Java tutorial
/* * Copyright (c) 2016 Andrew Chow * * This software may be modified and distributed under the terms * of the MIT License. See the LICENSE file for details. */ package com.achow101.bittipaddr.server; import com.achow101.bittipaddr.shared.AddrReq; import com.amazonaws.services.dynamodbv2.AmazonDynamoDBClient; import com.amazonaws.services.dynamodbv2.document.DynamoDB; import com.amazonaws.services.dynamodbv2.document.Item; import com.amazonaws.services.dynamodbv2.document.Table; import com.amazonaws.services.dynamodbv2.document.spec.UpdateItemSpec; import com.amazonaws.services.dynamodbv2.document.utils.ValueMap; import com.google.gwt.user.server.rpc.RemoteServiceServlet; import com.achow101.bittipaddr.client.bittipaddrService; import com.mysql.fabric.xmlrpc.base.Array; import org.bitcoinj.core.Address; import org.bitcoinj.core.AddressFormatException; import org.bitcoinj.core.NetworkParameters; import org.bitcoinj.core.WrongNetworkException; import org.bitcoinj.crypto.DeterministicKey; import org.bitcoinj.crypto.HDKeyDerivation; import org.bitcoinj.params.MainNetParams; import org.bitcoinj.wallet.UnreadableWalletException; import java.io.UnsupportedEncodingException; import java.math.BigInteger; import java.security.MessageDigest; import java.security.NoSuchAlgorithmException; import java.security.SecureRandom; import java.util.Arrays; public class bittipaddrServiceImpl extends RemoteServiceServlet implements bittipaddrService { private NetworkParameters params = MainNetParams.get(); private SecureRandom random = new SecureRandom(); public String addAddresses(AddrReq req) { // Setup the aws dynamo db client AmazonDynamoDBClient client = new AmazonDynamoDBClient(); DynamoDB dynamoDB = new DynamoDB(client); Table table = dynamoDB.getTable("Bittipaddrs"); // Check that the request is for editing an existing one if (!req.getId().equals("NEW")) { try { Item item = table.getItem("ID", req.getId()); // Check the password if (getHash(req.getPassword()).equals(item.getString("passhash"))) { // If the req has been edited, update DB if (req.isEdited()) { // Recalculate addresses if xpub is set if (!req.getXpub().equals("NONE")) { try { // Check Xpub DeterministicKey xpub = DeterministicKey.deserializeB58(req.getXpub(), params); DeterministicKey external = HDKeyDerivation.deriveChildKey(xpub, 0); // Derive 1000 addresses and add to req String[] addrs = new String[1000]; for (int i = 0; i < 1000; i++) { addrs[i] = HDKeyDerivation.deriveChildKey(external, i).toAddress(params) .toBase58(); } req.setAddresses(addrs); } catch (Exception e) { return "<p style=\"color:red;\">Invalid xpub" + req.getXpub() + "</p>"; } } if (req.getAddresses()[0].isEmpty()) return "<p style=\"color:red;\">Must have at least one address</p>"; UpdateItemSpec updateItemSpec = new UpdateItemSpec().withPrimaryKey("ID", req.getId()) .withUpdateExpression("set AddrIndex=:i, Addresses=:a, bip32xpub=:x") .withValueMap(new ValueMap().withNumber(":i", 0) .withList(":a", Arrays.asList(req.getAddresses())) .withString(":x", req.getXpub())); table.updateItem(updateItemSpec); return req.getHtml(); } String[] addresses = new String[item.getList("Addresses").size()]; item.getList("Addresses").toArray(addresses); req.setAddresses(addresses); req.setXpub(item.getString("bip32xpub")); if (req.isEditable()) return req.getPlain(); else return req.getHtml(); } else return "<p style=\"color:red;\">Incorrect password</p>"; } catch (Exception e) { return "<p style=\"color:red;\">Could not find unit</p>"; } } // Check validity of addresses else if (req.getXpub().equals("NONE") && req.getAddresses().length != 0) { for (int i = 0; i < req.getAddresses().length; i++) { try { Address addr = Address.fromBase58(params, req.getAddresses()[i]); } catch (AddressFormatException e) { return "<p style=\"color:red;\">Invalid address" + req.getAddresses()[i] + "</p>"; } } } // Check validity of xpub else if (!req.getXpub().equals("NONE") && req.getAddresses().length == 0) { try { // Check Xpub DeterministicKey xpub = DeterministicKey.deserializeB58(req.getXpub(), params); DeterministicKey external = HDKeyDerivation.deriveChildKey(xpub, 0); // Derive 1000 addresses and add to req String[] addrs = new String[1000]; for (int i = 0; i < 1000; i++) { addrs[i] = HDKeyDerivation.deriveChildKey(external, i).toAddress(params).toBase58(); } req.setAddresses(addrs); } catch (Exception e) { return "<p style=\"color:red;\">Invalid xpub" + req.getXpub() + "</p>"; } } // Set the request ID and unique password req.setId(new BigInteger(40, random).toString(32)); req.setPassword(new BigInteger(256, random).toString(32)); // Add request to DynamoDB Item item = null; try { item = new Item().withPrimaryKey("ID", req.getId()).withInt("AddrIndex", 0) .withList("Addresses", Arrays.asList(req.getAddresses())).withString("bip32xpub", req.getXpub()) .withString("passhash", getHash(req.getPassword())); } catch (NoSuchAlgorithmException e) { e.printStackTrace(); } catch (UnsupportedEncodingException e) { e.printStackTrace(); } table.putItem(item); return req.getHtml(); } private String getHash(String pass) throws NoSuchAlgorithmException, UnsupportedEncodingException { MessageDigest md = MessageDigest.getInstance("SHA-256"); md.update(pass.getBytes("UTF-8")); byte[] digest = md.digest(); return String.format("%064x", new java.math.BigInteger(1, digest)); } }