96 lines
2.3 KiB
JavaScript
96 lines
2.3 KiB
JavaScript
const ethUtils = require('ethereumjs-util');
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const randomBytes = require('randombytes');
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const ERRORS = {
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invalidHex: 'Invalid hex input'
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};
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/**
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* Create a wallet from a random private key
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* @returns {{address: string, privKey: string}}
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*/
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const getRandomWallet = () => {
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const randbytes = randomBytes(32);
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return {
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address: '0x' + ethUtils.privateToAddress(randbytes).toString('hex'),
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privKey: randbytes.toString('hex')
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};
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};
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/**
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* Check if a string is valid hexadecimal
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* @param hex
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* @returns {boolean}
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*/
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const isValidHex = hex => hex.length ? /^[0-9A-F]+$/g.test(hex.toUpperCase()) : true;
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/**
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* Check if a wallet respects the input constraints
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* @param wallet
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* @param input
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* @param isChecksum
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* @returns {boolean}
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*/
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const isValidVanityWallet = (wallet, input, isChecksum) => {
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if (!isChecksum) {
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return wallet.address.substr(2, input.length) === input;
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}
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const address = ethUtils.stripHexPrefix(wallet.address).toLowerCase();
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const hash = ethUtils.sha3(address).toString('hex');
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for (let i = 0; i < input.length; i++) {
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if (parseInt(hash[i], 16) >= 8) {
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if (address[i].toUpperCase() !== input[i]) {
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return false;
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}
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} else if (address[i] !== input[i]) {
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return false;
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}
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}
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return true;
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};
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const computeDifficulty = (pattern, isChecksum) => {
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const ret = Math.pow(16, pattern.length);
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return isChecksum ? (ret * Math.pow(2, pattern.replace(/[^a-f]/gi, '').length)) : ret;
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};
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const computeProbability = (difficulty, attempts) => {
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return 1 - Math.pow((difficulty - 1) / difficulty, attempts);
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};
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/**
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* Generate a lot of wallets until one satisfies the input constraints
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* @param input
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* @param isChecksum
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* @param max - Stop the generation after <max> attempts. Set to 0 for unlimited
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* @returns
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*/
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const getVanityWallet = (input, isChecksum, max) => {
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input = input || '';
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if (!isValidHex(input)) {
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throw new Error(ERRORS.invalidHex);
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}
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input = isChecksum ? input : input.toLowerCase();
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let _wallet = getRandomWallet();
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let attempts = 1;
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while (!isValidVanityWallet(_wallet, input, isChecksum)) {
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_wallet = getRandomWallet();
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attempts++;
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if (max && attempts >= max) {
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return null;
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}
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}
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_wallet.address = ethUtils.toChecksumAddress(_wallet.address);
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_wallet.attempts = attempts;
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return _wallet;
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};
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module.exports = {
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getVanityWallet,
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computeDifficulty,
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computeProbability,
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isValidHex
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};
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