/**
  * Creates the initial multisig contract and incomplete refund transaction which can be requested
  * at the appropriate time using {@link PaymentChannelClientState#getIncompleteRefundTransaction}
  * and {@link PaymentChannelClientState#getMultisigContract()}. The way the contract is crafted
  * can be adjusted by overriding {@link
  * PaymentChannelClientState#editContractSendRequest(com.google.bitcoin.core.Wallet.SendRequest)}.
  * By default unconfirmed coins are allowed to be used, as for micropayments the risk should be
  * relatively low.
  *
  * @throws ValueOutOfRangeException if the value being used is too small to be accepted by the
  *     network
  * @throws InsufficientMoneyException if the wallet doesn't contain enough balance to initiate
  */
 public synchronized void initiate() throws ValueOutOfRangeException, InsufficientMoneyException {
   final NetworkParameters params = wallet.getParams();
   Transaction template = new Transaction(params);
   // We always place the client key before the server key because, if either side wants some
   // privacy, they can
   // use a fresh key for the the multisig contract and nowhere else
   List<ECKey> keys = Lists.newArrayList(myKey, serverMultisigKey);
   // There is also probably a change output, but we don't bother shuffling them as it's obvious
   // from the
   // format which one is the change. If we start obfuscating the change output better in future
   // this may
   // be worth revisiting.
   TransactionOutput multisigOutput =
       template.addOutput(totalValue, ScriptBuilder.createMultiSigOutputScript(2, keys));
   if (multisigOutput.getMinNonDustValue().compareTo(totalValue) > 0)
     throw new ValueOutOfRangeException("totalValue too small to use");
   Wallet.SendRequest req = Wallet.SendRequest.forTx(template);
   req.coinSelector = AllowUnconfirmedCoinSelector.get();
   editContractSendRequest(req);
   req.shuffleOutputs = false; // TODO: Fix things so shuffling is usable.
   wallet.completeTx(req);
   Coin multisigFee = req.tx.getFee();
   multisigContract = req.tx;
   // Build a refund transaction that protects us in the case of a bad server that's just trying to
   // cause havoc
   // by locking up peoples money (perhaps as a precursor to a ransom attempt). We time lock it so
   // the server
   // has an assurance that we cannot take back our money by claiming a refund before the channel
   // closes - this
   // relies on the fact that since Bitcoin 0.8 time locked transactions are non-final. This will
   // need to change
   // in future as it breaks the intended design of timelocking/tx replacement, but for now it
   // simplifies this
   // specific protocol somewhat.
   refundTx = new Transaction(params);
   refundTx
       .addInput(multisigOutput)
       .setSequenceNumber(0); // Allow replacement when it's eventually reactivated.
   refundTx.setLockTime(expiryTime);
   if (totalValue.compareTo(Coin.CENT) < 0) {
     // Must pay min fee.
     final Coin valueAfterFee = totalValue.subtract(Transaction.REFERENCE_DEFAULT_MIN_TX_FEE);
     if (Transaction.MIN_NONDUST_OUTPUT.compareTo(valueAfterFee) > 0)
       throw new ValueOutOfRangeException("totalValue too small to use");
     refundTx.addOutput(valueAfterFee, myKey.toAddress(params));
     refundFees = multisigFee.add(Transaction.REFERENCE_DEFAULT_MIN_TX_FEE);
   } else {
     refundTx.addOutput(totalValue, myKey.toAddress(params));
     refundFees = multisigFee;
   }
   refundTx.getConfidence().setSource(TransactionConfidence.Source.SELF);
   log.info(
       "initiated channel with multi-sig contract {}, refund {}",
       multisigContract.getHashAsString(),
       refundTx.getHashAsString());
   state = State.INITIATED;
   // Client should now call getIncompleteRefundTransaction() and send it to the server.
 }
Ejemplo n.º 2
0
  private void readTransaction(Protos.Transaction txProto, NetworkParameters params) {
    Transaction tx = new Transaction(params);
    if (txProto.hasUpdatedAt()) {
      tx.setUpdateTime(new Date(txProto.getUpdatedAt()));
    }

    for (Protos.TransactionOutput outputProto : txProto.getTransactionOutputList()) {
      BigInteger value = BigInteger.valueOf(outputProto.getValue());
      byte[] scriptBytes = outputProto.getScriptBytes().toByteArray();
      TransactionOutput output = new TransactionOutput(params, tx, value, scriptBytes);
      tx.addOutput(output);
    }

    for (Protos.TransactionInput transactionInput : txProto.getTransactionInputList()) {
      byte[] scriptBytes = transactionInput.getScriptBytes().toByteArray();
      TransactionOutPoint outpoint =
          new TransactionOutPoint(
              params,
              transactionInput.getTransactionOutPointIndex(),
              byteStringToHash(transactionInput.getTransactionOutPointHash()));
      TransactionInput input = new TransactionInput(params, tx, scriptBytes, outpoint);
      if (transactionInput.hasSequence()) {
        input.setSequenceNumber(transactionInput.getSequence());
      }
      tx.addInput(input);
    }

    for (ByteString blockHash : txProto.getBlockHashList()) {
      tx.addBlockAppearance(byteStringToHash(blockHash));
    }

    if (txProto.hasLockTime()) {
      tx.setLockTime(0xffffffffL & txProto.getLockTime());
    }

    // Transaction should now be complete.
    Sha256Hash protoHash = byteStringToHash(txProto.getHash());
    Preconditions.checkState(
        tx.getHash().equals(protoHash),
        "Transaction did not deserialize completely: %s vs %s",
        tx.getHash(),
        protoHash);
    Preconditions.checkState(
        !txMap.containsKey(txProto.getHash()),
        "Wallet contained duplicate transaction %s",
        byteStringToHash(txProto.getHash()));
    txMap.put(txProto.getHash(), tx);
  }