Quote from: coins101 on September 29, 2016, 11:15:11 PM

No issues so far with using OP_Return as part of the proof process. BitSquare and a few others doing something similar already

Code:

// We add the hash ot OP_RETURN with a 0 amount output
TransactionOutput contractHashOutput = new TransactionOutput(params, preparedDepositTx, Coin.ZERO,
ScriptBuilder.createOpReturnScript(contractHash).getProgram());
preparedDepositTx.addOutput(contractHashOutput);

TransactionOutput takerTransactionOutput = null;
if (takerChangeOutputValue > 0 && takerChangeAddressString != null)
takerTransactionOutput = new TransactionOutput(params, preparedDepositTx, Coin.valueOf(takerChangeOutputValue),
new Address(params, takerChangeAddressString));

if (offererIsBuyer) {
// Add optional buyer outputs
if (offererOutput != null)
preparedDepositTx.addOutput(offererOutput);

// Add optional seller outputs
if (takerTransactionOutput != null)
preparedDepositTx.addOutput(takerTransactionOutput);
} else {
// taker is buyer role

// Add optional seller outputs
if (takerTransactionOutput != null)
preparedDepositTx.addOutput(takerTransactionOutput);

// Add optional buyer outputs
if (offererOutput != null)
preparedDepositTx.addOutput(offererOutput);
}

// Sign inputs
int start = offererIsBuyer ? 0 : takerRawTransactionInputs.size();
int end = offererIsBuyer ? offererInputs.size() : preparedDepositTx.getInputs().size();
for (int i = start; i < end; i++) {
TransactionInput input = preparedDepositTx.getInput(i);
signInput(preparedDepositTx, input, i);
checkScriptSig(preparedDepositTx, input, i);
}

verifyTransaction(preparedDepositTx);

printTxWithInputs("preparedDepositTx", preparedDepositTx);

return new PreparedDepositTxAndOffererInputs(offererRawTransactionInputs, preparedDepositTx.bitcoinSerialize());
}

Code:

// Check if OP_RETURN output with contract hash matches the one from the offerer
   TransactionOutput contractHashOutput = new TransactionOutput(params, offerersDepositTx, Coin.ZERO,
   ScriptBuilder.createOpReturnScript(contractHash).getProgram());
   log.debug("contractHashOutput " + contractHashOutput);
   TransactionOutput offerersContractHashOutput = offerersDepositTx.getOutputs().get(1);
   log.debug("offerersContractHashOutput " + offerersContractHashOutput);
   if (!offerersContractHashOutput.getScriptPubKey().equals(contractHashOutput.getScriptPubKey()))
   throw new TransactionVerificationException("Offerers transaction output for the contract hash is not matching takers version.");

How does this work with the initial election of Servicenodes and the final payment made to that node?

With the model outlined you would have to wait for a certain number of Bitcoin confirmations before a node was paid, so you would end up with a backlog of payments?