138 lines
2.7 KiB
JavaScript
138 lines
2.7 KiB
JavaScript
/*!
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* common.js - common functions for hd
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* Copyright (c) 2015-2016, Christopher Jeffrey (MIT License).
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* https://github.com/bcoin-org/bcoin
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*/
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'use strict';
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const assert = require('assert');
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const LRU = require('blru');
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const common = exports;
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/**
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* Index at which hardening begins.
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* @const {Number}
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* @default
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*/
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common.HARDENED = 0x80000000;
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/**
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* Min entropy bits.
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* @const {Number}
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* @default
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*/
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common.MIN_ENTROPY = 128;
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/**
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* Max entropy bits.
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* @const {Number}
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* @default
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*/
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common.MAX_ENTROPY = 512;
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/**
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* LRU cache to avoid deriving keys twice.
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* @type {LRU}
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*/
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common.cache = new LRU(500);
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/**
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* Parse a derivation path and return an array of indexes.
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* @see https://github.com/bitcoin/bips/blob/master/bip-0044.mediawiki
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* @param {String} path
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* @param {Boolean} hard
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* @returns {Number[]}
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*/
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common.parsePath = function parsePath(path, hard) {
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assert(typeof path === 'string');
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assert(typeof hard === 'boolean');
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assert(path.length >= 1);
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assert(path.length <= 3062);
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const parts = path.split('/');
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const root = parts[0];
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if (root !== 'm'
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&& root !== 'M'
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&& root !== 'm\''
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&& root !== 'M\'') {
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throw new Error('Invalid path root.');
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}
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const result = [];
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for (let i = 1; i < parts.length; i++) {
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let part = parts[i];
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const hardened = part[part.length - 1] === '\'';
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if (hardened)
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part = part.slice(0, -1);
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if (part.length > 10)
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throw new Error('Path index too large.');
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if (!/^\d+$/.test(part))
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throw new Error('Path index is non-numeric.');
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let index = parseInt(part, 10);
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if ((index >>> 0) !== index)
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throw new Error('Path index out of range.');
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if (hardened) {
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index |= common.HARDENED;
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index >>>= 0;
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}
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if (!hard && (index & common.HARDENED))
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throw new Error('Path index cannot be hardened.');
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result.push(index);
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}
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return result;
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};
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/**
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* Test whether the key is a master key.
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* @param {HDPrivateKey|HDPublicKey} key
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* @returns {Boolean}
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*/
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common.isMaster = function isMaster(key) {
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return key.depth === 0
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&& key.childIndex === 0
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&& key.parentFingerPrint === 0;
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};
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/**
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* Test whether the key is (most likely) a BIP44 account key.
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* @param {HDPrivateKey|HDPublicKey} key
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* @param {Number?} account
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* @returns {Boolean}
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*/
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common.isAccount = function isAccount(key, account) {
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if (account != null) {
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const index = (common.HARDENED | account) >>> 0;
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if (key.childIndex !== index)
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return false;
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}
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return key.depth === 3 && (key.childIndex & common.HARDENED) !== 0;
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};
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/**
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* A compressed pubkey of all zeroes.
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* @const {Buffer}
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* @default
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*/
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common.ZERO_KEY = Buffer.alloc(33, 0x00);
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