Bsc Bridge

Basic Contract Information

Contract Name: Bsc Bridge

Dependencies:

• @openzeppelin/contracts-upgradeable

• @openzeppelin/contracts

• Custom interface IBscBridge

Inheritance:

• Initializable

• PausableUpgradeable

• OwnableUpgradeable

• UUPSUpgradeable

Core Functions

1. Role Permission Management

• Relayers: A whitelist of authorized relayer addresses managed through mapping(address => bool)

• Only contract Owner can manage relayer list through addRelayer()/removeRelayer()

• Relayers have permission to call mintLLA() for cross-chain minting

• Owner: Has highest privileges: upgrade contract, pause/unpause, set token address, manage funds, etc.

2. Cross-chain Minting Process

mintLLA() Function Logic:

function mintLLA(address user, uint256 amount, bytes32 txHash)

1. Input Validation:

• User address validity (user != address(0))

• Minting amount positive (amount > 0)

• Transaction hash uniqueness (!processedHashes[txHash])

2. State Update:

• Mark transaction hash as processed (processedHashes[txHash] = true)

3. Core Operation:

• Call LLA token contract’s mint() method to mint tokens for user

3. Emergency Handling Mechanism

Fund Withdrawal:

function emergencyWithdraw(address tokenAddress, address to, uint256 amount)

• Allows Owner to withdraw any ERC20 tokens

Contract Pause:

function pause()/unpause()

Security Mechanisms

1. Protection Measures

Mechanism	Implementation
Replay Attack Protection	processedHashes mapping records processed transaction hashes
Permission Isolation	Role separation through onlyOwner and onlyRelayer
Input Validation	Critical parameter non-zero checks (address, amount)
Upgradability Control	UUPS proxy pattern + _authorizeUpgrade only allows Owner operation

Architecture Flow Chart