public TrustedBroadcastRequest FulfillOffer(
TransactionSignature clientSignature,
Script cashout,
FeeRate feeRate)
{
if (clientSignature == null)
{
throw new ArgumentNullException(nameof(clientSignature));
}
if (feeRate == null)
{
throw new ArgumentNullException(nameof(feeRate));
}
AssertState(SolverServerStates.WaitingFulfillment);
Script offerScript = GetOfferScript();
var offer = GetUnsignedOfferTransaction();
TransactionBuilder builder = new TransactionBuilder();
builder.Extensions.Add(new EscrowBuilderExtension());
builder.AddCoins(InternalState.EscrowedCoin);
builder.AddKeys(InternalState.EscrowKey);
var clientKey = InternalState.GetClientEscrowPubKey();
builder.AddKnownSignature(clientKey, clientSignature);
builder.SignTransactionInPlace(offer);
if (!builder.Verify(offer))
{
throw new PuzzleException("invalid-signature");
}
var offerCoin = offer.Outputs.AsCoins().First().ToScriptCoin(offerScript);
var solutions = InternalState.SolvedPuzzles.Select(s => s.SolutionKey).ToArray();
Transaction fulfill = new Transaction();
fulfill.Inputs.Add(new TxIn(offerCoin.Outpoint));
fulfill.Outputs.Add(new TxOut(offerCoin.Amount, cashout));
var size = new OfferBuilderExtension().EstimateScriptSigSize(offerCoin.Redeem);
fulfill.Outputs[0].Value -= feeRate.GetFee(size);
var signature = fulfill.Inputs.AsIndexedInputs().First().Sign(InternalState.FulfillKey, offerCoin, SigHash.All);
var fulfillScript = SolverScriptBuilder.CreateFulfillScript(signature, solutions);
fulfill.Inputs[0].ScriptSig = fulfillScript + Op.GetPushOp(offerCoin.Redeem.ToBytes());
InternalState.OfferClientSignature = clientSignature;
InternalState.Status = SolverServerStates.Completed;
return(new TrustedBroadcastRequest
{
Key = InternalState.FulfillKey,
PreviousScriptPubKey = offerCoin.ScriptPubKey,
Transaction = fulfill
});
}
private PubKey AssertValidSignature(TransactionSignature clientSignature, Transaction offer)
{
var signedHash = offer.Inputs.AsIndexedInputs().First().GetSignatureHash(InternalState.EscrowedCoin, clientSignature.SigHash);
var clientKey = InternalState.GetClientEscrowPubKey();
if (!clientKey.Verify(signedHash, clientSignature.Signature))
{
throw new PuzzleException("invalid-client-signature");
}
return(clientKey);
}
private PubKey AssertValidSignature(TransactionSignature clientSignature, Transaction offer)
{
var escrow = EscrowScriptPubKeyParameters.GetFromCoin(InternalState.EscrowedCoin);
var coin = InternalState.EscrowedCoin.Clone();
coin.OverrideScriptCode(escrow.GetInitiatorScriptCode());
var signedHash = offer.Inputs.AsIndexedInputs().First().GetSignatureHash(coin, clientSignature.SigHash);
var clientKey = InternalState.GetClientEscrowPubKey();
if (!clientKey.Verify(signedHash, clientSignature.Signature))
{
throw new PuzzleException("invalid-client-signature");
}
return(clientKey);
}
public TrustedBroadcastRequest GetSignedOfferTransaction()
{
AssertState(SolverServerStates.Completed);
var offerTransaction = GetUnsignedOfferTransaction();
TransactionBuilder txBuilder = new TransactionBuilder();
txBuilder.Extensions.Add(new EscrowBuilderExtension());
txBuilder.AddCoins(EscrowedCoin);
txBuilder.AddKnownSignature(InternalState.EscrowKey.PubKey, InternalState.OfferSignature);
txBuilder.AddKnownSignature(InternalState.GetClientEscrowPubKey(), InternalState.OfferClientSignature);
txBuilder.SignTransactionInPlace(offerTransaction);
return(new TrustedBroadcastRequest
{
Key = InternalState.EscrowKey,
Transaction = offerTransaction,
PreviousScriptPubKey = EscrowedCoin.ScriptPubKey
});
}