spend from p2sh with bitcoinj

Question

i am try to spend the coins on a p2sh

first, i generate p2sh and send coins to that p2sh

ECKey clientKey = new ECKey();
ECKey serverKey = new ECKey();
ECKey thirdPartyKey = new ECKey();
List<ECKey> keys = ImmutableList.of(clientKey, serverKey,thirdPartyKey);
Script multisigScript = ScriptBuilder.createP2SHOutputScript(2, keys);
String address = multisigScript.getToAddress(params).toString();

then i send coins to the "address" on testnet3

second, i use the wallet in bitcoinj to watch the "address" and get the tx

WalletAppKit walletAppKit = new WalletAppKit(params, new File("./btcWallet"), "test");
walletAppKit.startAsync();
walletAppKit.awaitRunning();
Wallet walletTemp = walletAppKit.wallet();
Address watchAddress = Address.fromString(params, "2NGY4n3Wc2iftWufhUg2MzZtccbkQWgdUiz");
walletTemp.addWatchedAddress(watchAddress,1576573079);
 Set<Transaction> transSet = walletTemp.getTransactions(false);

third, after i get the tx and the output, i want to spend it

TransactionOutput out = ...//output that the second step i get from the tx
Script scriptOut = out.getScriptPubKey()
Coin outValue = Coin.valueOf(10000);
Script redeemScript = ScriptBuilder.createRedeemScript(2, keys);
Address sendAddress = LegacyAddress.fromBase58(params, "2N6846hvswyZEdJ5DuEcjQZPaT5Xwb6PdGT");
Transaction spendTx = new Transaction(params);
spendTx.addOutput(outValue, sendAddress);
TransactionInput input = spendTx.addInput(out);

Sha256Hash sighash = spendTx.hashForSignature(0, redeemScript, Transaction.SigHash.ALL,
                        false);
ECKey.ECDSASignature cSignature = clientKey.sign(sighash);
ECKey.ECDSASignature sSignature = serverKey.sign(sighash);
TransactionSignature cTransactionSignature = new TransactionSignature(cSignature, Transaction.SigHash.ALL,
                        false);
TransactionSignature sTransactionSignature = new TransactionSignature(sSignature, Transaction.SigHash.ALL,
                        false);

Script inputScript = ScriptBuilder.createP2SHMultiSigInputScript(ImmutableList.of(cTransactionSignature, sTransactionSignature), scriptOut);
input.setScriptSig(inputScript);
input.verify(out);

it have error at "input.verify(out);",Script resulted in a non-true stack: [] [3044022043d0cdddb087c4db2937a3b656c37bf240fd95e16714125c0672875bb18b4c1902200f96e1ec0adc2258e324cbacba598cb72d502a4e3185212dea40c50b365d3fb901] []

i do not kown where my code is wrong and how to solve it.

find a similar problem, but not the same [1]: Errors when building/sending multisig transactions

Answer 1

Based on your example it looks like you are signing the same sighash twice, so it only looks like one key signed.

This example might help: https://github.com/magmahindenburg/MultisigExamples/blob/master/src/se/moar/bitcoin/multisig/MultisigPresentation.java

    // Sign the first part of the transaction using private key #1
    Sha256Hash sighash = spendTx.hashForSignature(0, redeemScript, Transaction.SigHash.ALL, false);
    ECKey.ECDSASignature ecdsaSignature = key1.sign(sighash);
    TransactionSignature transactionSignarture = new TransactionSignature(ecdsaSignature, Transaction.SigHash.ALL, false);

    // Create the sighash2 using the redeem script
    Sha256Hash sighash2 = spendTx.hashForSignature(0, redeemScript, Transaction.sighash2.ALL, false);
    ECKey.ECDSASignature secondSignature;

    // Take out the key and sign the signhash
    ECKey key2 = createKeyFromSha256Passphrase("Super secret key 2");
    secondSignature = key2.sign(sighash2);

    // Add the second signature to the signature list
    TransactionSignature transactionSignarture = new TransactionSignature(secondSignature, Transaction.sighash2.ALL, false);
    signatureList.add(transactionSignarture);

    // Rebuild p2sh multisig input script
    inputScript = ScriptBuilder.createP2SHMultiSigInputScript(signatureList, redeemScript);
    spendTx.getInput(0).setScriptSig(inputScript);

    System.out.println(byteArrayToHex(spendTx.bitcoinSerialize()));