@polkadot/util-crypto/hd/ethereum/index.js

A collection of useful crypto utilities for @polkadot

import { bnToU8a, stringToU8a, u8aConcat } from '@polkadot/util';
import { BN_BE_32_OPTS } from '../../bn.js';
import { hmacShaAsU8a } from '../../hmac/index.js';
import { secp256k1PairFromSeed, secp256k1PrivateKeyTweakAdd } from '../../secp256k1/index.js';
import { HARDENED, hdValidatePath } from '../validatePath.js';
const MASTER_SECRET = stringToU8a('Bitcoin seed');
function createCoded(secretKey, chainCode) {
    return {
        chainCode,
        publicKey: secp256k1PairFromSeed(secretKey).publicKey,
        secretKey
    };
}
function deriveChild(hd, index) {
    const indexBuffer = bnToU8a(index, BN_BE_32_OPTS);
    const data = index >= HARDENED
        ? u8aConcat(new Uint8Array(1), hd.secretKey, indexBuffer)
        : u8aConcat(hd.publicKey, indexBuffer);
    try {
        const I = hmacShaAsU8a(hd.chainCode, data, 512);
        return createCoded(secp256k1PrivateKeyTweakAdd(hd.secretKey, I.slice(0, 32)), I.slice(32));
    }
    catch {
        // In case parse256(IL) >= n or ki == 0, proceed with the next value for i
        return deriveChild(hd, index + 1);
    }
}
export function hdEthereum(seed, path = '') {
    const I = hmacShaAsU8a(MASTER_SECRET, seed, 512);
    let hd = createCoded(I.slice(0, 32), I.slice(32));
    if (!path || path === 'm' || path === 'M' || path === "m'" || path === "M'") {
        return hd;
    }
    if (!hdValidatePath(path)) {
        throw new Error('Invalid derivation path');
    }
    const parts = path.split('/').slice(1);
    for (const p of parts) {
        hd = deriveChild(hd, parseInt(p, 10) + ((p.length > 1) && p.endsWith("'")
            ? HARDENED
            : 0));
    }
    return hd;
}