package one.wangwei.blockchain.transaction;
import lombok.AllArgsConstructor;
import lombok.Data;
import lombok.NoArgsConstructor;
import lombok.extern.slf4j.Slf4j;
import one.wangwei.blockchain.block.Blockchain;
import one.wangwei.blockchain.util.BtcAddressUtils;
import one.wangwei.blockchain.util.SerializeUtils;
import one.wangwei.blockchain.wallet.Wallet;
import one.wangwei.blockchain.wallet.WalletUtils;
import org.apache.commons.codec.binary.Hex;
import org.apache.commons.codec.digest.DigestUtils;
import org.apache.commons.lang3.ArrayUtils;
import org.apache.commons.lang3.StringUtils;
import org.bouncycastle.jcajce.provider.asymmetric.ec.BCECPrivateKey;
import org.bouncycastle.jce.ECNamedCurveTable;
import org.bouncycastle.jce.provider.BouncyCastleProvider;
import org.bouncycastle.jce.spec.ECParameterSpec;
import org.bouncycastle.jce.spec.ECPublicKeySpec;
import org.bouncycastle.math.ec.ECPoint;
import java.math.BigInteger;
import java.security.KeyFactory;
import java.security.PublicKey;
import java.security.Security;
import java.security.Signature;
import java.util.Arrays;
import java.util.Iterator;
import java.util.Map;
/**
* 交易
*
* @author wangwei
* @date 2017/03/04
*/
@Data
@AllArgsConstructor
@NoArgsConstructor
@Slf4j
public class Transaction {
private static final int SUBSIDY = 10;
/**
* 交易的Hash
*/
private byte[] txId;
/**
* 交易输入
*/
private TXInput[] inputs;
/**
* 交易输出
*/
private TXOutput[] outputs;
/**
* 创建日期
*/
private long createTime;
/**
* 计算交易信息的Hash值
*
* @return
*/
public byte[] hash() {
// 使用序列化的方式对Transaction对象进行深度复制
byte[] serializeBytes = SerializeUtils.serialize(this);
Transaction copyTx = (Transaction) SerializeUtils.deserialize(serializeBytes);
copyTx.setTxId(new byte[]{});
return DigestUtils.sha256(SerializeUtils.serialize(copyTx));
}
/**
* 创建CoinBase交易
*
* @param to 收账的钱包地址
* @param data 解锁脚本数据
* @return
*/
public static Transaction newCoinbaseTX(String to, String data) {
if (StringUtils.isBlank(data)) {
data = String.format("Reward to '%s'", to);
}
// 创建交易输入
TXInput txInput = new TXInput(new byte[]{}, -1, null, data.getBytes());
// 创建交易输出
TXOutput txOutput = TXOutput.newTXOutput(SUBSIDY, to);
// 创建交易
Transaction tx = new Transaction(null, new TXInput[]{txInput},
new TXOutput[]{txOutput}, System.currentTimeMillis());
// 设置交易ID
tx.setTxId(tx.hash());
return tx;
}
/**
* 是否为 Coinbase 交易
*
* @return
*/
public boolean isCoinbase() {
return this.getInputs().length == 1
&& this.getInputs()[0].getTxId().length == 0
&& this.getInputs()[0].getTxOutputIndex() == -1;
}
/**
* 从 from 向 to 支付一定的 amount 的金额
*
* @param from 支付钱包地址
* @param to 收款钱包地址
* @param amount 交易金额
* @param blockchain 区块链
* @return
*/
public static Transaction newUTXOTransaction(String from, String to, int amount, Blockchain blockchain) throws Exception {
// 获取钱包
Wallet senderWallet = WalletUtils.getInstance().getWallet(from);
byte[] pubKey = senderWallet.getPublicKey();
byte[] pubKeyHash = BtcAddressUtils.ripeMD160Hash(pubKey);
SpendableOutputResult result = new UTXOSet(blockchain).findSpendableOutputs(pubKeyHash, amount);
int accumulated = result.getAccumulated();
Map<String, int[]> unspentOuts = result.getUnspentOuts();
if (accumulated < amount) {
log.error("ERROR: Not enough funds ! accumulated=" + accumulated + ", amount=" + amount);
throw new RuntimeException("ERROR: Not enough funds ! ");
}
Iterator<Map.Entry<String, int[]>> iterator = unspentOuts.entrySet().iterator();
TXInput[] txInputs = {};
while (iterator.hasNext()) {
Map.Entry<String, int[]> entry = iterator.next();
String txIdStr = entry.getKey();
int[] outIds = entry.getValue();
byte[] txId = Hex.decodeHex(txIdStr);
for (int outIndex : outIds) {
txInputs = ArrayUtils.add(txInputs, new TXInput(txId, outIndex, null, pubKey));
}
}
TXOutput[] txOutput = {};
txOutput = ArrayUtils.add(txOutput, TXOutput.newTXOutput(amount, to));
if (accumulated > amount) {
txOutput = ArrayUtils.add(txOutput, TXOutput.newTXOutput((accumulated - amount), from));
}
Transaction newTx = new Transaction(null, txInputs, txOutput, System.currentTimeMillis());
newTx.setTxId(newTx.hash());
// 进行交易签名
blockchain.signTransaction(newTx, senderWallet.getPrivateKey());
return newTx;
}
/**
* 创建用于签名的交易数据副本，交易输入的 signature 和 pubKey 需要设置为null
*
* @return
*/
public Transaction trimmedCopy() {
TXInput[] tmpTXInputs = new TXInput[this.getInputs().length];
for (int i = 0; i < this.getInputs().length; i++) {
TXInput txInput = this.getInputs()[i];
tmpTXInputs[i] = new TXInput(txInput.getTxId(), txInput.getTxOutputIndex(), null, null);
}
TXOutput[] tmpTXOutputs = new TXOutput[this.getOutputs().length];
for (int i = 0; i < this.getOutputs().length; i++) {
TXOutput txOutput = this.getOutputs()[i];
tmpTXOutputs[i] = new TXOutput(txOutput.getValue(), txOutput.getPubKeyHash());
}
return new Transaction(this.getTxId(), tmpTXInputs, tmpTXOutputs, this.getCreateTime());
}
/**
* 签名
*
* @param privateKey 私钥
* @param prevTxMap 前面多笔交易集合
*/
public void sign(BCECPrivateKey privateKey, Map<String, Transaction> prevTxMap) throws Exception {
// coinbase 交易信息不需要签名，因为它不存在交易输入信息
if (this.isCoinbase()) {
return;
}
// 再次验证一下交易信息中的交易输入是否正确，也就是能否查找对应的交易数据
for (TXInput txInput : this.getInputs()) {
if (prevTxMap.get(Hex.encodeHexString(txInput.getTxId())) == null) {
throw new RuntimeException("ERROR: Previous transaction is not correct");
}
}
// 创建用于签名的交易信息的副本
Transaction txCopy = this.trimmedCopy();
Security.addProvider(new BouncyCastleProvider());
Signature ecdsaSign = Signature.getInstance("SHA256withECDSA", BouncyCastleProvider.PROVIDER_NAME);
ecdsaSign.initSign(privateKey);
for (int i = 0; i < txCopy.getInputs().length; i++) {
TXInput txInputCopy = txCopy.getInputs()[i];
// 获取交易输入TxID对应的交易数据
Transaction prevTx = prevTxMap.get(Hex.encodeHexString(txInputCopy.getTxId()));
// 获取交易输入所对应的上一笔交易中的交易输出
TXOutput prevTxOutput = prevTx.getOutputs()[txInputCopy.getTxOutputIndex()];
txInputCopy.setPubKey(prevTxOutput.getPubKeyHash());
txInputCopy.setSignature(null);
// 得到要签名的数据，即交易ID
txCopy.setTxId(txCopy.hash());
txInputCopy.setPubKey(null);
// 对整个交易信息仅进行签名，即对交易ID进行签名
ecdsaSign.update(txCopy.getTxId());
byte[] signature = ecdsaSign.sign();
// 将整个交易数据的签名赋值给交易输入，因为交易输入需要包含整个交易信息的签名
// 注意是将得到的签名赋值给原交易信息中的交易输入
this.getInputs()[i].setSignature(signature);
}
}
/**
* 验证交易信息
*
* @param prevTxMap 前面多笔交易集合
* @return
*/
public boolean verify(Map<String, Transaction> prevTxMap) throws Exception {
// coinbase 交易信息不需要签名，也就无需验证
if (this.isCoinbase()) {
return true;
}
// 再次验证一下交易信息中的交易输入是否正确，也就是能否查找对应的交易数据
for (TXInput txInput : this.getInputs()) {
if (prevTxMap.get(Hex.encodeHexString(txInput.getTxId())) == null) {
throw new RuntimeException("ERROR: Previous transaction is not correct");
}
}
// 创建用于签名验证的交易信息的副本
Transaction txCopy = this.trimmedCopy();
Security.addProvider(new BouncyCastleProvider());
ECParameterSpec ecParameters = ECNamedCurveTable.getParameterSpec("secp256k1");
KeyFactory keyFactory = KeyFactory.getInstance("ECDSA", BouncyCastleProvider.PROVIDER_NAME);
Signature ecdsaVerify = Signature.getInstance("SHA256withECDSA", BouncyCastleProvider.PROVIDER_NAME);
for (int i = 0; i < this.getInputs().length; i++) {
TXInput txInput = this.getInputs()[i];
// 获取交易输入TxID对应的交易数据
Transaction prevTx = prevTxMap.get(Hex.encodeHexString(txInput.getTxId()));
// 获取交易输入所对应的上一笔交易中的交易输出
TXOutput prevTxOutput = prevTx.getOutputs()[txInput.getTxOutputIndex()];
TXInput txInputCopy = txCopy.getInputs()[i];
txInputCopy.setSignature(null);
txInputCopy.setPubKey(prevTxOutput.getPubKeyHash());
// 得到要签名的数据，即交易ID
txCopy.setTxId(txCopy.hash());
txInputCopy.setPubKey(null);
// 使用椭圆曲线 x,y 点去生成公钥Key
BigInteger x = new BigInteger(1, Arrays.copyOfRange(txInput.getPubKey(), 1, 33));
BigInteger y = new BigInteger(1, Arrays.copyOfRange(txInput.getPubKey(), 33, 65));
ECPoint ecPoint = ecParameters.getCurve().createPoint(x, y);
ECPublicKeySpec keySpec = new ECPublicKeySpec(ecPoint, ecParameters);
PublicKey publicKey = keyFactory.generatePublic(keySpec);
ecdsaVerify.initVerify(publicKey);
ecdsaVerify.update(txCopy.getTxId());
if (!ecdsaVerify.verify(txInput.getSignature())) {
return false;
}
}
return true;
}
}
