KIPU Bank module 2

KipuBank is a simple, secure ETH vault smart contract that allows each user to deposit and withdraw ETH into their own "personal vault" with:

• Global bank capacity limit (bankCap)
• Custom errors for gas-efficient reverts
• Event logging for deposits & withdrawals
• Reentrancy protection and CEI pattern

---

Overview

Function	Type	Description
deposit()	external payable	Deposit ETH into your vault
withdraw(uint256 amount)	external	Withdraw ETH up to your vault balance and the max withdraw limit
getBalance(address user)	external view	View any user's vault balance
totalBankBalance()	external view	View total ETH held by the bank
_transferETH()	private	transfer eth securely

---

Práticas de Segurança a Seguir:

Use Custom errors instead require for save gas.

Respect checks-effects-interactions patterns and global naming conventions.

Readable.

Well comment.

Options for deployment: via Remix IDE (quick/manual) or via Hardhat (scripted/automated).

---

Option 1 — Deploy with Remix IDE

1. Open Remix IDE.
2. Create a new file deploy.ts and paste:

// Remix Script Deployment
async function deploy() {
  const KipuBank = await ethers.getContractFactory("KipuBank");
  const kipuBank = await KipuBank.deploy(
    ethers.parseEther("100"), // bankCap: change this as needed
    ethers.parseEther("1")    // maxWithdrawPerTx: change this as needed
  );

  console.log("✅ KipuBank deployed to:", kipuBank.target);
}

deploy();

---

Option 2 — Deploy with Hardhat

npm install

import { ethers } from "hardhat";

async function main() {
  const BANK_CAP = ethers.utils.parseEther("1000"); // global cap
  const MAX_WITHDRAW = ethers.utils.parseEther("1"); // per-tx limit

  const Kipu = await ethers.getContractFactory("KipuBank");
  const kipu = await Kipu.deploy(BANK_CAP, MAX_WITHDRAW);
  await kipu.deployed();

  console.log("✅ KipuBank deployed to:", kipu.address);
}

main().catch((e) => {
  console.error(e);
  process.exit(1);
});

npx hardhat run scripts/deploy.ts --network sepolia

npx hardhat verify --network sepolia <DEPLOYED_ADDRESS> 1000000000000000000000 1000000000000000000

Testing

If you use Remix:

Use the "Deploy & Run" tab to call deposit();

Call withdraw(amount) to test withdrawals (must be ≤ MAX_WITHDRAW_PER_TX).
npx hardhat test