near-hd-key/dist/index.js

BIP-0032 like derivation for ed25519 curve

"use strict";
Object.defineProperty(exports, "__esModule", { value: true });
exports.derivePath = exports.isValidPath = exports.getPublicKey = exports.getMasterKeyFromSeed = void 0;
const createHmac = require("create-hmac");
const nacl = require("tweetnacl");
const utils_1 = require("./utils");
const ED25519_CURVE = 'ed25519 seed';
const HARDENED_OFFSET = 0x80000000;
exports.getMasterKeyFromSeed = (seed) => {
    const hmac = createHmac('sha512', ED25519_CURVE);
    const I = hmac.update(Buffer.from(seed, 'hex')).digest();
    const IL = I.slice(0, 32);
    const IR = I.slice(32);
    return {
        key: IL,
        chainCode: IR,
    };
};
const CKDPriv = ({ key, chainCode }, index) => {
    const indexBuffer = Buffer.allocUnsafe(4);
    indexBuffer.writeUInt32BE(index, 0);
    const data = Buffer.concat([Buffer.alloc(1, 0), key, indexBuffer]);
    const I = createHmac('sha512', chainCode)
        .update(data)
        .digest();
    const IL = I.slice(0, 32);
    const IR = I.slice(32);
    return {
        key: IL,
        chainCode: IR,
    };
};
exports.getPublicKey = (privateKey, withZeroByte = true) => {
    const keyPair = nacl.sign.keyPair.fromSeed(privateKey);
    const signPk = keyPair.secretKey.subarray(32);
    const zero = Buffer.alloc(1, 0);
    return withZeroByte ?
        Buffer.concat([zero, Buffer.from(signPk)]) :
        Buffer.from(signPk);
};
exports.isValidPath = (path) => {
    if (!utils_1.pathRegex.test(path)) {
        return false;
    }
    return !path
        .split('/')
        .slice(1)
        .map(utils_1.replaceDerive)
        .some(isNaN);
};
exports.derivePath = (path, seed, offset = HARDENED_OFFSET) => {
    if (!exports.isValidPath(path)) {
        throw new Error('Invalid derivation path');
    }
    const { key, chainCode } = exports.getMasterKeyFromSeed(seed);
    const segments = path
        .split('/')
        .slice(1)
        .map(utils_1.replaceDerive)
        .map(el => parseInt(el, 10));
    return segments.reduce((parentKeys, segment) => CKDPriv(parentKeys, segment + offset), { key, chainCode });
};