Implement RedirectionTransactionFactory

The factory can create, sign, and finalize the redirection transaction.

core/src/main/java/bisq/core/btc/wallet/RedirectionTransactionFactory.java

@@ -0,0 +1,133 @@
+/*
+ * This file is part of Bisq.
+ *
+ * Bisq is free software: you can redistribute it and/or modify it
+ * under the terms of the GNU Affero General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or (at
+ * your option) any later version.
+ *
+ * Bisq is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU Affero General Public
+ * License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with Bisq. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+package bisq.core.btc.wallet;
+
+import bisq.core.btc.exceptions.TransactionVerificationException;
+
+import bisq.common.util.Tuple2;
+
+import org.bitcoinj.core.Address;
+import org.bitcoinj.core.AddressFormatException;
+import org.bitcoinj.core.Coin;
+import org.bitcoinj.core.ECKey;
+import org.bitcoinj.core.NetworkParameters;
+import org.bitcoinj.core.Sha256Hash;
+import org.bitcoinj.core.SignatureDecodeException;
+import org.bitcoinj.core.Transaction;
+import org.bitcoinj.core.TransactionInput;
+import org.bitcoinj.core.TransactionOutput;
+import org.bitcoinj.core.TransactionWitness;
+import org.bitcoinj.crypto.DeterministicKey;
+import org.bitcoinj.crypto.TransactionSignature;
+import org.bitcoinj.script.Script;
+import org.bitcoinj.script.ScriptBuilder;
+
+import org.bouncycastle.crypto.params.KeyParameter;
+
+import java.util.List;
+
+import static com.google.common.base.Preconditions.checkArgument;
+import static com.google.common.base.Preconditions.checkNotNull;
+
+public class RedirectionTransactionFactory {
+
+    private final NetworkParameters params;
+
+    public RedirectionTransactionFactory(NetworkParameters params) {
+        this.params = params;
+    }
+
+    public Transaction createUnsignedRedirectionTransaction(Transaction warningTx,
+                                                            List<Tuple2<Long, String>> receivers,
+                                                            Tuple2<Long, String> feeBumpOutputAmountAndAddress)
+            throws AddressFormatException, TransactionVerificationException {
+
+        TransactionOutput warningTxOutput = warningTx.getOutput(0);
+
+        Transaction redirectionTx = new Transaction(params);
+        redirectionTx.addInput(warningTxOutput);
+
+        checkArgument(!receivers.isEmpty(), "receivers must not be empty");
+        receivers.forEach(receiver -> redirectionTx.addOutput(Coin.valueOf(receiver.first), Address.fromString(params, receiver.second)));
+
+        redirectionTx.addOutput(
+                Coin.valueOf(feeBumpOutputAmountAndAddress.first),
+                Address.fromString(params, feeBumpOutputAmountAndAddress.second)
+        );
+
+        WalletService.printTx("Unsigned redirectionTx", redirectionTx);
+        WalletService.verifyTransaction(redirectionTx);
+
+        return redirectionTx;
+    }
+
+    public byte[] signRedirectionTransaction(Transaction redirectionTx,
+                                             Transaction warningTx,
+                                             DeterministicKey myMultiSigKeyPair,
+                                             KeyParameter aesKey)
+            throws AddressFormatException, TransactionVerificationException {
+
+        TransactionOutput warningTxPayoutOutput = warningTx.getOutput(0);
+        Script redeemScript = warningTxPayoutOutput.getScriptPubKey();
+        Coin redirectionTxInputValue = warningTxPayoutOutput.getValue();
+
+        Sha256Hash sigHash = redirectionTx.hashForWitnessSignature(0, redeemScript,
+                redirectionTxInputValue, Transaction.SigHash.ALL, false);
+
+        checkNotNull(myMultiSigKeyPair, "myMultiSigKeyPair must not be null");
+        if (myMultiSigKeyPair.isEncrypted()) {
+            checkNotNull(aesKey);
+        }
+
+        ECKey.ECDSASignature mySignature = myMultiSigKeyPair.sign(sigHash, aesKey).toCanonicalised();
+        WalletService.printTx("redirectionTx for sig creation", redirectionTx);
+        WalletService.verifyTransaction(redirectionTx);
+        return mySignature.encodeToDER();
+    }
+
+    public Transaction finalizeRedirectionTransaction(Transaction warningTx,
+                                                      Transaction redirectionTx,
+                                                      byte[] buyerSignature,
+                                                      byte[] sellerSignature,
+                                                      Coin inputValue)
+            throws AddressFormatException, TransactionVerificationException {
+
+        TransactionInput input = redirectionTx.getInput(0);
+        input.setScriptSig(ScriptBuilder.createEmpty());
+
+        Script redeemScript = createRedeemScript(buyerSignature, sellerSignature);
+        TransactionWitness witness = TransactionWitness.redeemP2WSH(redeemScript);
+        input.setWitness(witness);
+
+        WalletService.printTx("finalizeRedirectionTransaction", redirectionTx);
+        WalletService.verifyTransaction(redirectionTx);
+
+        Script scriptPubKey = warningTx.getOutput(0).getScriptPubKey();
+        input.getScriptSig().correctlySpends(redirectionTx, 0, witness, inputValue, scriptPubKey, Script.ALL_VERIFY_FLAGS);
+        return redirectionTx;
+    }
+
+    private Script createRedeemScript(byte[] buyerSignature, byte[] sellerSignature) {
+        return new ScriptBuilder()
+                .number(0)
+                .data(buyerSignature)
+                .data(sellerSignature)
+                .number(1)
+                .build();
+    }
+}

core/src/main/java/bisq/core/btc/wallet/TradeWalletService.java

@@ -83,6 +83,7 @@ public class TradeWalletService {
     private final NetworkParameters params;
 
     private final WarningTransactionFactory warningTransactionFactory;
+    private final RedirectionTransactionFactory redirectionTransactionFactory;
 
     @Nullable
     private Wallet wallet;
@@ -102,6 +103,7 @@ public TradeWalletService(WalletsSetup walletsSetup, Preferences preferences) {
         this.preferences = preferences;
         this.params = Config.baseCurrencyNetworkParameters();
         this.warningTransactionFactory = new WarningTransactionFactory(params);
+        this.redirectionTransactionFactory = new RedirectionTransactionFactory(params);
         walletsSetup.addSetupCompletedHandler(() -> {
             walletConfig = walletsSetup.getWalletConfig();
             wallet = walletsSetup.getBtcWallet();
@@ -856,6 +858,49 @@ public Transaction finalizeWarningTx(Transaction warningTx,
         );
     }
 
+    ///////////////////////////////////////////////////////////////////////////////////////////
+    // Redirection tx
+    ///////////////////////////////////////////////////////////////////////////////////////////
+
+    public Transaction createUnsignedRedirectionTx(Transaction warningTx,
+                                                   List<Tuple2<Long, String>> receivers,
+                                                   Tuple2<Long, String> feeBumpOutputAmountAndAddress)
+            throws AddressFormatException, TransactionVerificationException {
+        return redirectionTransactionFactory.createUnsignedRedirectionTransaction(
+                warningTx,
+                receivers,
+                feeBumpOutputAmountAndAddress
+        );
+    }
+
+    public byte[] signRedirectionTx(Transaction redirectionTx,
+                                    Transaction warningTx,
+                                    DeterministicKey myMultiSigKeyPair,
+                                    KeyParameter aesKey)
+            throws AddressFormatException, TransactionVerificationException {
+        return redirectionTransactionFactory.signRedirectionTransaction(
+                redirectionTx,
+                warningTx,
+                myMultiSigKeyPair,
+                aesKey
+        );
+    }
+
+    public Transaction finalizeRedirectionTx(Transaction warningTx,
+                                             Transaction redirectionTx,
+                                             byte[] buyerSignature,
+                                             byte[] sellerSignature,
+                                             Coin inputValue)
+            throws AddressFormatException, TransactionVerificationException, SignatureDecodeException {
+        return redirectionTransactionFactory.finalizeRedirectionTransaction(
+                warningTx,
+                redirectionTx,
+                buyerSignature,
+                sellerSignature,
+                inputValue
+        );
+    }
+
     ///////////////////////////////////////////////////////////////////////////////////////////
     // Standard payout tx
     ///////////////////////////////////////////////////////////////////////////////////////////