4. Deploying the contract

This guide walks you through deploying your Confidential ERC20 smart contract on the Sepolia test network.

Prerequisites

Before proceeding, ensure you have:

• A configured Hardhat project using the fhEVM Hardhat Template (see previous sections).

• A crypto wallet installed (e.g., Metamask).

• Some Sepolia ETH available for testing. If you don’t have enough ETH, use a Sepolia faucet to request free SepoliaETH for testing:

  • Alchemy Faucet

  • QuickNode Faucet

Step 1. Preparing for deployment

1. Generate a mnemonic seed for accounts using cast:

   • (cast is a Foundry function. If you don't have Foundry installed, run curl -L https://foundry.paradigm.xyz | bash first):

cast wallet new-mnemonic

1. Obtain a Sepolia RPC URL:

   • Sign up for a node provider such as Alchemy - https://www.alchemy.com/ or Infura - https://infura.io/. Copy your Sepolia RPC URL.

2. Open the .env file:

   • Past your mnemonic in the code:

     • MNEMONIC=<Your mnemonic generated>

   • Paste a Sepolia RPC URL:

     • SEPOLIA_RPC_URL=<Your node provider URL>

3. Verify generated accounts:

npx hardhat get-accounts --num-accounts 5

Step 2. Funding your wallet

1. Open your wallet (e.g, MetaMask)

2. Import the first 2 accounts (e.g., Alice and Bob) into your wallet with their private keys.

3. Fund these 2 accounts with some Sepolia ETH.

Step 3. Deploying the contract

In the deploy/ directory, there is a preconfigured deploy.ts file that handles the deployment process. You can customize it or add your own scripts.

To deploy the contracts to Sepolia, run:

# Using npm
npm run deploy-sepolia

# Using yarn
yarn deploy-sepolia

# Using pnpm
pnpm deploy-sepolia

Step 4. Verify the deployment

Once deployment is successful, you should see a console output that includes the contract address such as:

MyConfidentialERC20: 0x1234........ABCD

You can verify this contract on Sepolia Etherscan by searching for the deployed address.

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Congratulations! 🎉 You have deployed your first confidential ERC20 smart contract. Let's mint a few tokens and perform some encrypted transactions!