kennethhutw

pragma solidity ^0.5.0;

/*
 * @dev Provides information about the current execution context, including the
 * sender of the transaction and its data. While these are generally available
 * via msg.sender and msg.data, they should not be accessed in such a direct
 * manner, since when dealing with GSN meta-transactions the account sending and
 * paying for execution may not be the actual sender (as far as an application
 * is concerned).
 *

kennethhutw

window.addEventListener("load", function() {
  if (window.ethereum) {
    // use MetaMask's provider
    App.web3 = new Web3(window.ethereum);
    window.ethereum.enable(); // get permission to access accounts

    // detect Metamask account change
    window.ethereum.on('accountsChanged', function (accounts) {
      console.log('accountsChanges',accounts);

kennethhutw

pragma solidity ^0.5.0;

// METADATA 是每一個token 都有不同的metadata

// import "openzeppelin-solidity/contracts/token/ERC721/ERC721Full.sol";
import "https://github.com/OpenZeppelin/openzeppelin-contracts/blob/v2.5.0/contracts/drafts/Counters.sol";

// ERC721Full
import "https://github.com/OpenZeppelin/openzeppelin-contracts/blob/v2.5.0/contracts/token/ERC721/ERC721.sol";
import "https://github.com/OpenZeppelin/openzeppelin-contracts/blob/v2.5.0/contracts/token/ERC721/ERC721Enumerable.sol";

kennethhutw

import React, { Component } from 'react';
import { Text } from 'react-native';
import { DrawerNavigator } from 'react-navigation';

const ContentScreen = ({ navigation }) => (
  <Text>Content Hello World</Text>
);

const LeftDrawerScreen = ({ navigation }) => (
  <Text>Left Drawer</Text>

kennethhutw

const fs = require("fs")
let BITBOX = require('bitbox-sdk').BITBOX;
let bitbox = new BITBOX();
var mnemonic = bitbox.Mnemonic.generate()

const NETWORK = `mainnet`;

const filetime = new Date().getTime();
console.log("mnemonic",mnemonic);

kennethhutw

using System;
using System.Text;
using Nethereum.Hex.HexConvertors.Extensions;
using Nethereum.Signer;
using Nethereum.Util;
using Nethereum.Signer.Crypto;

class ECDSASecp256k1Example
{
    static void Main()

kennethhutw

import Web3 from 'web3';

if (window.ethereum) {
  window.web3 = new Web3(ethereum);
  try {
    // Request account access if needed
    ethereum.enable();
  } catch (error) {
    // User denied account access...
  }

kennethhutw

var Web3 = require('web3');
var web3 = new Web3();
var message = "Hello, I am Kenneth!";

console.log("version :", web3.version);

var signature = web3.eth.accounts.sign(message, '0xb5b1870957d373ef0eeffecc6e4812c0fd08f554b37b233526acc331bf1544f7');

console.log("signature :", signature);

kennethhutw

var ethUtil = require('ethereumjs-util');

var data = 'Login';
var message = ethUtil.toBuffer(data);
var msgHash = ethUtil.hashPersonalMessage(message);

var privateKey = new Buffer('62debf78d596673bce224a85a90da5aecf6e781d9aadcaedd4f65586cfe670d2', "hex")
var sig = ethUtil.ecsign(msgHash, privateKey);

var signature = ethUtil.toBuffer(sig)

kennethhutw

const sigUtil = require('eth-sig-util');
var messageHashx = new Buffer(delegationHash)
const msgParams = { data: messageHashx }
const _signature = sigUtil.personalSign(new Buffer(tokenholder.pk, "hex"),msgParams);

console.log("_signature", _signature);
msgParams.sig = _signature
console.log("recovered address ",sigUtil.recoverPersonalSignature(msgParams));
 
delegatedTransferOperator.methods.recover(delegationHash, _signature).call((error, result) => {