​
Import Required Libraries

First, we need to import the necessary contracts and libraries:

pragma solidity ^0.8.24;

import "@inco/lightning/src/Lib.sol";

import "@openzeppelin/contracts/access/Ownable2Step.sol";

​
Contract Definition

Our confidential ERC20 contract inherits from Ownable2Step, which provides secure ownership management:

contract ConfidentialERC20 is Ownable2Step {

    // Contract implementation will go here

}

The Ownable2Step contract from OpenZeppelin sets the owner in the constructor, allowing only the owner to view all users’ balances.

​
State Variables

We need to define our state variables, including encrypted balances and allowances:

uint256 public _totalSupply;

string public _name;

string public _symbol;

uint8 public constant decimals = 18;



// Mappings for balances and allowances

mapping(address => euint256) internal balances;

mapping(address => mapping(address => euint256)) internal allowances;

mapping(uint256 => address) internal requestIdToUserAddress;

Notice that balances and allowances use the euint256 type for encrypted storage.

​
Events

Define the standard ERC20 events plus our custom decryption event:

// Events for Transfer, Approval, Mint, and Decryption

event Transfer(address indexed from, address indexed to);

event Approval(address indexed owner, address indexed spender);

event Mint(address indexed to, uint256 amount);

event UserBalanceDecrypted(address indexed user, uint256 decryptedAmount);

​
Understanding the Structure

Encrypted Types

euint256 is used for encrypted integers, ensuring balance privacy

Access Control

Ownable2Step provides secure ownership management

Events

Events enable tracking transfers and approvals without revealing amounts

​
Next Steps

Continue to learn how to implement the core token functionality

Was this page helpful?