UsualUSDtb

High-Level Overview

The UsualUSDTB smart contract manages the UsualUSDTB ERC20 Token and acts as a wrapped version of the USDTB token. It allows users to wrap USDTB tokens into UsualUSDTB, adding enhanced functionality such as pausability, blacklist enforcement, and mint cap restrictions. It also supports permits and implements role-based access control to ensure secure operations. This contract is specifically designed to interact with the USDTB token while enforcing access control through a Registry Access Contract. Key features include wrapping, unwrapping, minting, and pausing operations.

Contract Summary

UsualUSDTB is an ERC-20 token with additional features that provide security and operational flexibility. It integrates with OpenZeppelin upgradeable modules for pausability and permit-based approvals. Moreover, it enforces blacklist restrictions to prevent interactions with malicious or sanctioned addresses and limits the maximum supply via a configurable mint cap.

Inherited Contracts

• ERC20PausableUpgradeable: Enables pausability of token transfers, ensuring operations can be halted in emergencies.

• ERC20PermitUpgradeable: Supports gasless approvals through EIP-2612 signatures, enabling off-chain approval of token transfers.

• ERC20Upgradeable: Provides the core ERC-20 token implementation.

Functions Description

Public/External Functions

• wrap(address recipient, uint256 amount): Wraps the specified amount of USDTB tokens into UsualUSDTB tokens for the recipient.

• wrapWithPermit(address recipient, uint256 amount, uint256 deadline, uint8 v, bytes32 r, bytes32 s): Wraps USDTB tokens using a permit signature for approval, enabling gasless wrapping.

• unwrap(address recipient, uint256 amount): Unwraps UsualUSDTB tokens into USDTB tokens, subject to role checks on the caller.

• setMintCap(uint256 newMintCap): Updates the mint cap for the token. Callable only by accounts with the USUAL_USDTB_MINTCAP_ALLOCATOR role.

• pause(): Pauses all token transfers. Callable only by accounts with the USUAL_USDTB_PAUSE role.

• unpause(): Resumes all token transfers. Callable only by accounts with the USUAL_USDTB_UNPAUSE role.

• blacklist(address account): Blacklists an address, preventing it from interacting with the token. Callable only by accounts with the BLACKLIST_ROLE.

• unBlacklist(address account): Removes an address from the blacklist. Callable only by accounts with the BLACKLIST_ROLE.

Functionality Breakdown

SC-Flows

Key Functionalities

• Wrapping: Users can wrap USDTB tokens into UsualUSDTB, making use of enhanced token features.

• Unwrapping: Users can unwrap UsualUSDTB tokens back into USDTB, subject to role checks.

• Mint Cap Enforcement: Ensures that the total supply of UsualUSDTB tokens does not exceed the configured mint cap.

• Blacklist Enforcement: Prevents blacklisted addresses from participating in token transfers.

• Pausability: Allows administrators to halt all token transfers during emergencies.

Constants

• USUAL_USDTB_UNWRAP: Role required to unwrap tokens.

• USUAL_USDTB_PAUSE: Role required to pause the contract.

• USUAL_USDTB_UNPAUSE: Role required to unpause the contract.

• USUAL_USDTB_MINTCAP_ALLOCATOR: Role required to update the mint cap.

• BLACKLIST_ROLE: Role required to blacklist/unblacklist accounts.

• USUAL_USDTB_DECIMALS: Set to 18 decimals for the token.

Safeguards Implementation

• Pausability: The contract integrates pausability to ensure all token transfers can be halted in emergencies. Only accounts with the appropriate roles can pause/unpause the contract.

• Role-Based Access Control: Sensitive operations such as pausing, unwrapping, blacklisting, and updating the mint cap are restricted to accounts with specific roles. This ensures that only authorized entities can perform these operations.

• Mint Cap Enforcement: The total supply of UsualUSDTB tokens is capped by a configurable limit, ensuring supply control.

• Blacklist Enforcement: The contract prevents interactions with blacklisted addresses, safeguarding the token economy from malicious actors.

• Safe Type Conversion: The contract includes _safe96() function to safely convert uint256 to uint96 for mint cap storage, preventing overflow issues.