returns (string memory) { return "TEST"; } function getSupportedCallbackFunctions() public pure virtual override returns (SupportedCallbackFunction[] memory supportedCallbacks) { supportedCallbacks = new SupportedCallbackFunction[](1); supportedCallbacks[0] = SupportedCallbackFunction(BeforeMintCallback.beforeMint.selector, CallbackMode.REQUIRED); } function mint(address to, uint256 amount) external payable { _executeCallbackFunction( BeforeMintCallback.beforeMint.selector, abi.encodeCall(BeforeMintCallback.beforeMint, (to, amount)) ); _mint(to, amount); } } interface BeforeMintCallback { function beforeMint(address to, uint256 amount) external payable; } Also, Read | ERC 4337 : Account Abstraction for Ethereum Smart Contract WalletsThe PricedMint contract is a modular extension designed for token minting, leveraging Ownable for ownership management and ModularExtension for added functionality. It uses the PricedMintStorage module to maintain a structured storage system for the token price. The owner can set the minting price through the setPricePerUnit method. Before minting, the beforeMint function verifies that the provided ether matches the expected price based on the token quantity. If correct, the ether is transferred to the contract owner. The getExtensionConfig function defines the contract's callback and fallback functions, facilitating integration with other modular components.// SPDX-License-Identifier: UNLICENSED pragma solidity ^0.8.13; import {ModularExtension} from "lib/modular-contracts/src/ModularExtension.sol"; import {Ownable} from "lib/solady/src/auth/Ownable.sol"; library PricedMintStorage { bytes32 public constant PRICED_MINT_STORAGE_POSITION = keccak256(abi.encode(uint256(keccak256("priced.mint")) - 1)) & ~bytes32(uint256(0xff)); struct Data { uint256 pricePerUnit; } function data() internal pure returns (Data storage data_) { bytes32 position = PRICED_MINT_STORAGE_POSITION; assembly { data_.slot := position } } } contract PricedMint is Ownable, ModularExtension { function setPricePerUnit(uint256 price) external onlyOwner { PricedMintStorage.data().pricePerUnit = price; } function beforeMint(address to, uint256 amount) external payable { uint256 pricePerUnit = PricedMintStorage.data().pricePerUnit; uint256 expectedPrice = (amount * pricePerUnit) / 1e18; require(msg.value == expectedPrice, "PricedMint: invalid price sent"); (bool success,) = owner().call{value: msg.value}(""); require(success, "ERC20Core: failed to send value"); } function getExtensionConfig() external pure virtual override returns (ExtensionConfig memory config) { config.callbackFunctions = new CallbackFunction ; config.callbackFunctions[0] = CallbackFunction(this.beforeMint.selector); config.fallbackFunctions = new FallbackFunction ; config.fallbackFunctions[0] = FallbackFunction(this.setPricePerUnit.selector, 0); } } DeployTo deploy the Modular Contract, first get your API Key from the Thirdweb Dashboard. Then run npx thirdweb publish -k "THIRDWEB_API_KEY", replacing "THIRDWEB_API_KEY" with your key. Select "CounterModule," scroll down, click "Next," choose the "Sepolia" network, and click "Publish Contract."For the Core Contract, run npx thirdweb deploy -k "THIRDWEB_API_KEY" in your terminal, replacing "THIRDWEB_API_KEY" with your key. Select "CounterCore," enter the contract owner's address, and click "Deploy Now." Choose the "Sepolia" chain and click "Deploy Now" again to start the deployment.Also, Explore | How to Create a Smart Contract for Lottery SystemConclusionModular contracts represent a design approach in smart contract development that prioritizes flexibility, reusability, and separation of concerns. By breaking down complex functionalities into smaller, interchangeable modules, developers can create more maintainable code and implement updates more easily without losing existing state. Commonly utilized in token standards and decentralized finance (DeFi), modular contracts enhance the creation of decentralized applications (dApps) and promote interoperability, thereby fostering innovation within the blockchain ecosystem. If you are looking for enterprise-grade smart contract development services, connect with our skilled Solidity developers to get started.

Technology: MEAN , PYTHON more Category: Blockchain Development & Web3 Solutions

Mudit Singh

03 Oct 2024

How to Create Play-to-Earn Gaming Smart Contracts The Play-to-Earn (P2E) model is transforming blockchain game development by enabling players to earn real-world value through in-game activities. At the core of this innovation are smart contracts, which power transparent, decentralized economies and ensure trustless gameplay experiences.Comprehending the Essential Components of a Play-to-Earn Smart ContractIn essence, a Play-to-Earn gaming smart contract is a set of pre-established guidelines stored on a blockchain and intended to control game-related transactions, asset ownership, and prizes. The main elements of a standard P2E smart contract are as follows:In-Game RewardsPlayers earn tokens or NFTs as they progress through the game. These rewards can be traded or sold in decentralized markets, offering real-world value to players.Also, Read | Tap-to-Earn Games | An Exhaustive Guide to Rewards-Based GamingAsset OwnershipSmart contracts enable true ownership of in-game assets like characters, skins, or items in the form of NFTs. Unlike traditional games, where assets remain under the game developer's control, NFTs grant players full rights over their possessions.Secure TransactionsThe decentralized nature of blockchain ensures that all transactions, whether token earnings or asset trades, are securely recorded and verifiable.Game GovernanceSome Play-to-Earn games incorporate decentralized governance, allowing players to vote on game updates or economic changes through token staking or governance mechanisms built into the smart contract.InteroperabilityThanks to standardized smart contract protocols, many P2E games strive for cross-game compatibility, allowing players to use their NFTs or tokens in other games.Also, Check | How to Create a Simple Crypto Clicker GameAn Easy Play-to-Earn Gaming Smart Contract in Solidity CodeThis is a basic example of implementing a Play-to-Earn smart contract in Solidity, which is the main Ethereum smart contract programming language. Tokens are awarded to participants under this contract when they perform in-game activities.// SPDX-License-Identifier: MIT pragma solidity ^0.8.0; contract PlayToEarnGame { // Token balance mapping for players mapping(address => uint256) public tokenBalance; // Owner of the contract (game developer) address public owner; // Token reward per task completed uint256 public rewardAmount; // Event to notify when a player earns tokens event TokensEarned(address indexed player, uint256 amount); // Modifier to allow only owner to execute specific functions modifier onlyOwner() { require(msg.sender == owner, "Only the owner can perform this action"); _; } constructor(uint256 _rewardAmount) { owner = msg.sender; // Set the contract deployer as the owner rewardAmount = _rewardAmount; // Initialize the token reward per task } // Function to complete a task and earn tokens function completeTask() external { // Increment the player's token balance tokenBalance[msg.sender] += rewardAmount; // Emit an event to notify of the reward emit TokensEarned(msg.sender, rewardAmount); } // Function for the owner to adjust the reward amount function setRewardAmount(uint256 _newAmount) external onlyOwner { rewardAmount = _newAmount; } // Function to allow players to withdraw their tokens function withdrawTokens() external { uint256 playerBalance = tokenBalance[msg.sender]; require(playerBalance > 0, "You have no tokens to withdraw"); // Transfer the tokens to the player payable(msg.sender).transfer(playerBalance); // Reset the player's balance tokenBalance[msg.sender] = 0; } // Fallback function to accept Ether (could be used to fund rewards) receive() external payable {} }You may also like | How To Create a Daily Game Reward System in SolidityPlay-to-Earn Smart Contracts' FuturePlay-to-earn games are about to cause unheard-of disruptions in the gaming business. We anticipate increasingly intricate incentive structures, tokenized economies, and cross-platform gameplay as blockchain technology develops, all of which will improve the gaming experience. If you are looking to develop your game leveraging these emerging decentralized gaming models, connect with our blockchain game developers to get started.

Technology: SMART CONTRACT , POSTGRESQL more Category: Blockchain Development & Web3 Solutions

Prince Balhara

03 Oct 2024

Understanding Decentralized Oracle Network Development with Chainlink Blockchains, while secure, cannot access real-world data on their own. This limitation creates challenges for blockchain development (dApps) that require external information, like price feeds or weather data. Chainlink, a leading decentralized oracle network (DON), solves this problem by securely connecting smart contracts to off-chain data sources.You may also like | Oracle Development Using Ethereum Smart ContractsHow Chainlink WorksChainlink uses a decentralized network of independent nodes, known as oracles, to fetch, verify, and deliver external data to smart contracts. These oracles bridge the gap between blockchain and real-world information, ensuring data accuracy and preventing tampering. Chainlink's decentralized structure avoids single points of failure, making the system more reliable.Also, check | Blockchain Oracles | Making Smart Contracts Talk to the WorldArchitecture of Chainlink's Decentralized Oracle Network +-----------------------------+ | Decentralized Oracle | | Network (DON) | +-----------------------------+ | +-------------+-------------+ +------------v----------+ +------------v----------+ | Oracle Node 1 | | Oracle Node 2 | | - Fetches data | | - Fetches data | +------------------------+ +------------------------+ | | +------------+----------+ +------------+----------+ | Aggregation Contract | | Aggregation Contract | +------------------------+ +------------------------+ | | +----------v---------+ +------------v--------+ | Smart Contract | | Smart Contract | +---------------------+ +---------------------+ Steps to Build with ChainlinkSmart Contract Development: Create a smart contract specifying the conditions for data requests. Chainlink libraries enable smart contracts to communicate with external oracles.Chainlink Node Setup: Set up oracles to retrieve data from trusted sources like APIs. Multiple nodes ensure decentralization and data accuracy.Requesting Data: Smart contracts send data requests, which Chainlink nodes process by retrieving the required information from external sources.Data Aggregation: The aggregation contract collects and verifies data from different nodes, ensuring accuracy before delivering it to the smart contract.Also, Read | A Comprehensive Guide to Blockchain OracleConclusionChainlink empowers blockchain developers to securely integrate off-chain data into their dApps. Its decentralized oracle network is crucial for industries like DeFi, insurance, and gaming, making Chainlink a vital component for creating trust-minimized, real-world applications. If you are looking to build a decentralized Oracle network with Chainlink to empower your project, connect with our skilled smart contract developers to get started.

Technology: MEAN , PYTHON more Category: Blockchain Development & Web3 Solutions

Jagveer Singh

02 Oct 2024

Integrate Raydium Swap Functionality on a Solana Program Solana is recognized as a top platform for blockchain app development due to its low transaction fees and excellent throughput. With its smooth token swaps, yield farming, and liquidity pools, Raydium is a well-known automated market maker (AMM) and liquidity provider among the many protocols that flourish on Solana. Developers wishing to expand on this dynamic environment have many options when integrating Raydium's switch feature into custom Solana software.Also, Explore | How to Develop a Crypto Swap Aggregator PlatformThis blog will guide you through the process of using the Raydium SDK and the Solana Web3.js framework to integrate the swap functionality of Raydium into your Solana program.You may also like | How to Build a Solana Sniper BotUsing Raydium SDK and Solana Web.js to Integrate Swap Functionality on a Solana ProrgramPrerequisites:Node.js is installed on your machine.Solana CLI installed and configured.Basic knowledge of TypeScript and Solana development.A basic understanding of how Raydium works.Setting Up the Environment:npm init -ynpm install @solana/web3.js @solana/spl-token @raydium-io/raydium-sdk decimal.js fs@solana/web3.js: The official Solana JavaScript SDK.@solana/spl-token: A library for interacting with the Solana Program Library (SPL) tokens.@raydium-io/raydium-sdk: The Raydium SDK interacts with the protocol's AMM and liquidity pools.decimal.js: A library for handling arbitrary-precision decimal arithmetic.Also, Explore | SPL-404 Token Standard | Enhancing Utility in the Solana EcosystemConnect with Solana Clusterimport { Connection, clusterApiUrl, Keypair, PublicKey, Transaction } from '@solana/web3.js'; const connection = new Connection(clusterApiUrl('devnet'), 'confirmed'); console.log("Connected to Solana Devnet");Payer's Keypair Loading:import * as fs from 'fs'; const data = fs.readFileSync('./secret.json', 'utf8'); const secretKey = Uint8Array.from(JSON.parse(data)); const payer = Keypair.fromSecretKey(secretKey); console.log("Payer's public key:", payer.publicKey.toBase58());Creating and Minting SPL Tokensimport { createMint, getMint, mintTo, getOrCreateAssociatedTokenAccount } from '@solana/spl-token'; const token1 = await createMint(connection, payer, payer.publicKey, null, 9); const token2 = await createMint(connection, payer, payer.publicKey, null, 9); const token1Account = await getOrCreateAssociatedTokenAccount(connection, payer, token1, payer.publicKey); const token2Account = await getOrCreateAssociatedTokenAccount(connection, payer, token2, payer.publicKey); await mintTo(connection, payer, token1, token1Account.address, payer.publicKey, 1000000000); // 1000 tokens await mintTo(connection, payer, token2, token2Account.address, payer.publicKey, 1000000000); console.log("Minted tokens and created associated token accounts.");Creating a Liquidity Pool on Raydium:import { Liquidity, DEVNET_PROGRAM_ID, TxVersion, BN } from '@raydium-io/raydium-sdk'; const targetMarketId = Keypair.generate().publicKey; const startTime = Math.floor(Date.now() / 1000) + 60 * 60 * 24 * 7; const walletAccount = await getWalletTokenAccount(connection, payer.publicKey); const createPoolTx = await Liquidity.makeCreatePoolV4InstructionV2Simple({ connection, programId: DEVNET_PROGRAM_ID.AmmV4, marketInfo: { marketId: targetMarketId, programId: DEVNET_PROGRAM_ID.OPENBOOK_MARKET, }, baseMintInfo: { mint: token1, decimals: 9 }, quoteMintInfo: { mint: new PublicKey('So11111111111111111111111111111111111111112'), decimals: 9 }, baseAmount: new BN(10000), quoteAmount: new BN(10000), startTime: new BN(Math.floor(startTime)), ownerInfo: { feePayer: payer.publicKey, wallet: payer.publicKey, tokenAccounts: walletAccount, useSOLBalance: true, }, associatedOnly: false, checkCreateATAOwner: true, makeTxVersion: TxVersion.V0, }); console.log("Liquidity pool created on Raydium.");Add Liquidity:const addLiquidityTx = await Liquidity.makeAddLiquidityInstructionSimple({ connection, poolKeys, userKeys: { owner: payer.publicKey, payer: payer.publicKey, tokenAccounts: walletAccount, }, amountInA: new TokenAmount(new Token(TOKEN_PROGRAM_ID, token1, 9, 'Token1', 'Token1'), 100), amountInB: maxAnotherAmount, fixedSide: 'a', makeTxVersion, }); console.log("Liquidity added to the pool.");Perform a Swap: const swapInstruction = await Liquidity.makeSwapInstruction({ poolKeys, userKeys: { owner: payer.publicKey, tokenAccountIn: fromTokenAccount, tokenAccountOut: toTokenAccount, }, amountIn, amountOut: minimumAmountOut, fixedSide: "in", }); // Correcting the transaction creation by accessing the correct innerTransaction const transaction = new Transaction().add(...swapInstruction.innerTransaction.instructions); const transactionSignature = await connection.sendTransaction( transaction, [payer], { skipPreflight: false, preflightCommitment: "confirmed" } ); console.log("Swap transaction signature:", transactionSignature);Also, Explore | How to Get the Transaction Logs on SolanaConclusionYou have successfully included Raydium's swap feature into your Solana program by following the instructions provided in this Blog. In the DeFi space, Raydium offers strong tools for swapping and liquidity. If you want to leverage the potential of Solana and Raydium Swap Functionality for your project, connect with our skilled Solana developers to get started.

Technology: SMART CONTRACT , POSTGRESQL more Category: Blockchain Development & Web3 Solutions

Rahul Maurya

02 Oct 2024

How to Build a Multi-Chain Account Abstraction Wallet Understanding Account AbstractionAfter Vitalik presented the idea of account abstraction in 2015, it gained attention. The word "account abstraction" is wide, but to put it briefly, it refers to the abstraction of the inflexibility and inherent structure of user accounts in a blockchain. This allows for network interaction while also increasing their flexibility and adaptability. Instead of relying on the pre-built standard Blockchain rules, suppliers of crypto wallet solutions develop user-friendly accounts with unique logic that allows them to apply their own asset storage and transaction conditions.This lets the wallet control user actions without requiring users to sign transactions or physically hold private keys. Wallet development teams create smart contracts that function as user accounts in these kinds of applications. These contracts have the ability to communicate across programs, work with several accounts, and apply unique logic.Multi-Chain Support: Bridging or cross-chain communication protocols can be used as a way to communicate with several blockchains.Smart Contract Architecture: A primary contract and perhaps a factory for generating wallet instances will make up the wallet.Also, Read | ERC 4337 : Account Abstraction for Ethereum Smart Contract WalletsHow to Build a Multi-Chain Account Abstraction WalletStep1: Recognise the Complexities of Account AbstractionUnderstanding the ins and outs of account abstraction is crucial before starting the Account Abstraction wallet process. This is the process of providing user-friendly designs while severing the connection between user accounts and Blockchain accounts.Step:2 Choose an Appropriate Blockchain PlatformChoose a blockchain platform that either supports it natively or can be improved to do so. As an alternative, you may think about Ethereum, which comes with a tonne of Ethereum Improvement Proposals, including ERC-4337, a common AA idea.Step:3 Establish a Development EnvironmentInstall the necessary development tools, such as Hardhat, Truffle, and Node.js, to create smart contracts. Additionally, the establishment of a blockchain node can be done with Ganache or by connecting it to a testnet, like Rinkeby or Ropsten.Step:4 Make the contracts for smart contractsMake a smart contract that shows which user account is in charge of managing transaction volume and user authentication. It is also advisable to have a central point contract that facilitates communication with account contracts. Utilise proxy patterns to incorporate security measures for contract upgrades.Step:5 DesignAim for straightforward, user-friendly designs while considering the diverse user bases. Success results from keeping people interested in the wallet. The design is shared for approval when it has been created.Step:6 Security Audits and TestingThe smart contracts will undergo extensive testing following the development of the solution. Testing is done in various settings to check for mistakes and defects. For smart contract assessments, vulnerability detection, and remediation, third-party auditors are hired.Step:7 Install on the MainnetThe system is ready for post-launch post-testing and Mainnet security assessments. This stage involves configuring the server environment and deploying the code into the production environment.Step:8 Upkeep and ModificationsExamine the systems for problems, and where necessary, apply upgrades. Assist users who may have queries or encounter problems when using the wallet. As a result, the solution will become reliable and capable over time.Step:9 Marketing & Getting User FeedbackTo attract consumers' attention, the solution is advertised through various means. This covers joint ventures and collaborations, recommendations, social media marketing, and YouTube advertising. The solution is improved by the collection of user input.Also, Check | How to Build a Cryptocurrency Wallet App Like ExodusBuilding a Multi-Chain Account Abstraction WalletExample: - Set Up Hardhat:-If you haven't set up a Hardhat project yet, you can do so with the following commands:mkdir MultiChainWallet cd MultiChainWallet npm init -y npm install --save-dev hardhat npx hardhatAdd the ContractCreate a file named MultiChainWallet.sol in the contracts directory and paste the contract code:// SPDX-License-Identifier: MIT pragma solidity ^0.8.0; interface IERC20 { function transfer(address recipient, uint256 amount) external returns (bool); function transferFrom(address sender, address recipient, uint256 amount) external returns (bool); function balanceOf(address account) external view returns (uint256); } contract MultiChainWallet { mapping(address => mapping(address => uint256)) private balances; mapping(address => bool) private wallets; event WalletCreated(address indexed owner); event Deposit(address indexed user, address indexed token, uint256 amount); event Withdraw(address indexed user, address indexed token, uint256 amount); modifier onlyWallet() { require(wallets[msg.sender], "Wallet does not exist"); _; } function createWallet() external { require(!wallets[msg.sender], "Wallet already exists"); wallets[msg.sender] = true; emit WalletCreated(msg.sender); } function deposit(address token, uint256 amount) external onlyWallet { require(amount > 0, "Invalid amount"); IERC20(token).transferFrom(msg.sender, address(this), amount); balances[msg.sender][token] += amount; emit Deposit(msg.sender, token, amount); } function withdraw(address token, uint256 amount) external onlyWallet { require(balances[msg.sender][token] >= amount, "Insufficient balance"); balances[msg.sender][token] -= amount; IERC20(token).transfer(msg.sender, amount); emit Withdraw(msg.sender, token, amount); } function getBalance(address token) external view onlyWallet returns (uint256) { return balances[msg.sender][token]; } } contract MockERC20 is IERC20 { string public name; string public symbol; uint8 public decimals = 18; mapping(address => uint256) private _balances; mapping(address => mapping(address => uint256)) private _allowances; constructor(string memory _name, string memory _symbol, address initialAccount, uint256 initialBalance) { name = _name; symbol = _symbol; _balances[initialAccount] = initialBalance; } function transfer(address recipient, uint256 amount) external override returns (bool) { _transfer(msg.sender, recipient, amount); return true; } function transferFrom(address sender, address recipient, uint256 amount) external override returns (bool) { require(amount <= _allowances[sender][msg.sender], "Allowance exceeded"); _approve(sender, msg.sender, _allowances[sender][msg.sender] - amount); _transfer(sender, recipient, amount); return true; } function balanceOf(address account) external view override returns (uint256) { return _balances[account]; } function approve(address spender, uint256 amount) external returns (bool) { _approve(msg.sender, spender, amount); return true; } function allowance(address owner, address spender) external view returns (uint256) { return _allowances[owner][spender]; } function _transfer(address sender, address recipient, uint256 amount) internal { require(sender != address(0), "Transfer from the zero address"); require(recipient != address(0), "Transfer to the zero address"); require(_balances[sender] >= amount, "Insufficient balance"); _balances[sender] -= amount; _balances[recipient] += amount; } function _approve(address owner, address spender, uint256 amount) internal { require(owner != address(0), "Approve from the zero address"); require(spender != address(0), "Approve to the zero address"); _allowances[owner][spender] = amount; } } You may also like | What is the Cost of Creating a Crypto Wallet App in 2024Create the Deployment Script:Create a new file named deploy.js in the scripts directory and add the following code:// scripts/deploy.jsasync function main() { const MockERC20 = await ethers.getContractFactory("MockERC20"); const mockToken = await MockERC20.deploy("Mock Token", "MTK", "0xYourAddressHere", ethers.utils.parseEther("1000")); await mockToken.deployed(); console.log("MockERC20 deployed to:", mockToken.address); } // Execute the script main() .then(() => process.exit(0)) .catch((error) => { console.error(error); process.exit(1); }); Configure Hardhat NetworkEdit the hardhat.config.js file to configure the network you want to deploy to (for example, the Rinkeby testnet or the local Hardhat network):require('@nomiclabs/hardhat-waffle'); module.exports = { solidity: "0.8.0", networks: { rinkeby: { url: 'https://rinkeby.infura.io/v3/YOUR_INFURA_PROJECT_ID', accounts: [`0x${YOUR_PRIVATE_KEY}`] } } }; Create the Test File Create a new file named MultiChainWallet.test.js in the test directory and add the following test cases:// test/MultiChainWallet.test.js// test/MockERC20.test.jsconst { expect } = require("chai"); const { ethers } = require("hardhat"); describe("MockERC20", function () { let mockToken; let owner; let addr1; let addr2; beforeEach(async function () { const MockERC20 = await ethers.getContractFactory("MockERC20"); [owner, addr1, addr2] = await ethers.getSigners(); mockToken = await MockERC20.deploy("Mock Token", "MTK", owner.address, ethers.utils.parseEther("1000")); await mockToken.deployed(); }); describe("Deployment", function () { it("Should set the correct name and symbol", async function () { expect(await mockToken.name()).to.equal("Mock Token"); expect(await mockToken.symbol()).to.equal("MTK"); }); it("Should assign the initial balance", async function () { const balance = await mockToken.balanceOf(owner.address); expect(balance).to.equal(ethers.utils.parseEther("1000")); }); }); describe("Transactions", function () { it("Should transfer tokens between accounts", async function () { await mockToken.transfer(addr1.address, ethers.utils.parseEther("100")); const addr1Balance = await mockToken.balanceOf(addr1.address); expect(addr1Balance).to.equal(ethers.utils.parseEther("100")); }); it("Should approve tokens for spending", async function () { await mockToken.approve(addr1.address, ethers.utils.parseEther("50")); const allowance = await mockToken.allowance(owner.address, addr1.address); expect(allowance).to.equal(ethers.utils.parseEther("50")); }); it("Should transfer tokens from one account to another", async function () { await mockToken.approve(addr1.address, ethers.utils.parseEther("50")); await mockToken.connect(addr1).transferFrom(owner.address, addr2.address, ethers.utils.parseEther("50")); const addr2Balance = await mockToken.balanceOf(addr2.address); expect(addr2Balance).to.equal(ethers.utils.parseEther("50")); }); }); });Also, Read | How to Build a Real-Time Wallet TrackerDeploy the ContractTo deploy the contract, run the following command in your terminal:npx hardhat run scripts/deploy.js --network <network_name>Verify the Deployment:-Once deployed, you should see the contract address in the terminal output. You can verify the deployment on Etherscan (for public networks) or through your local Hardhat node.Overview of the Above Contract:-Deposit Function: The wallet allows users to deposit Ether, with the balance being linked to a particular chain ID.Withdraw Function: Users are able to take their remaining Ether balance for a certain chain out. Execute Function: Using a signature-based verification system, this function enables the owner to carry out transactions on other contracts.Events: For tracking purposes, send out events for deposits, withdrawals, and completed transactions.Explanation of the TestsDeposit Tests: Tests that users can deposit Ether and that their balance is updated accordingly. Checks that the Deposited event is emitted.Withdraw Tests: Ensures that users can withdraw their Ether. Validates that trying to withdraw more than the balance reverts the transaction. Checks that the Withdrawn event is emitted.Execute Tests: Validates that the owner can successfully execute a transaction. Tests that an invalid signature reverts the transaction.Interactions Across Chains: Cross-chain interactions are not specifically handled by this contract. You could utilise bridging mechanisms like Wormhole or LayerZero, oracles, to establish communication between various chains in order to do this.Security: Whenever you work with different chains, make sure to audit your contracts and take into account possible attack routes.Gas Efficiency: When building your functions, especially for cross-chain calls, keep gas expenses in mind.Also, Check | Create an Externally Owned Wallet using Web3J and Spring BootTesting and Deployment:-You can utilise test networks for the individual chains you wish to support together with frameworks like Hardhat or Truffle to deploy and test this contract.Boost Functionality: Include extra features such as role-based access control, support for ERC20 tokens, and recovery methods.Cross-Chain Communication: To move assets between chains, investigate and put into practice cross-chain protocols.User Interface: Using Web3.js or Ethers.js frameworks, create a front-end interface for interacting with the wallet. This ought to provide you with a basic idea of how to construct a Solidity wallet that abstracts multiple chains of accounts. Be sure to modify and enlarge the code in accordance with the specifications of your project!Monetary Benefits of Investing in Account Abstraction Wallet:-Cost is a significant component of Account Abstraction wallet development. It is impacted by numerous factors that bring these apps to life. Let us spotlight these factors in detail:Development Team SizeThe expertise and experience of the development team affect the wallet cost. Hire a skilled team with Blockchain background and consider the cost of developers, designers, blockchain experts and security professionals.Features and ComplexityThe features integrated within the application have a direct influence on the cost. The charges of basic wallets are less, while the advanced ones escalate the cost.Security MeasuresThe significance of powerful security mechanisms can't be understated. The higher the security, the higher the development charges. Make sure that the advanced security mechanisms are integrated, which is a significant investment but gives you peace of mind.Legal and Compliance CostsAddressing complaint measures involves legal consultations and ensuring that the application adheres to local and global regulations. These costs are included in the overall budget.Also, Discover | How to Sign Ledger using Solana Wallet AdapterAccount Abstraction Wallets DrawbacksComplexity: Compared to standard wallets, the architecture may be more intricate, which might increase the likelihood of errors or implementation flaws.Experience of the User: Those who are only familiar with conventional wallets may find it difficult to grasp new ideas like transaction signature off-chain.Difficulties with Onboarding: It might be difficult for novice users to set up and use these wallets efficiently.Smart Contract Weaknesses: The usage of smart contracts exposes users to more risks, including those related to reentrancy attacks, vulnerabilities, and exploits that might result in financial loss.Signature Management: Insecure implementation of off-chain signing techniques may result in compromised private keys.Reliance on Oracles and Bridges: Multi-chain functionality often depends on external oracles and bridging services, which can introduce additional points of failure.Potential Latency: Cross-chain transactions might be slower due to the need for confirmations and interactions with multiple networks.KYC/AML Concerns: Implementing features like KYC for account abstraction wallets could complicate user privacy and lead to regulatory scrutiny.Compliance Complexity: Ensuring compliance across multiple jurisdictions can be challenging and resource-intensive.Interoperability Challenges: Different chains may have varying standards and functionalities, complicating interoperability and the overall user experience.Limited Support: Not all decentralized applications (dApps) may support account abstraction wallets, limiting their usability.If you are looking for assistance to build your blockchain-based project, connect with our skilled blockchain developers to get started.

Technology: SMART CONTRACT , REDIS more Category: Blockchain Development & Web3 Solutions

Kapil Dagar

01 Oct 2024

ERC 4337 : Account Abstraction for Ethereum Smart Contract Wallets Understanding Account Abstraction on Ethereum for Smart Contract WalletsA novel concept in blockchain, account abstraction aims to improve and harmonize user account functionality in decentralized systems. Contract wallets, also known as smart contract accounts, can replace traditional externally held accounts thanks to account abstraction and smart contract development. A contract wallet can be controlled by a single key, multiple keys, or even a complex system encoded into the contract itself. This opens up numerous possibilities and benefits for Ethereum and other blockchain networks. Account abstraction allows for more flexible and secure management of contract wallets compared to traditional externally held accounts. For more about blockchain, Ethereum, and smart contracts, visit our smart contract development services.In the Ethereum network, two types of accounts currently exist:Externally Owned Accounts (EOAs): controlled by private keys and typically of specific people or organizations.Contract Accounts: smart contracts whose code is run according to predetermined logic.Account abstraction seeks to unify the two types of Ethereum accounts:This implies that smart contracts can now manage and carry out transactions on behalf of users rather than exclusively depending on private keys (as with EOAs), providing users with more flexibility and opening the door to new features like customizable security models, automated and gasless transactions, meta-transactions, and improved privacy. These developments streamline user interactions and increase the Ethereum ecosystem's potential.Also, Read | How to Create an NFT Rental Marketplace using ERC 4907Why do we need Account Abstraction ?The current configuration of the Ethereum network has several drawbacks:Security Risks: Due to their binary structure, private keys can be lost or stolen, which can result in an irreversible loss of money.User Experience: For new users who could find wallet security and gas principles confusing, EOAs demand private keys and gas costs in Ether, which causes friction.Hazards to Security: Due to their binary structure, private keys can be lost or stolen, which can result in an irreversible loss of money.Limited Features: Advanced features like multi-signature wallets and daily transaction restrictions cannot be implemented on EOAs due to their lack of programmability.By addressing these problems, account abstraction seeks to enhance the functionality, security, and usability of the network.Also, Read | A Guide to Implementing NFT Royalties on ERC-721 & ERC-1155Approaches to Implement Account Abstraction:Protocol-Level ChangesIt entails modifying the Ethereum protocol to allow native wallets for smart contracts. Consensus is required for this strategy throughout the Ethereum network.Layer 2 SolutionsLayer 2 networks provide the ability to offload transaction processing and implement unique transaction validation procedures.ERC 4337 (Ethereum Request for Comments)It suggests implementing account abstraction just at the application level, eliminating the need for protocol modifications.Also, Read | How to Create and Deploy a Token Bound Account | ERC-6551What is ERC 4337?A new transaction handling mechanism called UserOperation objects is introduced in ERC 4337. By signing UserOperation objects, which bundlers aggregate and transmit to the network, users avoid submitting transactions straight to the Ethereum blockchain. Without relying on the current transaction flow, this method enables smart contract wallets to safely start transactions. Implementation of ERC 4337:A number of essential elements are involved in the Solidity implementation of ERC 4337 (Account Abstraction), which combined allow for flexible and intuitive interactions with smart contracts. These are the primary elements to pay attention to:1. UserOperation StructPurpose: Represents a single user operation with all necessary information.Key Fields:sender: The address of the user or wallet executing the operation.nonce: To prevent replay attacks and track the order of operations.callData: The encoded data for the function call.gasLimit: The maximum amount of gas that can be used for the operation.maxFeePerGas & maxPriorityFeePerGas: Control over gas fees.You may also like | How to Create an ERC 721C Contract// SPDX-License-Identifier: MIT pragma solidity ^0.8.0; contract UserOperationExample { struct UserOperation { address sender; // Address of the user sending the operation uint256 nonce; // Unique nonce to prevent replay attacks bytes callData; // Encoded data for the function call uint256 gasLimit; // Maximum gas limit for the operation uint256 maxFeePerGas; // Maximum fee per gas unit the user is willing to pay uint256 maxPriorityFeePerGas; // Max priority fee per gas } // Example function to demonstrate the use of UserOperation function exampleFunction(UserOperation calldata userOp) external { // Validate the user operation (you would typically check nonce, gas limits, etc.) require(userOp.sender != address(0), "Invalid sender"); require(userOp.gasLimit > 0, "Gas limit must be greater than zero"); // Here you would implement the logic to execute the operation (bool success, ) = userOp.sender.call{gas: userOp.gasLimit}(userOp.callData); require(success, "Operation failed"); // You could also emit an event here for tracking purposes } }Also, Discover | How to Create and Deploy an ERC404 token contract2. EntryPoint ContractPurpose: Central contract that receives user operations and executes them.Key Functions:executeUserOperation: Validates and executes the user operation, checking the sender's nonce, ensuring gas limits, and processing the call data.Security Checks: Implement checks to prevent issues like underflow/overflow, invalid addresses, and ensure gas payment.// SPDX-License-Identifier: MIT pragma solidity ^0.8.0; contract EntryPoint { event UserOperationExecuted(address indexed sender, bytes callData); event UserOperationFailed(address indexed sender, bytes callData, string reason); // This mapping tracks the nonce for each user to prevent replay attacks mapping(address => uint256) public nonces; function executeUserOperation(UserOperation calldata userOp) external { // Validate the user operation require(userOp.sender != address(0), "Invalid sender"); require(userOp.nonce == nonces[userOp.sender], "Invalid nonce"); require(userOp.gasLimit > 0, "Gas limit must be greater than zero"); // Update the nonce nonces[userOp.sender]++; // Execute the operation (bool success, bytes memory returnData) = userOp.sender.call{gas: userOp.gasLimit}(userOp.callData); if (success) { emit UserOperationExecuted(userOp.sender, userOp.callData); } else { emit UserOperationFailed(userOp.sender, userOp.callData, _getRevertMsg(returnData)); } } // Helper function to extract revert reason function _getRevertMsg(bytes memory returnData) internal pure returns (string memory) { if (returnData.length < 68) return "Transaction reverted silently"; assembly { returnData := add(returnData, 0x04) } return abi.decode(returnData, (string)); } }Also, Discover | ERC 3643 A Protocol for Real World Asset Tokenization3. User Wallet ContractPurpose: Acts as the user's wallet to create and submit user operations.Key Functions:submitUserOperation: Collects user operation parameters and sends them to the Entry Point.Nonce Management: Increments the nonce after a successful operation to prevent replay attacks. // SPDX-License-Identifier: MIT pragma solidity ^0.8.0; import "./EntryPoint.sol"; // Import the EntryPoint contract contract UserWallet { address public entryPoint; // Address of the EntryPoint contract uint256 public nonce; // Nonce for tracking user operations constructor(address _entryPoint) { entryPoint = _entryPoint; // Set the EntryPoint contract address } // Function to submit a user operation function submitUserOperation( bytes calldata callData, uint256 gasLimit, uint256 maxFeePerGas, uint256 maxPriorityFeePerGas ) external { // Create the UserOperation struct UserOperation memory userOp = UserOperation({ sender: address(this), nonce: nonce, callData: callData, gasLimit: gasLimit, maxFeePerGas: maxFeePerGas, maxPriorityFeePerGas: maxPriorityFeePerGas }); // Submit the user operation to the Entry Point EntryPoint(entryPoint).executeUserOperation(userOp); // Increment the nonce for the next operation nonce++; } // Example function to demonstrate a callable function from the wallet function exampleFunction(uint256 value) external { // Implementation of the function logic } }Also, Check | A Guide to Gasless ERC20 Token Transfer4. Gas Payment MechanismPurpose: Determines how the gas for executing user operations is paid.Considerations:You might want to allow users to pay gas fees in tokens or implement a mechanism for sponsor payments (where another entity pays the gas). // SPDX-License-Identifier: MIT pragma solidity ^0.8.0; import "@openzeppelin/contracts/token/ERC20/IERC20.sol"; contract EntryPoint { event UserOperationExecuted(address indexed sender, bytes callData); event UserOperationFailed(address indexed sender, bytes callData, string reason); mapping(address => uint256) public nonces; // Function to execute user operation with gas payment function executeUserOperation( UserOperation calldata userOp, address paymentToken, uint256 paymentAmount ) external payable { require(userOp.sender != address(0), "Invalid sender"); require(userOp.nonce == nonces[userOp.sender], "Invalid nonce"); require(userOp.gasLimit > 0, "Gas limit must be greater than zero"); // Validate gas payment if (paymentToken == address(0)) { // Pay with Ether require(msg.value >= paymentAmount, "Insufficient Ether sent"); } else { // Pay with ERC-20 token require(IERC20(paymentToken).transferFrom(msg.sender, address(this), paymentAmount), "Token transfer failed"); } nonces[userOp.sender]++; (bool success, bytes memory returnData) = userOp.sender.call{gas: userOp.gasLimit}(userOp.callData); if (success) { emit UserOperationExecuted(userOp.sender, userOp.callData); } else { emit UserOperationFailed(userOp.sender, userOp.callData, _getRevertMsg(returnData)); } } function _getRevertMsg(bytes memory returnData) internal pure returns (string memory) { if (returnData.length < 68) return "Transaction reverted silently"; assembly { returnData := add(returnData, 0x04) } return abi.decode(returnData, (string)); } }5. Account Abstraction WalletPurpose:To manage user actions, an Entry Point contract communicates with the Abstracted Account Wallet, which functions as a user-defined wallet. By offering a means of verifying and carrying out these procedures, it guarantees that activities may only be carried out by authorized users. // SPDX-License-Identifier: UNLICENSED pragma solidity ^0.8.9; import "./library/UserOperation.sol"; import "@openzeppelin/contracts/utils/cryptography/ECDSA.sol"; contract AbstractedAccountWallet { using ECDSA for bytes32; uint256 public constant SIG_VALIDATION_FAILED = 1; uint256 public constant NONCE_VALIDATION_FAILED = 2; uint256 public constant VALIDATION_SUCCESS = 0; address public owner; uint256 public nonce; address public entryPoint; // Events for logging important actions event ExecutedOperation(address indexed sender, uint256 value, bytes data); constructor(address _entryPoint) { owner = msg.sender; nonce = 0; entryPoint = _entryPoint; } // Modifier to check if the caller is the owner of the contract modifier onlyOwner() { require(msg.sender == owner, "You are not the owner"); _; } modifier onlyEntryPoint() { require( msg.sender == entryPoint, "Only EntryPoint can call this function" ); _; } // Function to validate a user-defined operation function validateOp( UserOperation calldata op, uint256 requiredPayment ) public returns (uint256) { // Send requiredPayment to EntryPoint if (requiredPayment != 0) { payable(entryPoint).transfer(requiredPayment); } // Check nonce require(op.nonce == nonce++, "Invalid nonce"); // Check signature if ( owner != getHash(op).toEthSignedMessageHash().recover( // op.signature[32:] op.signature ) ) { return SIG_VALIDATION_FAILED; } else { // return uint256(bytes32(op.signature[0:32])); return VALIDATION_SUCCESS; } } function getHash( UserOperation memory userOp ) public view returns (bytes32) { return keccak256( abi.encode( bytes32(block.chainid), userOp.sender, userOp.nonce, keccak256(userOp.initCode), keccak256(userOp.callData), userOp.callGasLimit, userOp.verificationGasLimit, userOp.preVerificationGas, userOp.maxFeePerGas, userOp.maxPriorityFeePerGas, keccak256(userOp.paymasterAndData), entryPoint // uint256(bytes32(userOp.signature[0:32])) ) ); } }You may also like | How to Create an ERC 721 NFT TokenA recent breakthrough: EIP-4337Since the account abstraction effort moved to a different strategy, which was unveiled in EIP-4337 in late 2021, both EIP-2938 and EIP-3074 are presently dormant. Building on the idea of a smart contract wallet is the goal of the new strategy.However, remember that we already mentioned that the lack of proper infrastructure makes smart contract wallets challenging to use? Nevertheless, EIP-4337 seeks to address that without altering the L1 protocol in the process.The proposal introduces a higher-level mempool that operates with a new object called UserOperations. Instead of traditional transactions, users will send UserOperations to this mempool. Validators then select these UserOperations, bundle them into a transaction, and submit them to a specialized smart contract called the EntryPoint contract. This contract manages transaction execution and validator rewards.The method outlined in EIP-4337 simplifies the process for developers to create custom smart contract wallets.Also, Know | Create a Simple Dividend ERC20 tokenConclusion of Account Abstraction Using ERC 4337:Account abstraction and ERC 4337 are two progressive approaches to Ethereum's development. This strategy is well-positioned to promote the wider use of blockchain technology and decentralised apps by giving priority to user experience, flexibility, and security, so making them more accessible and useful for regular users. The ideas and applications resulting from ERC 4337 will probably influence the direction of decentralised finance in the future and beyond as the ecosystem develops. In case you are looking to build your project using emerging ERC standards, connect without our skilled Solidity developers to get started.

Technology: SMART CONTRACT , ETHERJS more Category: Blockchain Development & Web3 Solutions

Yogesh Sahu

01 Oct 2024

How to Build a Cross-Chain Bridge Using Solidity and Rust The capacity to transfer assets across networks effortlessly is more important than ever in the ever-changing world of blockchain development. Envision a bridge that unites the Ethereum and Solana worlds, letting tokens move freely while upholding security and openness. In this project, we use the robust programming languages Solidity and Rust to set out on the task of creating a cross-chain bridge. Through utilizing Rust's efficiency for Solana's on-chain logic and Solidity's capabilities for Ethereum smart contracts, our goal is to provide a solid framework that makes token exchanges simple. Whether you're a crypto enthusiast excited to explore new possibilities or a developer trying to improve interoperability, this guide will take you through all the necessary steps to realize this ambitious aim. Now let's dive in.PrerequisitesProgrammingLanguages:Solidity, Javascript/Typescript, and RustIDE:VS-Code and any preferred IDELibraries:ETH:Hardhat, Ethers, Axios, OpenzepplinSOL:Solana Web3.js, Solana Spl-tokenAlso, Explore | How To Build "Buy Me a Coffee" DeFi dApp Using SolidityHow to Build a Cross-Chain Bridge Using Solidity and RustIt's preferred that you setup 3 projects, separately for:I) Ethereum's ERC-20 Token Smart Contract:You'll need to setup node.js, solidity and hardhat in your IDE/ system. So, we'll begin with setting up hardhat code, for example "click-here". Here's the code for the ERC-20 Token using Openzepplin's library.code.................................................................................................. // SPDX-License-Identifier: MIT pragma solidity ^0.8.0; import "@openzeppelin/contracts/token/ERC20/ERC20.sol"; import "@openzeppelin/contracts/access/Ownable.sol"; contract Testtoken is ERC20, Ownable { event BurnAndMoveToSolana(address indexed user, string solanaAddress, uint256 amount); event MintFromSolana(address indexed user, uint256 amount); address public relayer; constructor() ERC20("EthereumToken", "ETHR") Ownable(msg.sender){ _mint(msg.sender, 1000000 * (10 ** decimals()));// change amount as per your understanding } modifier onlyRelayer() { require(msg.sender == relayer, "Not authorized"); _; } function setRelayer(address _relayer) external onlyOwner { relayer = _relayer; } function burnAndMoveToSolana(uint256 amount, string memory solanaAddress) external {// main transfering function _burn(msg.sender, amount); emit BurnAndMoveToSolana(msg.sender, solanaAddress, amount); } function mintFromSolana(address to, uint256 amount) external onlyRelayer { _mint(to, amount); emit MintFromSolana(to, amount); } event TokensBurned(address indexed from, address indexed solanaAddress, uint256 amount); }You may also like | Building a Decentralized Voting System with Solidity and Hardhat2) Solana's SPL Token Program:You'll need to setup node.js, Solana, and Rust in your IDE/ system. To begin with, we'll set-up a empty solana-sdk code. Here's the full code/implementation for the SPL Token using Solana-web3.js & Solana spl-token.code................................................................................................. const { Connection, Keypair, PublicKey, clusterApiUrl, LAMPORTS_PER_SOL } = require('@solana/web3.js'); const { createMint, getOrCreateAssociatedTokenAccount, mintTo, getAccount, burn } = require('@solana/spl-token'); async function mintAndBurnTokens(connection, fromWallet, tokenAccount, mint, amountToMint, amountToBurn, ethAddress) { await mintTo( connection, fromWallet, mint, tokenAccount.address, fromWallet.publicKey, amountToMint ); console.log(`Minted ${amountToMint / (10 ** 9)} tokens to your associated token account.`); const tokenAccountBalance = await getAccount(connection, tokenAccount.address); console.log(`Token account balance after minting: ${Number(tokenAccountBalance.amount) / (10 ** 9)} tokens`); if (Number(tokenAccountBalance.amount) < amountToBurn) { console.log(`Insufficient funds. Current balance: ${Number(tokenAccountBalance.amount) / (10 ** 9)} tokens.`); return; } await burn( connection, fromWallet, tokenAccount.address, mint, fromWallet.publicKey, amountToBurn ); console.log(`Burned ${amountToBurn / (10 ** 9)} tokens from ${fromWallet.publicKey} and moving to Ethereum wallet ${ethAddress}.`); console.log(`Relaying burn event to Ethereum relayer for Ethereum wallet: ${ethAddress}, amount: ${amountToBurn / (10 ** 9)}.`); } (async () => { const fromWallet = Keypair.fromSecretKey(new Uint8Array([your,secret,keypair])); const ethAddress = "0xyourAddress";//add your eth wallet address const mintAmount = 100000 * 10 ** 9;// amount of SPL tokens to mint const burnAmount = 1000 * 10 ** 9;// amount of SPL tokens to burn/transfer const connection = new Connection(clusterApiUrl('devnet'), 'confirmed');// put your preferred cluster console.log('Creating SPL token...'); const mint = await createMint( connection, fromWallet, fromWallet.publicKey, null, 9 ); const fromTokenAccount = await getOrCreateAssociatedTokenAccount( connection, fromWallet, mint, fromWallet.publicKey ); console.log('Minting tokens...'); await mintAndBurnTokens(connection, fromWallet, fromTokenAccount, mint, mintAmount, burnAmount, ethAddress); console.log(`View token account on Solana Explorer: https://explorer.solana.com/address/${fromTokenAccount.address}?cluster=devnet`); })(); ////////////////////////////////////////////////////////////////////////Also, Read | How To Create a Daily Game Reward System in Solidity3) Relayer-Bridge Project:In order to facilitate safe and transparent token transfers between two blockchains, a relayer-bridge project serves as an essential bridge. Using smart contracts and event listeners, the relayer in the Ethereum and Solana context watches on particular occurrences on one blockchain, like an Ethereum token burn. When the relayer notices one of these events, it sends the required information—such as the recipient's address and the quantity of tokens—to the other chain so that the corresponding action—like minting the tokens on Solana—can take place there. In order to preserve network balance, this bi-directional communication makes sure that tokens burned on one chain are minted on the other. In order to smoothly connect the two ecosystems, the relayer's job is to validate and relay these transactions without sacrificing security or speed.Here's the Code for the Relayer-Bridge :code.................................................................................................. const WebSocket = require("ws"); const { ethers } = require("ethers"); const fs = require("fs"); require('dotenv').config(); const wsUrl = "wss://api.devnet.solana.com";//your desired network const connection = new WebSocket(wsUrl); const provider = new ethers.WebSocketProvider(process.env.ETH_WSS_URL); const wallet = new ethers.Wallet(process.env.ETH_PRIVATE_KEY, provider); const contractAddress = process.env.ETH_CONTRACT_ADDRESS; const abi = JSON.parse(fs.readFileSync("./path_to_your/eth_contract_abi.json")); const contract = new ethers.Contract(contractAddress, abi, wallet); connection.on("open", () => { console.log("Connected to Solana WebSocket"); const subscriptionMessage = JSON.stringify({ jsonrpc: "2.0", id: 1, method: "logsSubscribe", params: [ { mentions: [""],// Your SPL token address }, { commitment: "finalized", }, ], }); connection.send(subscriptionMessage); }); connection.on("message", async (data) => { const response = JSON.parse(data); if (response.method === "logsNotification") { const logData = response.params.result; // Check if the log indicates a burn if (isBurnLog(logData)) { const amountBurned = extractBurnAmount(logData); console.log(`Burn detected: ${amountBurned} tokens`); await mintTokens(amountBurned); } } else { console.log("Received message:", response); } }); connection.on("close", () => { console.log("Connection closed"); }); connection.on("error", (error) => { console.error("WebSocket error:", error); }); // Function to Check the log data structure to confirm it's a burn event function isBurnLog(logData) { return logData && logData.err === null && logData.logs && logData.logs.some(log => log.includes("burn")); } // Function to extract the amount burned from the log data function extractBurnAmount(logData) { const amountLog = logData.logs.find(log => log.includes("burn")); if (amountLog) { const amount =/* logic to parse your burn amount format */; return parseFloat(amount);// Return the amount as a number } return 0; } // Function to mint tokens on Ethereum async function mintTokens(amount) { try { const tx = await contract.mint(wallet.address, ethers.utils.parseUnits(amount.toString(), 18)); console.log(`Mint transaction sent: ${tx.hash}`); await tx.wait(); console.log("Minting successful"); } catch (error) { console.error("Minting failed:", error); } } /////////////////////////////////////////////////////////////////////////This part of the relayer works for the transfer of SPL tokens to the ERC-20 tokens on Ethereum. Similarly, we can perform the transfer of ERC-20 tokens to SPL Tokens on the Solana blockchain, burn them, and its functionality will trigger the SPL Token's mint function to complete the cross-chain transaction.Also, Discover | How to Create a MultiSig Wallet in SolidityConclusionIn conclusion, creating a relayer-equipped cross-chain bridge enables users to transfer assets between Ethereum and Solana with ease, opening up a world of decentralised opportunities. Utilising Solidity and Rust's respective advantages, you can build a scalable, secure solution that connects two robust blockchain ecosystems. This project shapes the future of decentralised finance by paving the ground for true blockchain interoperability with the correct tools and knowledge. Connect with our skilled Solidity developers to bring your blockchain-related vision into reality.

Technology: MEAN , PYTHON more Category: Blockchain Development & Web3 Solutions

Ashish Gushain

30 Sep 2024

Building a Custom Blockchain Consensus Mechanism Blockchain technology relies on consensus algorithms to validate transactions and maintain network integrity. While public blockchains use popular algorithms like Proof of Work (PoW) or Proof of Stake (PoS), private blockchains often require a custom consensus mechanism tailored to their specific needs. In this blog, we'll explore how to build a custom consensus algorithm for a private blockchain, ensuring it's secure, efficient, and meets your business requirements. For more about blockchain, visit our blockchain development services.What is a Consensus Algorithm?A consensus algorithm is a mechanism that allows all participants in a blockchain network to agree on the state of the ledger. This agreement ensures that the data in the blockchain is accurate and prevents fraudulent transactions or data tampering.Why Build a Custom Consensus Algorithm for a Private Blockchain?Control: Private blockchains are often used by organizations that want control over who can participate in the network.Efficiency: Custom algorithms can be designed to be more efficient for smaller networks, reducing transaction confirmation times.Security: Tailored algorithms provide an extra layer of security by addressing specific threats relevant to the private blockchain environment.Also, Check | How to Create Your Own Private Blockchain using CosmosChoosing a Suitable Consensus AlgorithmBefore we start building, let's briefly discuss different consensus algorithms that can inspire your custom model:Proof of Authority (PoA):Only trusted nodes can validate transactions, suitable for private networks with a small number of participants.Raft Consensus:A leader-based approach where one node is elected as the leader to manage transactions.Practical Byzantine Fault Tolerance (PBFT):Handles faulty nodes and works efficiently in networks with up to one-third of malicious participants.Also, Explore | How to Utilize Rollup-as-a-Service for Maximum EfficiencyStep-by-Step Guide to Building the Custom Consensus AlgorithmStep 1: Define the Blockchain StructureBlock Class class Block { constructor(index, timestamp, data, previousHash = '') { this.index = index; // Position of the block in the chain this.timestamp = timestamp; // The time when this block was created this.data = data; // Information to be stored in the block (e.g., transactions) this.previousHash = previousHash; // Hash of the previous block in the chain this.hash = this.calculateHash(); // Unique identifier generated for this block this.validator = null; // The validator node that approves this block } delves calculateHash() { return CryptoJS.SHA256( this.index + this.timestamp + JSON.stringify(this.data) + this.previousHash ).toString(); } }Detailed Breakdown:Each block has an index, timestamp, data, previousHash, hash, and validator. The calculateHash() function combines the block's properties and generates a unique hash using the SHA-256 algorithm. This hash ensures that even a small change in the block's data will result in a completely different hash, making the blockchain tamper-resistant.Key Point: In blockchain, the hash acts like a digital fingerprint for each block. It's crucial because it ensures that data within the block hasn't been altered.Also, Read | How ShadCN is better than AndDBlockchain Class class Blockchain { constructor() { this.chain = [this.createGenesisBlock()]; // Initialize the blockchain with the first block this.validators = ['Node1', 'Node2', 'Node3']; // Nodes authorized to validate new blocks } createGenesisBlock() { return new Block(0, '01/01/2024', 'Genesis Block', '0'); // First block with no previous hash } getLatestBlock() { return this.chain[this.chain.length - 1]; // Fetch the last block added to the chain } addBlock(newBlock) { newBlock.previousHash = this.getLatestBlock().hash; // Connect the new block to the previous one newBlock.hash = newBlock.calculateHash(); // Calculate the hash based on the new block's data // Apply the consensus mechanism newBlock.validator = this.selectValidator(); if (this.isBlockValid(newBlock)) { this.chain.push(newBlock); // Add the block to the chain if valid console.log(`Block approved by: ${newBlock.validator}`); } else { console.log('Block rejected'); } } isBlockValid(block) { // Ensure the selected validator is authorized return this.validators.includes(block.validator); } selectValidator() { // Randomly choose a validator to approve the block const selectedValidator = this.validators[Math.floor(Math.random() * this.validators.length)]; return selectedValidator; } isChainValid() { for (let i = 1; i < this.chain.length; i++) { const currentBlock = this.chain[i]; const previousBlock = this.chain[i - 1]; // Check the integrity of the block if (currentBlock.hash !== currentBlock.calculateHash()) return false; // Verify the chain linkage if (currentBlock.previousHash !== previousBlock.hash) return false; } return true; } }Genesis Block:The genesis block is the first block in the blockchain. It's created with index = 0 and has a previousHash of '0' because it doesn't have any predecessor.addBlock(newBlock):The addBlock function adds a new block to the blockchain, ensuring the chain's integrity by setting previousHash to the hash of the latest block.The selectValidator function randomly picks a validator node to approve the block. If approved by an authorized validator, the block is added to the blockchain.selectValidator():The selectValidator function represents the core of our Proof of Authority (PoA) consensus mechanism. Here, validators are chosen at random, but you can enhance this logic based on factors like node reputation or stake.isChainValid():This function verifies the integrity of the entire blockchain. It ensures that each block's hash matches the recalculated hash using calculateHash() and that previousHash correctly links to the preceding block.Important Concept: The blockchain maintains its integrity through these hashes. Any change to a block's data would alter its hash, breaking the chain's continuity and making tampering evident.You may also like | How to Swap Tokens on Uniswap V3Step 2: Testing the BlockchainLet's test our custom blockchain:let myBlockchain = new Blockchain(); myBlockchain.addBlock(new Block(1, '02/01/2024', { amount: 100 })); myBlockchain.addBlock(new Block(2, '03/01/2024', { amount: 200 })); console.log(JSON.stringify(myBlockchain, null, 4)); console.log('Is blockchain valid? ' + myBlockchain.isChainValid());Explanation:We create an instance of Blockchain and add two blocks with transaction data { amount: 100 } and { amount: 200 }.Finally, we print the entire blockchain to see its structure and check its validity using isChainValid().Also, Discover | How to Develop a Layer 1 BlockchainEnhancing the Consensus Mechanism: VotingThe basic algorithm randomly selects a validator to approve a block. For more security, we introduced a voting mechanism where multiple validators decide.Voting Mechanism ExampleaddBlock(newBlock) { newBlock.previousHash = this.getLatestBlock().hash; newBlock.hash = newBlock.calculateHash(); let approvalCount = 0; // Simulate voting by validators this.validators.forEach(validator => { if (Math.random() > 0.4) { console.log(`${validator} approved the block`); approvalCount++; } else { console.log(`${validator} rejected the block`); } }); if (approvalCount >= 2) { this.chain.push(newBlock); console.log(`Block approved with ${approvalCount} votes`); } else { console.log('Block rejected'); } }Detailed Explanation:The block requires approval from at least 2 out of 3 validators. For each validator, there's a 60% chance of approving the block (Math.random() > 0.4). This mechanism ensures that no single validator can make decisions, providing greater security and trust.Also, Read | How to Access Private Data in Smart ContractsReal-World SignificancePrivate Network: In a corporate setting, this custom algorithm ensures that only authorized participants can validate transactions.Security: By implementing a voting mechanism, you reduce the risk of fraudulent activities, as multiple validators must approve each transaction.Scalability: Custom algorithms are optimised for small, private networks, reducing transaction confirmation times compared to public blockchains.Also, Check | How to Fork Ethereum with HardhatConclusionThis detailed explanation covers how to create a custom consensus algorithm tailored to a private blockchain using concepts from the Proof of Authority (PoA) and introduces voting mechanisms. By understanding how validators are selected, how blocks are validated, and how consensus is achieved, you now have a solid foundation for implementing custom blockchain solutions.You can expand this model into a more robust solution by implementing advanced features like reputation tracking, penalty mechanisms for dishonest nodes, or integrating cryptographic signatures for additional security.By experimenting with this code, you'll gain practical experience and develop a deeper understanding of consensus algorithms, preparing you for more advanced blockchain projects. Feel free to modify and experiment with the code to match your specific requirements!Key TakeawaysUnderstand your network's needs: Tailor your algorithm for efficiency, security, and control.Customize validation logic: Implement mechanisms like voting or reputation to enhance the consensus process.Experiment and iterate: Continuously test and refine your algorithm to achieve optimal performance.This blog should help you understand how to build a custom consensus algorithm and implement it in a private blockchain. Feel free to modify and enhance the code to suit your specific requirements. In case if you are looking for blockchain development services, connect with our skilled blockchain developers to get started.

Technology: MEAN , PYTHON more Category: Blockchain Development & Web3 Solutions

Ashutosh Modanwal

28 Sep 2024

How to Create an NFT Rental Marketplace using ERC 4907 NFT Rental Marketplace Development using ERC 4907For a predetermined period, NFT owners can lease their tokens to third parties via ERC 4907. This functionality allows different players or users to temporarily use the NFTs in various applications, such as virtual real estate or gaming.The roles involved in this process include the Owner, who possesses the NFT; the User, who has the NFT in their wallet but is unable to sell or transfer it; and the "expires" function, which automatically ends usage without any further action required.A controller or operator role is assigned to oversee a large number of NFTs. While they can perform certain usage operations, individuals in these roles are unable to approve or transfer the NFT, unlike the owner.As an extension of ERC-721, the ERC 4907 standard introduces the dual roles of "owner" and "user" at the application layer. With an automatic "expires" mechanism that enforces the user's time-limited role, ERC 4907 simplifies NFT rentals. Thanks to this innovative feature, NFTs are automatically rentable; owners no longer need to manually revoke user privileges, saving time and avoiding additional on-chain transactions.The main challenge arises in usage rights management, making it essential to establish a unified standard to facilitate collaboration across all applications.You may also like | Why ERC-7007 is the Next Big Thing in BlockchainReal-world Applications and CollaborationsIt's becoming more and more common in the world of digital assets for non-fungible tokens (NFTs) to use the new Ethereum token standard, ERC 4907. In order to facilitate the temporary transfer of usage rights while maintaining ownership, it creates a new "user role" that is distinct from the "owner role." This is advantageous for subscription or rental models.In order to enable NFT rentals, Double Protocol has incorporated ERC 4907, allowing asset owners to lease without forfeiting ownership. This expands the utility of NFT and opens up new revenue streams. By including ERC 4907-based rental options, their relationship with Shardeum, a scalable smart contract platform, improves this strategy even further and fosters an NFT ecosystem that is more widely available.These collaborations highlight the real-world applications and transformative potential of ERC 4907, leading to a more dynamic digital asset market. As these partnerships develop, they promise significant changes in the landscape of NFTs and digital ownership.You may also like | How to Implement an On-Chain NFT AllowlistERC 4907 Use CasesGamingPlayers can rent rare in-game items or characters temporarily, allowing for access to premium content without a full purchase.Virtual Real EstateUsers can rent virtual plots of land or properties in metaverse platforms for specific events or time periods.Art and CollectiblesArtists can rent their works for exhibitions or shows, allowing more people to experience the art without ownership.Also, Explore | NFT ETFs | A Beginner's Guide to Investing in Digital AssetsRenting NFTs is a reasonable approachThe blockchain used the actual world as a source for the concept of renting. Instead of paying money to use something that the other party has, one party wants it but cannot afford to own it or doesn't need it. People adore the thought of living off the returns from their assets, exactly like in the real world. Rentable NFTs' primary concept is that they are a passive revenue source.What Advantages Does ERC 4907 Bring?Market LiquidityERC 4907 will enhance NFT renting and enable related derivatives across various use cases, such as gaming, art, and music. As the Metaverse and Web3 expand, more people will opt to rent NFTs instead of buying assets, increasing market liquidity over time.Easy Third-party IntegrationERC 4907, which establishes a single standard, will enhance collaboration and assist Ethereum's cross-platform ecosystem. This standard improves communication between all parties engaged in utility NFT leases for gaming, the metaverse, and membership cards by simplifying integration and reducing development costs.Moreover, third-party protocols employing ERC 4907 may oversee NFT usage rights without needing permission from the initial issuer. Others can swiftly do their own tasks when a project gives users this position. A PFP NFT, for instance, may be included in a platform that permits short-term rentals and simultaneously offers "rent-to-own" options via a mortgage platform without the original project's permission.Backward CompatibilityBy introducing an extended function set, the ERC 4907 standard can achieve full ERC-721 compatibility. Furthermore, there are a lot of parallels between the new functions provided in this standard and the current ERC-721 functionalities. This makes it possible for developers to embrace the new standard swiftly and simply. Future and current NFTs produced as standard ERC-721 can be wrapped to be compatible with ERC 4907 or upgraded to ERC 4907.Also, Read | How to Create a Compressed NFT on SolanaNeed of ERC 4907Renting Out AssetsOwners can lease their digital assets while maintaining ownership according to ERC 4907, which permits NFTs to be rented out. For asset holders, this means additional revenue prospects.Increased Digital Assets' ValueThis standard increases the functionality of NFTs and encourages their wider use across a range of industries, including gaming and virtual real estate, by allowing them to be rented.Innovative UsesIn the NFT space, the standard fosters innovation by creating opportunities for new applications including digital art exhibitions, virtual events, and game rentals.Also, Check | A Step-by-Step Tutorial of Building a Cross Chain NFT BridgeThings to Take Into Account When Implementing ERC 49071. In situations when the rental mechanism is not thoroughly monitored, users may take advantage of it. For example, they may rent an NFT for a very little time in order to swiftly transfer it without the owner's permission.2. Legal concerns may arise from renting digital assets, particularly if the NFTs include copyrighted content or other intellectual property. Users might have to make sure local laws are followed.Also, Discover | NFT-Based Loyalty Programs: Revamping Customer EngagementDetails of the ERC 4907 Interface:// function setUser(uint256 tokenId, address user, uint64 expires) external Main Purpose: Assigns a user to an NFT along with an expiration time. Parameter: tokenId: Unique Identifier of NFT user: the address of new user who can Use NFT exepires: duration until which the user can access the NFT Access-Control : Usually callable from an authorised address or the NFT owner. This guarantees that user access can only be modified byauthorised entities. // function userOf(uint256 tokenId) external view returns (address); Purpose: identifies the NFT's engaged user. Parameters: tokenId:Unique Identifier of NFT. Returns: The user's address. It returns the zero address (address(0)) in the event that the user has expired or if no user is allocated. // function userExpires(uint256 tokenId) external view returns (uint256); Purpose: retrieves the NFT user's expiration timestamp. Parameters: tokenId:Unique Identifier of NFT. Returns: The Unix timestamp indicating the expiration date of the user's access. There is no user when the value is 0. // Event UpdateUser(uint256 indexed tokenId, address indexed user, uint64 expires); Purpose: Emitted whenever a user is assigned or updated for an NFT. Parameters: tokenId: unique identifier of the NFT. user: Address of the new User. expires: The new expiration timestamp. Significance: Real-time tracking of user assignments is made possible by this event for both front-end apps and external services. Also, Read | NFT Domains | Revolutionizing Ownership in the Digital LandscapeERC 4907 Implementation// SPDX-License-Identifier: MIT pragma solidity ^0.8.0; // ERC721 Implementation contract MyERC721Token { struct Token { address owner; address approved; } // Mapping from token ID to token information mapping(uint256 => Token) private _tokens; // Mapping from owner to number of tokens mapping(address => uint256) private _balances; // Mapping from owner to operator approvals mapping(address => mapping(address => bool)) private _operatorApprovals; // Counter for token IDs uint256 private _tokenIdCounter; // Events event Transfer(address indexed from, address indexed to, uint256 indexed tokenId); event Approval(address indexed owner, address indexed approved, uint256 indexed tokenId); event ApprovalForAll(address indexed owner, address indexed operator, bool approved); // Mint a new NFT function mint(address to) public { require(to != address(0), "Cannot mint to zero address"); uint256 tokenId = _tokenIdCounter++; _tokens[tokenId] = Token(to, address(0)); _balances[to]++; emit Transfer(address(0), to, tokenId); } // Get the balance of an owner function balanceOf(address owner) external view returns (uint256) { require(owner != address(0), "Owner address cannot be zero"); return _balances[owner]; } // Get the owner of a specific token function ownerOf(uint256 tokenId) public view returns (address) { address owner = _tokens[tokenId].owner; require(owner != address(0), "Token does not exist"); return owner; } // Approve another address to transfer the specified token function approve(address to, uint256 tokenId) external { address owner = ownerOf(tokenId); require(msg.sender == owner, "Not the token owner"); _tokens[tokenId].approved = to; emit Approval(owner, to, tokenId); } // Get the approved address for a specific token function getApproved(uint256 tokenId) public view returns (address) { require(_tokens[tokenId].owner != address(0), "Token does not exist"); return _tokens[tokenId].approved; } // Approve or revoke permission for an operator to manage all tokens function setApprovalForAll(address operator, bool approved) external { require(operator != msg.sender, "Cannot approve oneself"); _operatorApprovals[msg.sender][operator] = approved; emit ApprovalForAll(msg.sender, operator, approved); } // Check if an operator is approved to manage all tokens of the owner function isApprovedForAll(address owner, address operator) external view returns (bool) { return _operatorApprovals[owner][operator]; } // Transfer ownership of a token function transferFrom(address from, address to, uint256 tokenId) external { require(msg.sender == from || msg.sender == getApproved(tokenId) || _operatorApprovals[from][msg.sender], "Not authorized"); require(_tokens[tokenId].owner == from, "Incorrect owner"); require(to != address(0), "Cannot transfer to zero address"); // Call before transfer hook _beforeTokenTransfer(from, to, tokenId); // Transfer the token _tokens[tokenId].owner = to; _tokens[tokenId].approved = address(0); _balances[from]--; _balances[to]++; emit Transfer(from, to, tokenId); } // Internal function to clear approval when transferring function _clearApproval(uint256 tokenId) internal { if (_tokens[tokenId].approved != address(0)) { delete _tokens[tokenId].approved; } } // Internal hook to be overridden function _beforeTokenTransfer(address from, address to, uint256 tokenId) internal virtual {} } // Interface for ERC 4907 interface IERC4907 { event UpdateUser(uint256 indexed tokenId, address indexed user, uint64 expires); function setUser(uint256 tokenId, address user, uint64 expires) external; function userOf(uint256 tokenId) external view returns (address); function userExpires(uint256 tokenId) external view returns (uint256); } // ERC 4907 Implementation contract ERC4907 is MyERC721Token, IERC4907 { // Custom errors error CanNotRentToZeroAddress(); error NotOwnerOrApproved(); error InvalidExpire(); struct TenantInfo { address tenant; uint64 expires; } mapping(uint256 => TenantInfo) internal _tenants; constructor() { // Minting initial tokens for (uint256 i = 1; i <= 10; i++) { mint(msg.sender); // Minting 10 NFTs } } function setUser(uint256 tokenId, address tenant, uint64 expires) public override { if (ownerOf(tokenId) != msg.sender && getApproved(tokenId) != msg.sender) { revert NotOwnerOrApproved(); } if (tenant == address(0)) { revert CanNotRentToZeroAddress(); } if (expires <= block.timestamp) { revert InvalidExpire(); } TenantInfo storage ref = _tenants[tokenId]; ref.tenant = tenant; ref.expires = expires; emit UpdateUser(tokenId, tenant, expires); } function userOf(uint256 tokenId) public view override returns (address) { TenantInfo storage ref = _tenants[tokenId]; if (ref.expires >= block.timestamp) { return ref.tenant; } else { return address(0); } } function userExpires(uint256 tokenId) public view override returns (uint256) { return _tenants[tokenId].expires; } // Override the transfer function to clear tenant info on transfer function _beforeTokenTransfer(address from, address to, uint256 tokenId) internal override { super._beforeTokenTransfer(from, to, tokenId); TenantInfo storage ref = _tenants[tokenId]; if (from != to && ref.tenant != address(0)) { delete _tenants[tokenId]; emit UpdateUser(tokenId, address(0), 0); } } } ConclusionWith the release of ERC 4907, which provides a flexible framework designed specifically for the growing NFT rental industry, non-fungible tokens (NFTs) have evolved tremendously. Its dual-role strategy not only makes rights allocation more clear but also lays the foundation for a range of partnerships and applications. This innovation comes at a perfect time, as it tackles the intricacy of the leasing space and keeps up with the exponential growth of digital assets.ERC 4907 represents an evolution in the NFT space by introducing rental functionalities, and providing new opportunities for monetization and interaction with digital assets. It opens the door to innovative business models and use-cases across various industries, enhancing the utility of NFTs beyond mere ownership.The NFT environment is about to change as ERC 4907 redefines digital asset leasing and develops popularity across several ecosystems. A future of innovation and fluidity in digital asset management is promised by the protocol, which also offers increased security, operational efficiency, and a multitude of opportunities. As a major protagonist in the story of digital innovation, ERC 4907 solidifies its position by setting new standards that not only predict future trends but also meet present needs. Need assistance with developing your NFT project, connect with our skilled blockchain and NFT developers to get started.References:https://github.com/tronprotocol/tips/blob/master/tip-4906.md https://ethereum-magicians.org/t/eip-6884-delegatable-utility-tokens-derived-from-origin-nfts/13837/https://github.com/ethereum/ERCs/blob/master/ERCS/erc-7507.md/https://github.com/ethereum/web3.py/issues/1351 https://github.com/OpenZeppelin/openzeppelin-contracts/blob/master/contracts/token/ERC721/IERC721.sol https://forum.openzeppelin.com/t/error-verifying-erc721-in-etherscan-file-import-callback-not-supported-with-github-imports/4198 https://soliditydeveloper.com/erc-1155 https://medium.com/coinmonks/erc-721-tokens-b83d7fc3e740 https://ethereum.stackexchange.com/questions/117365/executing-view-read-functions-on-gnosis-safe-with-raw-encoded-data/https://www.kaleido.io/blockchain-blog/how-to-create-and-deploy-an-erc-721-token https://github.com/OpenZeppelin/openzeppelin-contracts/issues/3659 https://hips.hedera.com/hip/hip-376

Technology: SMART CONTRACT , SOLIDITY more Category: Blockchain Development & Web3 Solutions

Tushar Shrivastava

24 Sep 2024

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