How do you calculate a privatekey/public key from an xprv/pbub?

Question

I am trying to understand how HD wallets work in Ethereum. Currently I have managed to generate a child extended private and public key (xpub and xpriv) from my BIP32 Root Key. However, I can't find any documentation as to derive an Ethereum address/public/private key from my generated child xpbub and xpriv. Any is help is greatly appreciated !

Answer 1

Hope this script.js helps:

const Wallet = require('ethereumjs-wallet').default;

// Replace this with your child extended private key (xpriv)
const xpriv = 'xprv9s21ZrQH143K3QTDL4LXw2F7HEK3wJUD2nW2nRk4stbPy6cq3jPPqjiChkVvvNKmPGJxWUtg6LnF5kejMRNNU3TGtRBeJgk33yuGBxrMPHi';

// Initialize the wallet from the extended private key
const wallet = Wallet.fromExtendedPrivateKey(xpriv);

// Get the Ethereum address
const address = wallet.getAddressString();
console.log('Address:', address);

// Get the private key
const privateKey = wallet.getPrivateKeyString();
console.log('Private Key:', privateKey);

// Get the public key
const publicKey = wallet.getPublicKeyString();
console.log('Public Key:', publicKey);

NOTE: Make sure you installed ethereumjs-wallet library

npm install ethereumjs-wallet

After that you just run the script:

node ./path_to_script/script.js

You should get this output:

Address: 0x056db290f8ba3250ca64a45d16284d04bc6f5fbf
Private Key: 0xe8f32e723decf4051aefac8e2c93c9c5b214313817cdb01a1494b917c8436b35
Public Key: 0x39a36013301597daef41fbe593a02cc513d0b55527ec2df1050e2e8ff49c85c23cbe7ded0e7ce6a594896b8f62888fdbc5c8821305e2ea42bf01e37300116281