Security Guide for Smart Contracts

Please note that this guide provides general recommendations. Security audits and testing tailored to specific business logic and contract requirements are still necessary in actual projects.

1. Understanding the TRON Ecosystem

Differences between the TRON Virtual Machine (TVM) and the Ethereum Virtual Machine (EVM)

• While TRON shares similarities with Ethereum in the execution logic of the underlying virtual machine, differences exist in opcodes, resource models, and event handling mechanisms. Developers should thoroughly understand these distinctions to avoid potential security risks caused by directly applying EVM-centric patterns to the TVM.

TRC Standards and Interfaces

• Common token standards in the TRON ecosystem include TRC-10, TRC-20, and TRC-721 (NFT). These are similar to Ethereum’s ERC-20 and ERC-721 but differ in implementation details. Developers should carefully review and cross-reference the TRC standard specifications when implementing contract logic.

Network and Account Model

• On the TRON Mainnet, contract transaction execution consumes resources (Energy and Bandwidth). These resources’ consumption patterns and contract invocation costs differ from Ethereum’s gas model. Developers should carefully evaluate resource consumption and the potential for resource depletion during contract development and security audits.

2. Contract Security Design Principles

Principle of Least Privilege

• In contract design, ensure that only essential functions or roles execute high-risk operations, minimizing function call permissions that can critically impact the contract state.
• Implementing multi-role management or a multi-signature (multisig) mechanism is recommended to restrict critical operations, such as contract upgrades, core parameter modifications, and large-amount asset transfers.

Keep It Simple & Stupid (KISS) Principle

• The more complex the smart contract logic, the greater the risk of introducing unintended vulnerabilities or unexpected state changes. Developers should decompose contracts into smaller, focused modules designed according to the “Single Responsibility Principle” to avoid redundant and unnecessary features.

Strict Input and Output Data Validation

• Functions should check input parameters for valid boundary, type, and permission, and logically verify return values to prevent issues such as numerical overflows and erroneous state updates.

Safe Mode and Emergency Strategies

• Design an emergency stop (Circuit Breaker / Pausable) mechanism for contracts to halt critical functions or freeze the contract upon detecting significant security risks, thereby preventing further financial losses or the spread of erroneous states.
• Develop emergency repair or migration plans before project launch to avoid reactive and disorganized responses in the event of an incident.

3. Common Security Risks and Prevention Essentials

Reentrancy Attacks

• As one of the most well-known attacks on Ethereum, reentrancy also remains a concern on TRON. If a contract calls an external contract or sends TRX, the external contract might call back into the original contract’s function, potentially violating the original contract function’s security assumptions.

Typical prevention measures:

• Update the contract state before calling external contracts or performing transfers.
• Use function-level mutual exclusion mechanisms (such as mutex or reentrancyGuard); similar logic can be designed within the TVM framework.
• Ensure external calls occur as the last line of contract logic.

Integer Overflow/Underflow

• Solidity compiler versions on TRON can also encounter integer overflow and underflow issues (as seen in earlier compiler versions). Using a newer compiler (with built-in security checks) or manually incorporating a secure math library, such as SafeMath, is recommended.
• Developers should familiarize themselves with the security checks implemented by the compiler versions they use. If using an earlier version, be sure to incorporate SafeMath or equivalent protections.

Access Control Vulnerabilities

• Missing or inadequate permission modifiers or validation on contract functions can enable attackers to invoke administrative functions.
• Developers should manage critical functions using either a modifier (such as onlyOwner / onlyAdmin) or role-based access control components. Sensitive operations may require secondary confirmation via multi-signature contracts.

Random Number Security

• Generating random numbers on the blockchain is a common challenge, as they are susceptible to manipulation by miners or nodes. This also applies to the TRON network.
• Contracts that require random numbers (such as lottery or raffle contracts) should integrate off-chain random numbers or use a trusted third-party oracle. Random values generated locally via block.hash, now, or other similar methods are insecure.

Logic Flaws and Business Risks

• For contracts involving financial assets, business logic issues should also be considered in addition to code implementation. For example, the transfer logic, lock-up logic, and minting/burning functionalities of token contracts should be evaluated for potential abuse or unauthorized access.
• Independent threat modeling is necessary: Scrutinize each business functionality from an attacker’s perspective to assess its risk of manipulation or exploitation.

Upgrade and Migration Risks

• TRON smart contracts, once deployed, cannot be easily modified. When using proxy contracts or upgradeable contract architecture for contract upgrades or migrations, carefully address the security risks associated with the proxy pattern:
• Upgrade procedures require strict permission and multi-signature verification.
• Proxy contract logic can introduce complexities such as additional storage collisions and delegatecall vulnerabilities.

4. Security Development and Audit Process Recommendations

Use a Reliable Development Toolchain

• Select official or mature community-maintained TRON development tools (such as TronBox, TronGrid, and TronLink) and utilize established code auditing tools for static and dynamic testing.
• When choosing third-party libraries, ensure the versions you use are secure and reliable.

Phased Testing

• Unit Test: Test individual contract functions, particularly for core logic and high-risk permission functions.
• Integration Test: Conduct integration testing of the entire business process in a local private network environment or on a testnet.
• Security Audit: Use a professional audit team or an audit platform/tool for source code auditing and dynamic analysis of the contract.
• Bug Bounty Program: In the period surrounding Mainnet launch, encourage white hat hackers and the security community to participate in vulnerability discovery and offer rewards.

Log and Event Monitoring

• Design and trigger contract events effectively to enable blockchain explorers and monitoring scripts to track key state changes and detect potential anomalies.
• Set up real-time monitoring and alert thresholds for critical events, including transfers, permission changes, and upgrade operations.

Multi-Signature and Custody

• Introducing a multi-signature mechanism can significantly reduce the risk of single-point-of-failure when managing contract assets or performing critical contract operations.
• For large projects or projects involving high-value assets, consider using secure custody service providers or hardware wallets to manage private keys.

5. Operation and Continuous Security Assurance

Version Control and Traceability

• Implement version control for smart contracts. After contract deployment, promptly record and publicly disclose the contract address, ABI, source code hash, and other relevant information to facilitate tracking and auditing of updates by users and audit institutions.
• If performing contract upgrades or migrations, publicly disclose the upgrade process, explain the differences between old and new versions, and provide data migration plans.

Timely Response to Community and Industry Developments

• Follow security vulnerabilities, compiler bugs, developer warnings, and other relevant information released by the TRON or other security communities, and promptly patch potential issues.
• Continuously update threat models and security strategies to address emerging attack methods (such as flash loan attacks and oracle manipulation).

Compliance and Legal Risks

• If the project involves financial or securities attributes (such as exchanges, collateralized lending), consult with legal counsel and complete necessary filings to ensure regulatory compliance.
• Adhere to relevant laws, regulations, and industry best practices to protect user assets and privacy.