AutistMask/src/shared/wallet.js

// Wallet operations: mnemonic generation, HD derivation, signing.
// All crypto delegated to ethers.js.

const { Mnemonic, HDNodeWallet, Wallet } = require("ethers");
const { DEBUG, DEBUG_MNEMONIC, BIP44_ETH_PATH } = require("./constants");

function generateMnemonic() {
    if (DEBUG) return DEBUG_MNEMONIC;
    const m = Mnemonic.fromEntropy(
        globalThis.crypto.getRandomValues(new Uint8Array(16)),
    );
    return m.phrase;
}

function deriveAddressFromXpub(xpub, index) {
    const node = HDNodeWallet.fromExtendedKey(xpub);
    return node.deriveChild(index).address;
}

function hdWalletFromMnemonic(mnemonic) {
    const node = HDNodeWallet.fromPhrase(mnemonic, "", BIP44_ETH_PATH);
    const xpub = node.neuter().extendedKey;
    const firstAddress = node.deriveChild(0).address;
    return { xpub, firstAddress };
}

function addressFromPrivateKey(key) {
    const w = new Wallet(key);
    return w.address;
}

function getSignerForAddress(walletData, addrIndex, decryptedSecret) {
    if (walletData.type === "hd") {
        const node = HDNodeWallet.fromPhrase(
            decryptedSecret,
            "",
            BIP44_ETH_PATH,
        );
        return node.deriveChild(addrIndex);
    }
    return new Wallet(decryptedSecret);
}

function getPrivateKeyForAddress(walletData, addrIndex, decryptedSecret) {
    if (walletData.type === "hd") {
        const node = HDNodeWallet.fromPhrase(
            decryptedSecret,
            "",
            BIP44_ETH_PATH,
        );
        return node.deriveChild(addrIndex).privateKey;
    }
    return decryptedSecret;
}

function isValidMnemonic(mnemonic) {
    return Mnemonic.isValidMnemonic(mnemonic);
}

module.exports = {
    generateMnemonic,
    deriveAddressFromXpub,
    hdWalletFromMnemonic,
    addressFromPrivateKey,
    getSignerForAddress,
    getPrivateKeyForAddress,
    isValidMnemonic,
};