Implement ClaimTransactionFactory

The factory creates, signs, and finalizes the claim transaction.

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

@@ -0,0 +1,129 @@
+/*
+ * 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 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.Transaction;
+import org.bitcoinj.core.TransactionInput;
+import org.bitcoinj.core.TransactionOutput;
+import org.bitcoinj.core.TransactionWitness;
+import org.bitcoinj.crypto.DeterministicKey;
+import org.bitcoinj.script.Script;
+import org.bitcoinj.script.ScriptBuilder;
+
+import org.bouncycastle.crypto.params.KeyParameter;
+
+import static com.google.common.base.Preconditions.checkNotNull;
+
+public class ClaimTransactionFactory {
+    private final NetworkParameters params;
+
+    public ClaimTransactionFactory(NetworkParameters params) {
+        this.params = params;
+    }
+
+    public Transaction createSignedClaimTransaction(Transaction warningTx,
+                                                    long nSequence,
+                                                    Address payoutAddress,
+                                                    long miningFee,
+                                                    DeterministicKey myMultiSigKeyPair,
+                                                    KeyParameter aesKey) throws TransactionVerificationException {
+        Transaction claimTx = createUnsignedClaimTransaction(warningTx, nSequence, payoutAddress, miningFee);
+        byte[] mySignature = signClaimTransaction(claimTx, warningTx, myMultiSigKeyPair, aesKey);
+        return finalizeClaimTransaction(warningTx, claimTx, mySignature);
+    }
+
+    private Transaction createUnsignedClaimTransaction(Transaction warningTx,
+                                                       long nSequence,
+                                                       Address payoutAddress,
+                                                       long miningFee)
+            throws AddressFormatException, TransactionVerificationException {
+
+        Transaction claimTx = new Transaction(params);
+
+        TransactionOutput warningTxOutput = warningTx.getOutput(0);
+        claimTx.addInput(warningTxOutput);
+        claimTx.getInput(0).setSequenceNumber(nSequence);
+
+        Coin amountWithoutMiningFee = warningTxOutput.getValue()
+                .subtract(Coin.valueOf(miningFee));
+        claimTx.addOutput(amountWithoutMiningFee, payoutAddress);
+
+        WalletService.printTx("Unsigned claimTx", claimTx);
+        WalletService.verifyTransaction(claimTx);
+        return claimTx;
+    }
+
+    private byte[] signClaimTransaction(Transaction claimTx,
+                                        Transaction warningTx,
+                                        DeterministicKey myMultiSigKeyPair,
+                                        KeyParameter aesKey)
+            throws AddressFormatException, TransactionVerificationException {
+
+        TransactionOutput warningTxPayoutOutput = warningTx.getOutput(0);
+        Script redeemScript = warningTxPayoutOutput.getScriptPubKey();
+        Coin redirectionTxInputValue = warningTxPayoutOutput.getValue();
+
+        Sha256Hash sigHash = claimTx.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("claimTx for sig creation", claimTx);
+        WalletService.verifyTransaction(claimTx);
+        return mySignature.encodeToDER();
+    }
+
+    private Transaction finalizeClaimTransaction(Transaction warningTx,
+                                                 Transaction claimTx,
+                                                 byte[] mySignature)
+            throws AddressFormatException, TransactionVerificationException {
+
+        TransactionInput input = claimTx.getInput(0);
+        input.setScriptSig(ScriptBuilder.createEmpty());
+
+        Script redeemScript = createRedeemScript(mySignature);
+        TransactionWitness witness = TransactionWitness.redeemP2WSH(redeemScript);
+        input.setWitness(witness);
+
+        WalletService.printTx("finalizeRedirectionTransaction", claimTx);
+        WalletService.verifyTransaction(claimTx);
+
+        Script scriptPubKey = warningTx.getOutput(0).getScriptPubKey();
+        input.getScriptSig().correctlySpends(claimTx, 0, witness, input.getValue(), scriptPubKey, Script.ALL_VERIFY_FLAGS);
+        return claimTx;
+    }
+
+    private Script createRedeemScript(byte[] mySignature) {
+        return new ScriptBuilder()
+                .data(mySignature)
+                .number(0)
+                .build();
+    }
+}

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

@@ -901,6 +901,20 @@ public Transaction finalizeRedirectionTx(Transaction warningTx,
         );
     }
 
+    ///////////////////////////////////////////////////////////////////////////////////////////
+    // Claim tx
+    ///////////////////////////////////////////////////////////////////////////////////////////
+
+    public Transaction createSignedClaimTx(Transaction warningTx,
+                                                    long nSequence,
+                                                    Address payoutAddress,
+                                                    long miningFee,
+                                                    DeterministicKey myMultiSigKeyPair,
+                                                    KeyParameter aesKey) throws TransactionVerificationException {
+        return new ClaimTransactionFactory(params)
+                .createSignedClaimTransaction(warningTx, nSequence, payoutAddress, miningFee, myMultiSigKeyPair, aesKey);
+    }
+
     ///////////////////////////////////////////////////////////////////////////////////////////
     // Standard payout tx
     ///////////////////////////////////////////////////////////////////////////////////////////