How to create private key from mnemonic and extra-word using web3

Question

In web3js, I can use below code to get private key and wallet address from mnemonic. But how can I get private key if user has mnemonic and extra-word from MEW

const ethers = require('ethers');
let mnemonicWallet = ethers.Wallet.fromMnemonic(mnemonic);

while creating wallet from myetherwallet's mnemonic method for wallet creation, there is option to choose extra word along with 12 or 24 words mnemonic. — murtza gondal, Jun 15 '20 at 06:41
Does this answer your question? How can I get a private key from a mnemonic phrase? — Masoud jt, Jun 15 '20 at 06:52
that is for mnemonic phrase only, I want to get private key when user has both mnemonic phrase and extra word. — murtza gondal, Jun 15 '20 at 06:53
By "extra-word" I believe the OP meant this https://kb.myetherwallet.com/en/security-and-privacy/mnemonic-phrase-extra-word/ from MyEtherWallet(MEW). The page does state that support for an extra word is very limited outside the MEW Platform — Stephen S, Jun 15 '20 at 08:07

score 3 · Answer 1 · answered Jun 15 '20 at 10:24

The "Extra Word" is a BIP-39 passphrase. It looks like you're using Ethers.js, so you can do something like this:

const { utils, Wallet } = require('ethers');

const hdNode = HDNode.fromMnemonic(mnemonic, passphrase).derivePath(utils.defaultPath);
const wallet = new Wallet(hdNode);

The fromMnemonic function does not provide a way to specify a passphrase directly, but this essentially does what fromMnemonic does with the extra passphrase.

How to create private key from mnemonic and extra-word using web3

1 Answers1