ed25519-hd-key/dist/index.js

BIP-0032 like derivation for ed25519 curve

import { sha512 } from '@noble/hashes/sha2.js';
import { hmac } from '@noble/hashes/hmac.js';
import { concatBytes, hexToBytes } from '@noble/hashes/utils.js';
import * as ed from '@noble/ed25519';
import { replaceDerive, pathRegex } from './utils.js';
ed.hashes.sha512 = sha512;
const ED25519_CURVE = new TextEncoder().encode('ed25519 seed');
const HARDENED_OFFSET = 0x80000000;
export const getMasterKeyFromSeed = (seed) => {
    const I = hmac(sha512, ED25519_CURVE, hexToBytes(seed));
    const IL = I.slice(0, 32);
    const IR = I.slice(32);
    return {
        key: IL,
        chainCode: IR,
    };
};
export const CKDPriv = ({ key, chainCode }, index) => {
    const indexBuffer = new Uint8Array(4);
    const view = new DataView(indexBuffer.buffer);
    view.setUint32(0, index, false);
    const data = concatBytes(new Uint8Array([0]), key, indexBuffer);
    const I = hmac(sha512, chainCode, data);
    const IL = I.slice(0, 32);
    const IR = I.slice(32);
    return {
        key: IL,
        chainCode: IR,
    };
};
export const getPublicKey = (privateKey, withZeroByte = true) => {
    const { publicKey } = ed.keygen(privateKey);
    return withZeroByte ? concatBytes(new Uint8Array([0]), publicKey) : publicKey;
};
export const isValidPath = (path) => {
    if (!pathRegex.test(path)) {
        return false;
    }
    return !path
        .split('/')
        .slice(1)
        .map(replaceDerive)
        .some(isNaN);
};
export const derivePath = (path, seed, offset = HARDENED_OFFSET) => {
    if (!isValidPath(path)) {
        throw new Error('Invalid derivation path');
    }
    const { key, chainCode } = getMasterKeyFromSeed(seed);
    const segments = path
        .split('/')
        .slice(1)
        .map(replaceDerive)
        .map((el) => parseInt(el, 10));
    return segments.reduce((parentKeys, segment) => CKDPriv(parentKeys, segment + offset), {
        key,
        chainCode,
    });
};