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Import Required Libraries

First, we need to import the necessary contracts and libraries: 
pragma solidity ^0.8.28;

import {inco, e, ebool, euint256} from "@inco/lightning/src/Lib.sol";
import {asBool} from "@inco/lightning/src/shared/TypeUtils.sol";
import {DecryptionAttestation} from "@inco/lightning/src/lightning-parts/DecryptionAttester.types.sol";
import "@openzeppelin/contracts/access/Ownable2Step.sol";

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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.

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State Variables

We need to define our state variables, including encrypted balances and allowances: 
euint256 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;
Notice that balances, allowances, and totalSupply use the euint256 type for encrypted storage.

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Events

Define the standard ERC20 events plus custom events for minting: 
// Errors
error InsufficientFees();

// Events for Transfer, Approval, and Mint
event Transfer(address indexed from, address indexed to, euint256 amount);
event Approval(
    address indexed owner,
    address indexed spender,
    euint256 amount
);
event Mint(address indexed to, uint256 amount);
event EncryptedMint(address indexed to, euint256 amount);

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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

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Next Steps

Continue to learn how to implement the core token functionality