143 lines
2.7 KiB
JavaScript
143 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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var LRU = require('../utils/lru');
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var 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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* Max index (u32max + 1).
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* @const {Number}
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* @default
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*/
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common.MAX_INDEX = 0x100000000;
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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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* Seed salt for key derivation ("Bitcoin seed").
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* @const {Buffer}
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* @default
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*/
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common.SEED_SALT = Buffer.from('Bitcoin seed', 'ascii');
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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 {Number?} max - Max index.
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* @returns {Number[]}
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*/
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common.parsePath = function parsePath(path, max) {
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var parts = path.split('/');
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var root = parts.shift();
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var result = [];
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var i, hardened, index;
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if (max == null)
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max = common.MAX_INDEX;
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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('Bad path root.');
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}
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for (i = 0; i < parts.length; i++) {
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index = parts[i];
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hardened = index[index.length - 1] === '\'';
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if (hardened)
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index = index.slice(0, -1);
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if (!/^\d+$/.test(index))
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throw new Error('Non-number path index.');
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index = parseInt(index, 10);
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if (hardened)
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index += common.HARDENED;
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if (!(index >= 0 && index < max))
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throw new Error('Index out of range.');
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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.readUInt32LE(0, true) === 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?} accountIndex
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* @returns {Boolean}
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*/
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common.isAccount44 = function isAccount44(key, accountIndex) {
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if (accountIndex != null) {
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if (key.childIndex !== common.HARDENED + accountIndex)
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return false;
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}
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return key.depth === 3 && key.childIndex >= common.HARDENED;
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};
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/**
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* Test whether the key is a BIP45 purpose key.
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* @param {HDPrivateKey|HDPublicKey} key
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* @returns {Boolean}
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*/
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common.isPurpose45 = function isPurpose45(key) {
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return key.depth === 1 && key.childIndex === common.HARDENED + 45;
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};
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