Best Practices for Developing Secure Web3 Applications: Building Trustworthy DApps

Developing trustworthy DApps is crucial for building user trust, ensuring security, providing a good user experience, and driving the adoption of blockchain technology.Trustworthy DApps provide users with a secure, transparent and decentralized interactive environment, laying a solid foundation for the sustainable development and widespread application of blockchain technology. We will mainly explain the technical stack for building DApps from the following five aspects:

1. Smart contract development: Ensure that smart contracts are designed in line with best practices and security principles, and follow a modular and extensible architecture to allow for future upgrades and modifications.
2. Smart contract testing: Conduct comprehensive unit testing, integration testing and system testing to ensure the correctness and stability of the contract. Additonally, the robustness and security of the contract are checked by simulating various scenarios and attacks.
3. Front-end development: Ensure a user-friendly and easy-to-use user interface that securely interacts with smart contracts. Implement necessary verification and authorization mechanisms to protect user privacy and assets.
4. Middleware development: Ensure the security and reliability of middleware to protect user data and transactions through appropriate encryption and authentication mechanisms. At the same time, middleware also needs to provide efficient interfaces and functionalities so that the front end can interact seamlessly with smart contracts.
5. Smart contract deployment: Ensure the correctness and integrity of the contract during the deployment process, and perform necessary data migration and transfer. Choose appropriate deployment tools and networks, and follow best practices and security guidelines.

1 Smart contract development

1.1 Characteristics of smart contracts

Smart contracts are the core components of DApps, and they define the logic and functionality of DApps. Smart contracts have unique programming languages, including Solidity, Vyper, Move, and Rust. Understanding the characteristics of smart contracts is very important for developing DApps. Here are some key features:

• Transactional nature: During the execution process, smart contracts either all be executed successfully or all be rolled back to an unmodified state. This requires careful attention to the design of function APIs in the process of writing smart contracts, avoiding parameter overloading and handling errors cautiously.
• Error handling: Common error-handling methods include using “require” statements to pass error messages or using “revert” statements to customize error types. These error-handling methods will cause transaction failures and require capturing custom error types on the front-end.
• Execution cost: The state storage of smart contracts incurs gas fees. Therefore, when designing storage objects, you must make good use of the declared memory space to avoid excessive memory usage. Different data structure declarations at different locations will incur different costs, and functions that change state will consume gas.
• Immutability: Once a smart contract is deployed, it cannot be dynamically replaced or upgraded. Therefore, you need to consider whether to rely on an upgradeable architecture and ensure the upgradeability of the contract before deployment.
• Permissions and visibility: The contract is transparent to everyone in the network, so sensitive data should not be stored in the contract, and reliance on the blockchain’s state as the core business logic criterion should be avoided. It is recommended to use permission control mechanisms such as Ownable and AccessControl.
• Security: The security of the contract is very important and must follow best security practices, including contract code security guidelines and adequate test cases. Don not trust untested contract code and subjectively expect it to function correctly.

1.2 Security Practices

In DApp development, it is crucial to ensure that smart contracts are secure and easily auditable.Here are some best practices and recommendations for keeping smart contracts secure:

• Standardized development framework: Using standardized development frameworks can help improve the credibility of smart contracts. These frameworks, usually created and maintained by experienced developers and security experts, contain verified and optimized code and patterns. By using these frameworks, developers can avoid common security issues and be able to use code that has been tested and audited to improve the security of their contracts. For example, OpenZeppelin is a widely used and proven smart contract development framework that provides some standard contract templates and libraries to help developers build secure and reliable contracts.
• Using events for logging: Recording the execution details of smart contracts using events helps better track the contract’s functions and operations. Events can be defined and triggered in the contract, recording the details of an operation, such as the caller’s address, timestamp, and parameters passed to the function. This log information is extremely valuable for auditing contracts and identifying potential vulnerabilities. For example, in a crowdfunding contract, you can define an event to record the details of each donation, including the donor’s address and donation amount. In this way, all operations and changes to the contract can be recorded, making it easier for auditors to review and analyze.
• Implement access control: Access control is a mechanism for controlling who can access certain resources or perform certain operations and authenticate them before accessing or performing them. In smart contracts, access control can be implemented using modifiers, which can be added to functions to check that specific conditions are met before executing the function. Implementing access controls ensure that only authorized entities can perform specific operations or access sensitive data. For example, in a voting contract, a modifier can be defined to verify that only specific addresses can perform voting operations, ensuring that only authorized users can participate in the voting process.
• Follow the principle of least privilege: The principle of least privilege requires that each user be granted only the minimum access permissions required to perform their job. In smart contracts, least privilege can be achieved through access control mechanisms. By implementing access control and following the principle of least privilege, you can limit the permissions granted to each entity to ensure they can only perform necessary operations. For example, in a multi-user contract, different permission levels can be defined for each user, and only the necessary permissions are granted to the user based on their identity and needs to prevent abuse and unnecessary operations. Doing so reduces the risk of the contract being compromised because even if an account is compromised, the attacker can only perform restricted actions.
• Multi-signature: Using multi-signature for key transactions is an important measure in ensuring smart contract security. Multi-signature requires that multiple parties must sign before a key transaction can be executed to complete the transaction. This mechanism can provide additional security and mitigate some potential attack risks, such as replay attacks and transaction malleability.
• Explain timers and timeouts: Since the transaction execution time in the blockchain network is uncertain, smart contracts are vulnerable to attacks that exploit timing issues, such as predicted random number attacks, front-running attacks, sandwich attacks, etc. To mitigate attacks against these timing issues, using timers and timeout mechanisms is an effective approach. Timers can be used to schedule the execution of functions in a contract at specific times, thereby avoiding reliance on the execution time of the blockchain network. The timeout mechanism can limit the execution time of certain functions in the contract to ensure that they do not continue to execute indefinitely.

1.3 Smart Contracts Upgradability

Smart contract upgrade refers to the process of updating or modifying smart contracts that have been deployed on the blockchain.Smart contract upgrades involve changing the business logic of a smart contract while preserving the state of the contract. Smart contract upgrades allow developers to improve the logic, functionality, or security of the contract to adapt to new needs or fix problems in existing contracts. Upgrading smart contracts is a complex activity that requires a high degree of caution to prevent vulnerabilities.

Smart contract upgrades typically require the following steps:

• Write new contract code: Developers write new contract code as needed, including improvements to the original contract. New code should undergo rigorous testing to ensure its correctness and security.
• Deploy a new contract: The new contract code needs to be deployed through a different contract address from the original contract. Before deploying a new contract, developers need to ensure that data migration or transfer is properly handled during the upgrade process.
• Migrate or transfer data: If the smart contract upgrade involves the migration or transfer of data, developers need to design corresponding mechanisms to ensure that the data is correctly migrated or transferred in the new contract. This usually involves the process of data interaction and conversion with the old contract.
• Update the contract address or interface: Once the new contract is successfully deployed, developers need to update the applications or user interfaces that interact with the contract to ensure that they adapt to the address or interface of the new contract.

2 Smart Contract Testing

Smart contract testing refers to the application of various testing methods and techniques to verify the functionality, security, performance and correctness of the contract. Smart contract testing aims to uncover potential issues, vulnerabilities, and errors in the contract and ensure that the contract functions as expected under various circumstances.

2.1 Why is Testing Important?

Smart contract testing is an important practice in smart contract development for several important reasons:

• Verify smart contract functionality: Smart contracts are codes used to perform specific functionalities, such as transfers, status updates, etc. Unit testing helps verify that each function of the contract work as expected. This helps identify and fix potential bugs, ensuring that the contract’s behavior and logic are correct.
• Ensure security: Smart contracts often involve processing and managing assets, such as cryptocurrencies. Therefore, the security of the contract is crucial. Unit tests checks whether the contract is vulnerable to common attacks and threats, such as reentrancy attacks and integer overflow. This helps to identify and fix potential security vulnerabilities and ensure the security of the contract.
• Improve code quality: Unit testing helps developers write high-quality code. By writing test cases and assertions, developers can verify the correctness of their code and ensure that it works properly under various circumstances. This helps improve the robustness, reliability, and maintainability of your code and reduces the cost of future maintenance.
• Supports reconstruction and expansion: During smart contract development, as requirements change, the contract may need to be reconstructed or expanded. Having a comprehensive unit test suite ensures that existing functionality and logic are not broken during reconstruction or expansion. This helps maintain code stability and simplifies future development and maintenance work.
• Continuous integration and deployment: In a development environment of continuous integration and deployment, unit testing is a crucial step. By automatically running unit tests, potential issues in the code can be discovered and resolved promptly to ensure its quality and reliability. This contributes to improving the efficiency of the development team and accelerating product release speed.

2.2 Which Aspects are Tested?

When testing smart contracts, we mainly focus on the following aspects:

• Contract functionality and behavior: The main goal of testing smart contracts is to verify that the contract functions as expected. This includes testing that the various functions and methods of the contract execute correctly and are consistent with expected results. For example, in the case of a transfer contract, we can test whether it can correctly implement the transfer function of funds.
• Edge cases of the contract: We also need to test the behavior of the contract in various edge cases. This includes testing the boundary values ​​of input parameters, such as minimum values, maximum values, null values, etc., as well as testing the contract’s ability to handle abnormal situations, such as processing invalid inputs, processing unauthorized operations, etc. By testing edge cases, we can discover potential problems and vulnerabilities that may exist in the contract.
• Contract security: Security is an important aspect in smart contract testing.We need to test the contract for potential security vulnerabilities, such as reentrancy attacks, integer overflows, unauthorized access, etc.Through security audits and testing for specific vulnerability types, we can identify and fix security issues in contracts to ensure the security of user assets.
• Contract performance and scalability: Smart contracts need to have good performance and scalability to handle a large number of transactions and users. Therefore, we need to conduct performance testing and stress testing to verify the performance and stability of the contract under high load and concurrent user scenarios. By testing the performance and scalability of a contract, we can optimize the design and implementation of the contract to improve its throughput and response time.
• Contract integration and compatibility: If the smart contract needs to be integrated with other components or services, we need to conduct integration tests to verify whether the contract cooperates properly with other components. This includes integration of front-end applications, interaction with other contracts, etc. Additionally, we also need to test the compatibility of the contract in different Ethereum clients and network environments to ensure the consistency and reliability of the contract in different environments.

2.3 Testing methods

• Unit testing: Unit testing is a method of testing various functions and methods in smart contracts. By writing test scripts that simulate the contract’s input and environment, and asserting the contract’s output, we can verify if the contract functions as expected.
• Integration testing: Integration testing is used to test if different components interact correctly. In smart contract development, integration tests can be written to test the integration of the contract with front-end applications or other services such as blockchain nodes or databases. Integration testing ensures that the contract works properly with other components and verifies the functionality and performance of the overall system.
• Property-based testing: Property-based testing focuses on whether the behavior of the contract satisfies predefined properties. These properties are assertions about the behavior of the contract that should always remain true under different scenarios. Static analysis and dynamic analysis are two common techniques used to perform property-based testing. The static analyzer accepts the source code of a smart contract as input and outputs a result stating whether the contract satisfies a certain property. Dynamic analysis generates symbolic or concrete inputs to smart contract functions to see if any execution traces violate specific properties.
• Security Audit: Security audit is also manual testing. By carefully reviewing the code and logic of the contract, and using professional auditing tools and techniques, potential vulnerabilities and security risks can be identified. Security audits are critical to protecting the assets in the contract and the security of users. If you have smart contract audit needs, please contact Salus, who will provide you with high-quality services.

2.4 Testing tools

Foundry and Hardhat are two popular development tools for testing smart contracts.

Foundry is a TypeScript-based smart contract development framework that provides a powerful set of tools and libraries for creating and testing Ethereum smart contracts.

• Foundry uses Mocha and Chai, two popular JavaScript testing frameworks, to write and execute a variety of test cases.
• Foundry provides some built-in assertion functions for verifying the expected behavior of smart contracts.
• Foundry also supports testing with a simulator to avoid consuming resources and fees on the actual Ethereum network.

Hardhat, on the other hand, is a powerful Ethereum development environment for writing, deploying and testing smart contracts.

• It integrates with the Mocha and Chai testing frameworks, as well as other useful tools such as Ethers.js and Waffle.
• It provides some built-in assertion functions for verifying the behavior and state of smart contracts.
• Italso supports the use of virtual machines for testing to avoid operations on the actual Ethereum network.

When using Foundry or Hardhat for smart contract testing, the following aspects may be tested:

• Whether the functionality and logic of the smart contract works as expected.
• Whether the contract interacts correctly with other contracts.
• Whether the contract handles abnormal situations correctly.
• Whether the state change of the contract is correct.
• Whether the contract is deployed and used correctly in different network environments.

These tools also provide additional features such as code coverage analysis and performance testing to help developers better evaluate and improve the quality and performance of their smart contracts.

3 Front-end development

3.1 Choose a front-end framework

In DApp development, choosing an appropriate front-end framework is very important for developing secure and trustworthy front-end applications.

3.1.1 Ethers.js

Ethers.js is a JavaScript library used for building DApp frontends. It is the preferred choice for many developers building DApp frontends. Many well-known DApp projects use ethers.js to interact with the Ethereum network and operate smart contracts.

It provides the following key features:

• Ethereum account management: Ethers.js allows you to generate and manage public keys, private keys and addresses for Ethereum accounts. You can use these accounts to conduct transactions, call smart contract methods, and more.
• Smart contract interaction: Ethers.js provides a concise set of APIs for interacting with smart contracts on Ethereum. You can use ethers.js to deploy smart contracts, call contract methods, retrieve contract state, etc. It also provides type-enhanced smart contract encoding and decoding capabilities for easier and more reliable interaction with smart contracts.
• Transaction creation and signing: With ethers.js, you can create and send Ethereum transactions. Ethers.js provides a simple interface to build transaction objects and supports signing transactions. This allows you to send Ether and perform contract operations in a secure manner.
• Other functionalities: Ethers.js provides many other useful functionalities, such as Ethereum unit conversion (e.g., from Wei to Ether), handling Ethereum events ( Such as monitoring contract events) and subscribing to blockchain events, etc. These features make it more convenient and efficient when building DApp front-ends.

For DApp front-end building, ethers.js provides the following advantages:

• Simple and easy to use: Ethers.js provides an intuitive API that makes interacting with the Ethereum blockchain simple and easy.
• Security: Ethers.js provides secure methods to handle private keys and signed transactions to ensure the safety of users’ assets.
• Feature-rich: Ethers.js provides many useful functions, such as Ether unit conversion, handling Ethereum events, etc., simplifying the development process.

For DApp front-end building, ethers.js has the following disadvantages:

• Learning curve: For beginners, it may take some time and effort to learn and understand the concepts and workings of Ethereum.
• Dependency on the Ethereum network: The functionality of ethers.js relies on the availability and stability of the Ethereum network. If there is a problem with the network, it may affect the normal operation of DApps.

3.1.2 React

React is a popular front-end framework for building user interfaces. While React itself does not directly provide functionality for interacting with the blockchain, you can integrate React with the blockchain to implement functionality for interacting with the blockchain in the following ways:

• Using Web3.js: Web3.js is a JavaScript library for interacting with the Ethereum network. You can introduce Web3.js into your React project and use it to connect to the Ethereum network, deploy and call smart contracts, send transactions, and more. With Web3.js, you can communicate with Ethereum nodes and perform operations related to blockchain interaction.
• Using ethers.js: Ethers.js is another popular JavaScript library for interacting with the Ethereum network. It provides a concise set of APIs for handling Ethereum accounts, deploying and calling smart contracts, sending transactions, and more. You can use ethers.js in your React project to implement functionality for interacting with the blockchain.
• Using blockchain explorer APIs: Some blockchain explorers, such as Etherscan or Infura, provide APIs that allow developers to interact with the Ethereum network through a RESTful interface. You can use these APIs in React projects to obtain blockchain data, query transactions, obtain contract information, etc.
• Use wallet integration libraries: Some wallet integration libraries (such as MetaMask or WalletConnect) provide functionality to interact with the Ethereum network and provide convenient user interfaces and authentication. You can use these libraries in your React project to implement the integration of user wallets so that users can conduct transactions and interact with smart contracts.

The method of integrating React with blockchain interaction can be combined with React’s component development model. You can create specialized components to handle the logic and user interface for interacting with the blockchain. By interacting with the blockchain network, you can implement functions such as querying account balances, executing contract methods, and monitoring blockchain events.

Security and privacy should be prioritized when interacting with the blockchain. It is important to ensure proper handling of private keys and signing transactions, and limit user permissions for sensitive operations during interactions. Use the best security practices and follow the specifications and recommendations of blockchain networks to ensure the security and reliability of your applications.

Compared with ethers.js, React has the following advantages when interacting with the blockchain:

• Strong ecosystem: React has a large developer community and rich third-party library support. This means you can easily find libraries and tools that integrate with React to support interaction with the blockchain. The broad support of the React ecosystem can provide you with more solutions and resources.
• Component development: React’s component development model makes building functions that interact with the blockchain more modular and maintainable. You can encapsulate the logic and user interface for interacting with the blockchain into independent components, making code organization and reuse clearer and more convenient.
• Virtual DOM: React uses virtual DOM technology to minimize DOM operations and improve performance and rendering efficiency by comparing the difference between the two states before and after. This is very helpful for handling large amounts of blockchain data and frequently updating interfaces.

However, compared with ethers.js, React has the following disadvantages when interacting with the blockchain:

• Longer learning curve: If you are not familiar with React, mastering the basic concepts and working methods of React may require some learning efforts. This may extend the time it takes for you to implement functionality to interact with the blockchain.
• Integration complexity: React’s flexibility and freedom may introduce relative complexity when integrating with blockchain. You’ll need extra work to ensure compatibility between React and the blockchain libraries and handle integration issues that may arise.

In contrast, ethers.js is a JavaScript library designed specifically for interacting with the Ethereum network, offering a concise API for direct and straightforward interaction with Ethereum. Compared to React, ethers.js may focus more on interacting with Ethereum, providing more blockchain-related features and tools.

However, the advantages of using React to interact with the blockchain lie in its powerful ecosystem, the benefits of component-based development, and the performance advantages brought by virtual DOM technology. This makes React a flexible, scalable and efficient choice, especially suitable for the development of large and complex applications.

3.2 Setting up a Scaffold project

When developing a DApp, after selecting a suitable front-end framework, the next step is often to build a scaffold project. A scaffold serves as a starting point or foundation that provides a default project structure, configuration, sample code, and tools. By using scaffold, developers can avoid the tedious work of building an application from scratch and instead develop quickly based on existing default settings and sample code. Scaffold can also provide some best practices and implementation of common functions to assist developers in following the best development process.

3.2.1 Key components of a scaffold

Scaffold for DApps usually includes the following key components:

• Smart Contracts: The scaffold provides one or more sample smart contracts that handle the business logic of the application. These contracts define the functionality and behavior of the DApp.
• Front-end interface: Scaffolds usually contains a basic front-end interface for interacting with users and demonstrating the functionality of the DApp. These interfaces can be built using technologies such as HTML, CSS, and JavaScript.
• Test scripts: The scaffold provides some sample test scripts for verifying the correctness and reliability of smart contracts. These test scripts can help developers write and run automated tests to ensure that DApps run correctly under different circumstances.
• Configuration files: Scaffolds usually contain some configuration files for configuring the development environment, deploying smart contracts, connecting to the Ethereum network, etc. These configuration files can be customized according to the developer’s needs.

3.2.2 Considerations when setting up a scaffold?

When building a DApp scaffold project, you need to consider blockchain network connections, the introduction of Web3 libraries, security, integration of front-end frameworks and libraries, testing, documentation, etc.

• Choose an appropriate scaffold tool: It is very important to choose a scaffold tool that is suitable for your DApp development. There are some commonly used scaffold tools such as Create React App, Vue CLI, etc. They all provide some default configurations and commands to quickly create and run a basic DApp project.
• Configure blockchain network connection: Depending on the blockchain network used by your DApp, you need to configure the network nodes connected to it. Typically, you need to provide the URL of the network node, port number, and other necessary authentication information. This way, your DApp project can interact with the blockchain network.
• Introduce appropriate Web3 libraries: In DApp development, you need to use Web3 libraries to interact with the blockchain. According to the blockchain platform you choose, select the corresponding Web3 library and introduce it into the project. For example, if you use Ethereum as the underlying blockchain, you can use Web3.js or ethers.js to communicate with Ethereum.
• Security considerations: Security is very important in DApp development. Make sure your scaffold project includes some common security measures, such as preventing cross-site scripting (XSS) attacks, preventing replay attacks, etc.You can use some security-related libraries or frameworks, such as those provided by OpenZeppelin.
• Integrate front-end frameworks and libraries: Choose the front-end frameworks and libraries that suit your DApp project and integrate them in your scaffold project. Common choices include React, Vue, etc. Make sure these frameworks and libraries are preconfigured in your scaffold project and can run smoothly.
• Add tests: It is very important to add tests in your scaffold project. You can choose a suitable testing framework, such as Jest, Mocha, etc., and write unit tests and integration tests to ensure the quality and stability of the code.
• Documentation and sample code: Detailed documentation and sample code can be very helpful in scaffold projects. This helps other developers better understand the structure and functionality of the project and get started quickly.

3.2.3 Popular scaffolds

When it comes to Ethereum-based web application scaffolds, there are several popular options. Here is an introduction to the three main scaffolds, including their main functions, features, and a comparison of their advantages and disadvantages.

Truffle

• Main functions: Truffle is a complete Ethereum development framework that provides smart contract compilation, deployment and testing tools, as well as the function of interacting with the Ethereum network. It also includes a powerful development environment for rapid development and testing of DApps.
• Features: Truffle provides a powerful set of command line tools and development environment to help you manage smart contracts, test and deploy DApps. It also supports Solidity and JavaScript and has a rich plugin ecosystem.

Embark

• Main functions: Embark is an Ethereum development framework for building decentralized applications. It provides easy-to-use tools and command-line interface for developing, testing, and deploying Ethereum smart contracts and DApps.
• Features: Embark integrates some popular front-end frameworks and libraries, such as React, Vue, etc., making it easier to develop DApps. It also provides a powerful plug-in system to extend its functionality.

scaffold-eth

• Main functions: scaffold-eth is an Ethereum-based web application scaffolding designed to help developers quickly build Ethereum DApps. It provides a complete set of tools and templates, including front-end interfaces, smart contracts, test scripts, etc.
• Features: Scaffold-eth uses Hardhat as a smart contract development framework, supports Solidity and TypeScript, and integrates some useful tools and libraries. It provides sample code and tutorials to help developers quickly get started with Ethereum development.

3.3 Front-end dependencies

In DApp front-end development, it is recommended to use some excellent front-end libraries to reduce workload and improve code delivery quality. Here are some commonly used front-end libraries:

• wagmi: wagmi provides a wealth of React hooks to complete the process of interaction between the DApp front-end and the contract. It simplifies the interaction process with contracts, making it easier for developers to handle operations such as transactions and contract calls.
• useDApp: useDApp is a complex React hooks library that supports multicall.js. It provides some convenient functions, such as handling multiple contract calls, handling Ethereum transfers, handling EIP-712 signatures, etc.
• Siwe: Siwe is a library for implementing the wallet login process. It provides a simple and secure way to implement wallet login and authentication, and integrates with other libraries and tools.
• i18next and react-i18next: If you plan to provide multi-language versions and instrumentation, you can use libraries such as i18next and react-i18next. They provide a convenient way to implement multi-language support and allow developers to easily switch and manage different languages ​​in the front-end interface.

4 Middleware Development

In DApp development, middleware often sits between the front-end application and the blockchain network. It acts as a middle layer between front-end applications and the underlying blockchain, handling and managing interactions with the blockchain.

4.1 Functions of Middleware

Middleware can perform the following functions:

• Wallet connection and authorization management: The middleware can provide wallet connection functions, communicate with the user’s wallet and manage the user’s authorization status. It handles operations such as wallet connection, login and logout, and manages user authentication and permissions.
• Transaction processing and signing: Middleware can handle the interaction with the contract and is responsible for constructing transactions, signing them, and sending transactions to the blockchain network. It can handle the life cycle of transactions, including constructing transactions, processing transaction status, and event monitoring.
• Data caching and querying: Middleware can cache and query contract data to improve application performance and response speed. It caches the results of a contract’s view function calls, updating and refreshing the cache as needed.
• Event monitoring and processing: Middleware can monitor contract events on the blockchain and perform corresponding operations when the events are triggered. It handles subscribing, parsing, and responding to events, and updates the state and interface of the front-end application.
• Error handling and logging: Middleware can handle errors and abnormalities during interaction with the blockchain and provide appropriate error handling and logging mechanisms. It can catch and handle errors and provide useful error information and feedback to front-end applications.

4.2 Middleware tools

In DApp development, you may use the following middleware tools to achieve the required functionality. These middleware tools can help you simplify the DApp development process and provide functions such as interaction with the blockchain, wallet connection and authorization management, and data management. Which tools to use depends on your needs and technology stack.

• Web3.js: Web3.js is a JavaScript library for interacting with the Ethereum network. It provides a series of APIs for connecting to the Ethereum network, instantiating contracts, sending transactions, reading contract data and other operations.
• ethers.js: ethers.js is another popular JavaScript library for interacting with Ethereum. It provides functionality similar to Web3.js, including connecting to the Ethereum network, instantiating contracts, signing transactions, etc.
• Metamask: Metamask is a commonly used Ethereum wallet plug-in that can be integrated with Web3.js or ethers.js to provide user wallet connection and transaction signing functions. Through Metamask, users can authorize DApps to access their wallet addresses and perform trading operations.
• Drizzle: Drizzle is a state management library based on Web3.js, specially designed for DApp development. It can help you manage the state of your DApp, interact with smart contracts, and provides some convenient functions, such as automatic event subscription and state update.
• Truffle Suite: Truffle Suite is a development suite for Ethereum DApp development, which includes tools such as the Truffle framework, Ganache private chain, and Drizzle. The Truffle framework can be used to compile, deploy, and test smart contracts; the Ganache private chain can be used for local development and debugging; and Drizzle can be used for state management and interaction with smart contracts.
• Infura: Infura is a platform that provides Ethereum node hosting services. It helps you easily connect to the Ethereum network and interact with the blockchain through APIs without having to run and maintain a node yourself.
• IPFS: If your DApp needs to store and retrieve large amounts of files or data, you may consider using IPFS (InterPlanetary File System), a peer-to-peer distributed file system that provides high availability and decentralized storage.

4.3 Security Considerations

Security should always be prioritized for DApps when interacting with wallets and contracts. It is important to ensure you use trusted connectors, verify wallet addresses and transaction state, perform input validation and data encryption, and perform regular security reviews and vulnerability fixes.

Wallet connection security:

• Use a trusted wallet connector: Ensure the wallet connector you use is verified and trusted. Use well-known connectors such as MetaMask, WalletConnect or Portis.
• User authorization restrictions: When a user authorizes a wallet connection, make sure the user understands the wallet they are connecting to and only authorizes permissions relevant to your application. Avoid requesting unnecessary permissions.
• Wallet address verification: Before using a wallet address, verify its correctness. The API provided by the wallet connector can be used to verify that the address provided by the user matches the address of the connected wallet.

Security in write operations with contracts:

• Transaction Confirmation and Signing: Before executing write operations with contract, make sure to use the wallet connector to confirm and sign the transaction. This ensures that transactions are authorized and signed by the user, providing an additional layer of security.
• Input validation: Input validation is always performed before user-provided data is passed to the contract for write operations. Ensure that input data is in the expected format and range to prevent problems caused by malicious input.
• Transaction state monitoring: After submitting a transaction, monitor the transaction state to ensure that the transaction is successfully confirmed and included in the blockchain. This allows timely updates on the front-end state and provides feedback to users.

Security in wallet login and signing operations:

• Use the signature function provided by the wallet: For operations that require a signature (such as login or other sensitive operations), use the signing function provided by the wallet instead of passing sensitive data to the contract for processing. This ensures that data is signed and encrypted locally, protecting users’ private keys and sensitive information.
• Data Encryption: Ensure data is properly encrypted when performing wallet logins or other sensitive operations. Encryption algorithms and security protocols can be used to protect the confidentiality of data.

Security review and bug fixes:

• Security review: For applications involving wallet and contract interaction, regular security reviews are necessary. Make sure your code and application architecture adhere to best security practices and evaluate and fix potential bugs.
• Bud fixes: If a security vulnerability or bug report is discovered, promptly fix and update your application. Prompt response and remediation of possible vulnerabilities are important steps in ensuring application security.

5 Smart Contract Deployment

Deploying a contract refers to deploying smart contracts onto the blockchain network for execution and use on the blockchain.

5.1 Considerations

• Smart contract bytecode: Contract bytecode is machine code generated by compiling smart contract source code. It is the actual execution code of the smart contract and is used to deploy the contract on the blockchain. Bytecode is a hexadecimal string that represents the logic and functionality of a contract and is the core part of executing contract operations on the blockchain.
• Gas: On the Ethereum network, each transaction requires a certain amount of gas to execute. Deploying smart contracts is no exception, requiring sufficient gas to cover the computational and storage resources required for contract deployment. The amount of gas depends on the complexity and size of the contract, as well as the congestion level of the network. You need to set a gas limit, which is the maximum amount of gas allowed to be used, to ensure successful contract deployment.
• Deployment script or plugin: A deployment script or plugin is a tool used to automate and simplify the contract deployment process. It can be a script file that contains the steps and instructions required to deploy the contract; or it can be a plug-in that is integrated into a development tool or framework to provide convenient deployment functions. This way, you can automate contract deployment by running scripts or using plugins, reducing the complexity of manual operations.

5.2 Tools for Smart Contract Deployment

You can deploy smart contracts to the blockchain platform through the following tools:

Remix: Remix is ​​an integrated development environment that can be used to develop, deploy and manage Ethereum smart contracts. You can use Remix to compile and debug smart contracts, and deploy them through its user interface.

• Remix official website
• Remix’s documentation

Tenderly: Tenderly is a Web3 development platform that provides debugging, observability, and infrastructure building blocks for developing, testing, monitoring, and operating smart contracts. You can use Tenderly for smart contract debugging and monitoring.

• Tenderly official website
• Tenderly’s documentation

Hardhat: Hardhat is a development environment for compiling, deploying, testing, and debugging Ethereum software. You can use Hardhat to write deployment scripts and perform deployment operations.

• Hardhat official website
• Hardhat’s documentation on deploying contracts

Truffle: Truffle is a development environment, testing framework, deployment channel and other tools for developing Ethereum smart contracts. You can use Truffle to write deployment scripts and perform deployment operations.

• Truffle official website
• Truffle documentation on network and application deployment

Thirdweb: Thirdweb is a tool that makes it easy to deploy any contract to any EVM-compatible blockchain using a single command.

• Thirdweb’s documentation

It is essential to rigorously test and audit smart contracts before deploying them on the blockchain. If you are interested in smart contract auditing, please contact us, and we will collaborate with you to provide professional auditing services, ensuring the security and reliability of your contracts.. If the smart contract deployed to the blockchain still has problems, upgrades may be necessary.

6 Conclusion

Building a trustworthy DApp requires focusing on security, stability and user experience in five aspects: smart contract development, smart contract testing, front-end development, middleware development, and smart contract deployment. Through comprehensive design, testing and implementation, the reliability and trustworthiness of DApps in the blockchain environment can be ensured.

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