public static bool TryVerifyPartyPaymentTx(
IBitcoinBasedTransaction tx,
Swap swap,
ICurrencies currencies,
byte[] secretHash,
long refundLockTime,
out Error error)
{
if (tx == null)
{
throw new ArgumentNullException(nameof(tx));
}
if (swap == null)
{
throw new ArgumentNullException(nameof(swap));
}
var currency = currencies.Get <BitcoinBasedCurrency>(swap.PurchasedCurrency);
var partyRedeemScript = new Script(Convert.FromBase64String(swap.PartyRedeemScript));
var targetAddressHash = new BitcoinPubKeyAddress(swap.ToAddress, currency.Network)
.Hash
.ToBytes();
var hasSwapOutput = false;
foreach (var txOutput in tx.Outputs)
{
try
{
var output = (BitcoinBasedTxOutput)txOutput;
if (!output.IsPayToScriptHash(partyRedeemScript))
{
continue;
}
// check address
var outputTargetAddressHash = BitcoinBasedSwapTemplate.ExtractTargetPkhFromHtlcP2PkhSwapPayment(
script: partyRedeemScript);
if (!outputTargetAddressHash.SequenceEqual(targetAddressHash))
{
continue;
}
var outputSecretHash = BitcoinBasedSwapTemplate.ExtractSecretHashFromHtlcP2PkhSwapPayment(
script: partyRedeemScript);
if (!outputSecretHash.SequenceEqual(secretHash))
{
continue;
}
hasSwapOutput = true;
// check swap output refund lock time
var outputLockTime = BitcoinBasedSwapTemplate.ExtractLockTimeFromHtlcP2PkhSwapPayment(
script: partyRedeemScript);
var swapTimeUnix = (long)swap.TimeStamp.ToUniversalTime().ToUnixTime();
if (outputLockTime - swapTimeUnix < refundLockTime)
{
error = new Error(
code: Errors.InvalidRefundLockTime,
description: "Invalid refund time",
swap: swap);
return(false);
}
// check swap amount
var side = swap.Symbol
.OrderSideForBuyCurrency(currency.Name)
.Opposite();
var requiredAmount = AmountHelper.QtyToAmount(side, swap.Qty, swap.Price, currency.DigitsMultiplier);
var requiredAmountInSatoshi = currency.CoinToSatoshi(requiredAmount);
if (output.Value < requiredAmountInSatoshi)
{
error = new Error(
code: Errors.InvalidSwapPaymentTxAmount,
description: "Invalid payment tx amount",
swap: swap);
return(false);
}
}
catch (Exception e)
{
Log.Error(e, "Transaction verification error");
error = new Error(
code: Errors.TransactionVerificationError,
description: e.Message,
swap: swap);
return(false);
}
}
if (!hasSwapOutput)
{
error = new Error(
code: Errors.TransactionVerificationError,
description: $"No swap outputs in tx @{tx.Id} for address {swap.ToAddress}",
swap: swap);
return(false);
}
// todo: check fee
// todo: try to verify
error = null;
return(true);
}
