public IActionResult CoinJoin([FromBody] CoinJoinRequest request)
{
var roundId = Global.StateMachine.RoundId;
TumblerPhase phase = TumblerPhase.Signing;
try
{
if (Global.StateMachine.Phase != TumblerPhase.Signing || !Global.StateMachine.AcceptRequest)
{
return(new ObjectResult(new FailureResponse {
Message = "Wrong phase"
}));
}
if (string.IsNullOrWhiteSpace(request.UniqueId))
{
return(new BadRequestResult());
}
Global.StateMachine.FindAlice(request.UniqueId, throwException: true);
AssertPhase(roundId, phase);
return(new ObjectResult(new CoinJoinResponse
{
Transaction = Global.StateMachine.UnsignedCoinJoinHex
}));
}
catch (Exception ex)
{
return(new ObjectResult(new FailureResponse {
Message = ex.Message
}));
}
}
private static void AssertPhase(int roundId, TumblerPhase phase)
{
if (Global.StateMachine.Phase != phase || Global.StateMachine.RoundId != roundId)
{
throw new InvalidOperationException("Phase timed out");
}
}
public TumblerStateMachine()
{
Phase = TumblerPhase.InputRegistration;
RoundId = 0;
AcceptRequest = false;
FallBackRound = false;
CoinJoin = null;
InputRegistrationStopwatch = new Stopwatch();
}
public void UpdatePhase(TumblerPhase phase)
{
if (phase == Phase)
{
return;
}
AcceptRequest = false;
Phase = phase;
_ctsPhaseCancel.Cancel();
_ctsPhaseCancel = new CancellationTokenSource();
}
public IActionResult ConnectionConfirmation([FromBody] ConnectionConfirmationRequest request)
{
var roundId = Global.StateMachine.RoundId;
TumblerPhase phase = TumblerPhase.ConnectionConfirmation;
try
{
if (Global.StateMachine.Phase != TumblerPhase.ConnectionConfirmation || !Global.StateMachine.AcceptRequest)
{
return(new ObjectResult(new FailureResponse {
Message = "Wrong phase"
}));
}
if (string.IsNullOrWhiteSpace(request.UniqueId))
{
return(new BadRequestResult());
}
Alice alice = Global.StateMachine.FindAlice(request.UniqueId, throwException: true);
if (alice.State == AliceState.ConnectionConfirmed)
{
return(new ObjectResult(new ConnectionConfirmationResponse {
RoundHash = Global.StateMachine.RoundHash
}));
}
AssertPhase(roundId, phase);
alice.State = AliceState.ConnectionConfirmed;
try
{
return(new ObjectResult(new ConnectionConfirmationResponse {
RoundHash = Global.StateMachine.RoundHash
}));
}
finally
{
if (Global.StateMachine.Alices.All(x => x.State == AliceState.ConnectionConfirmed))
{
Global.StateMachine.UpdatePhase(TumblerPhase.OutputRegistration);
}
}
}
catch (Exception ex)
{
return(new ObjectResult(new FailureResponse {
Message = ex.Message
}));
}
}
public async Task <IActionResult> InputsAsync([FromBody] InputsRequest request)
{
var roundId = Global.StateMachine.RoundId;
TumblerPhase phase = TumblerPhase.InputRegistration;
try
{
if (Global.StateMachine.Phase != TumblerPhase.InputRegistration || !Global.StateMachine.AcceptRequest)
{
return(new ObjectResult(new FailureResponse {
Message = "Wrong phase"
}));
}
// Check not nulls
string blindedOutputString = request.BlindedOutput.Trim();
if (string.IsNullOrWhiteSpace(blindedOutputString))
{
return(new BadRequestResult());
}
if (string.IsNullOrWhiteSpace(request.ChangeOutput))
{
return(new BadRequestResult());
}
if (request.Inputs == null || request.Inputs.Count() == 0)
{
return(new BadRequestResult());
}
// Check format (parse everyting))
if (Global.StateMachine.BlindedOutputs.Contains(blindedOutputString))
{
throw new ArgumentException("Blinded output has already been registered");
}
byte[] blindedOutput = HexHelpers.GetBytes(blindedOutputString);
Network network = Global.Config.Network;
var changeOutput = new BitcoinWitPubKeyAddress(request.ChangeOutput, expectedNetwork: network);
if (request.Inputs.Count() > Global.Config.MaximumInputsPerAlices)
{
throw new NotSupportedException("Too many inputs provided");
}
var inputs = new HashSet <(TxOut Output, OutPoint OutPoint)>();
var alicesToRemove = new HashSet <Guid>();
using (await InputRegistrationLock.LockAsync())
{
foreach (InputProofModel input in request.Inputs)
{
var op = new OutPoint();
op.FromHex(input.Input);
if (inputs.Any(x => x.OutPoint.Hash == op.Hash && x.OutPoint.N == op.N))
{
throw new ArgumentException("Attempting to register an input twice is not permitted");
}
foreach (var a in Global.StateMachine.Alices)
{
if (a.Inputs.Any(x => x.OutPoint.Hash == op.Hash && x.OutPoint.N == op.N))
{
alicesToRemove.Add(a.UniqueId); // input is already registered by this alice, remove it if all the checks are completed fine
}
}
BannedUtxo banned = Global.UtxoReferee.Utxos.FirstOrDefault(x => x.Utxo.Hash == op.Hash && x.Utxo.N == op.N);
if (banned != default(BannedUtxo))
{
var maxBan = (int)TimeSpan.FromDays(30).TotalMinutes;
int banLeft = maxBan - (int)((DateTimeOffset.UtcNow - banned.TimeOfBan).TotalMinutes);
throw new ArgumentException($"Input is banned for {banLeft} minutes");
}
var getTxOutResponse = await Global.RpcClient.GetTxOutAsync(op.Hash, (int)op.N, true);
// Check if inputs are unspent
if (getTxOutResponse == null)
{
throw new ArgumentException("Provided input is not unspent");
}
// Check if inputs are unconfirmed, if so check if they are part of previous CoinJoin
if (getTxOutResponse.Confirmations <= 0)
{
if (!Global.CoinJoinStore.Transactions
.Any(x => x.State >= CoinJoinTransactionState.Succeeded && x.Transaction.GetHash() == op.Hash))
{
throw new ArgumentException("Provided input is not confirmed, nor spends a previous CJ transaction");
}
else
{
// after 24 unconfirmed cj in the mempool dont't let unconfirmed coinjoin to be registered
var unconfirmedCoinJoins = Global.CoinJoinStore.Transactions.Where(x => x.State == CoinJoinTransactionState.Succeeded);
if (unconfirmedCoinJoins.Count() >= 24)
{
var toFailed = new HashSet <uint256>();
var toConfirmed = new HashSet <uint256>();
foreach (var tx in unconfirmedCoinJoins)
{
RPCResponse getRawTransactionResponse = (await Global.RpcClient.SendCommandAsync("getrawtransaction", tx.Transaction.GetHash().ToString(), true));
if (string.IsNullOrWhiteSpace(getRawTransactionResponse?.ResultString))
{
toFailed.Add(tx.Transaction.GetHash());
}
if (getRawTransactionResponse.Result.Value <int>("confirmations") > 0)
{
toConfirmed.Add(tx.Transaction.GetHash());
}
}
foreach (var tx in toFailed)
{
Global.CoinJoinStore.TryUpdateState(tx, CoinJoinTransactionState.Failed);
}
foreach (var tx in toConfirmed)
{
Global.CoinJoinStore.TryUpdateState(tx, CoinJoinTransactionState.Confirmed);
}
if (toFailed.Count + toConfirmed.Count > 0)
{
await Global.CoinJoinStore.ToFileAsync(Global.CoinJoinStorePath);
}
// if couldn't remove any unconfirmed tx then refuse registration
if (Global.CoinJoinStore.Transactions.Count(x => x.State == CoinJoinTransactionState.Succeeded) >= 24)
{
throw new ArgumentException("Registering unconfirmed CJ transaction output is currently not allowed due to too long mempool chain");
}
}
}
}
// Check coinbase > 100
if (getTxOutResponse.Confirmations < 100)
{
if (getTxOutResponse.IsCoinBase)
{
throw new ArgumentException("Provided input is unspendable");
}
}
// Check if inputs are native segwit
if (getTxOutResponse.ScriptPubKeyType != "witness_v0_keyhash")
{
throw new ArgumentException("Provided input is not witness_v0_keyhash");
}
var txout = getTxOutResponse.TxOut;
var address = (BitcoinWitPubKeyAddress)txout.ScriptPubKey.GetDestinationAddress(network);
// Check if proofs are valid
var validProof = address.VerifyMessage(blindedOutputString, input.Proof);
if (!validProof)
{
throw new ArgumentException("Provided proof is invalid");
}
inputs.Add((txout, op));
}
// Check if inputs have enough coins
Money amount = Money.Zero;
foreach (Money val in inputs.Select(x => x.Output.Value))
{
amount += val;
}
Money feeToPay = (inputs.Count() * Global.StateMachine.FeePerInputs + 2 * Global.StateMachine.FeePerOutputs);
Money changeAmount = amount - (Global.StateMachine.Denomination + feeToPay);
if (changeAmount < Money.Zero + new Money(548)) // 546 is dust
{
throw new ArgumentException("Total provided inputs must be > denomination + fee + dust");
}
byte[] signature = Global.RsaKey.SignBlindedData(blindedOutput);
Global.StateMachine.BlindedOutputs.Add(blindedOutputString);
Guid uniqueId = Guid.NewGuid();
var alice = new Alice
{
UniqueId = uniqueId,
ChangeOutput = changeOutput,
ChangeAmount = changeAmount,
State = AliceState.InputsRegistered
};
alice.Inputs = new ConcurrentHashSet <(TxOut Output, OutPoint OutPoint)>();
foreach (var input in inputs)
{
alice.Inputs.Add(input);
}
AssertPhase(roundId, phase);
foreach (var aliceToRemove in alicesToRemove)
{
if (Global.StateMachine.TryRemoveAlice(aliceToRemove))
{
await Global.StateMachine.BroadcastPeerRegisteredAsync();
}
}
Global.StateMachine.Alices.Add(alice);
await Global.StateMachine.BroadcastPeerRegisteredAsync();
if (Global.StateMachine.Alices.Count >= Global.StateMachine.AnonymitySet)
{
Global.StateMachine.UpdatePhase(TumblerPhase.ConnectionConfirmation);
}
TumblerStateMachine.EstimateInputAndOutputSizes(out int inputSizeInBytes, out int outputSizeInBytes);
int estimatedTxSize = Global.StateMachine.Alices.SelectMany(x => x.Inputs).Count() * inputSizeInBytes + 2 * outputSizeInBytes;
if (estimatedTxSize >= 90000) // standard transaction is < 100KB
{
Global.StateMachine.UpdatePhase(TumblerPhase.ConnectionConfirmation);
}
var ret = new ObjectResult(new InputsResponse()
{
UniqueId = uniqueId.ToString(),
SignedBlindedOutput = HexHelpers.ToString(signature)
});
return(ret);
}
}
catch (Exception ex)
{
return(new ObjectResult(new FailureResponse {
Message = ex.Message
}));
}
}
public IActionResult Output([FromBody] OutputRequest request)
{
var roundId = Global.StateMachine.RoundId;
TumblerPhase phase = TumblerPhase.OutputRegistration;
try
{
if (Global.StateMachine.Phase != TumblerPhase.OutputRegistration || !Global.StateMachine.AcceptRequest)
{
return(new ObjectResult(new FailureResponse {
Message = "Wrong phase"
}));
}
if (string.IsNullOrWhiteSpace(request.Output))
{
return(new BadRequestResult());
}
if (string.IsNullOrWhiteSpace(request.Signature))
{
return(new BadRequestResult());
}
if (string.IsNullOrWhiteSpace(request.RoundHash))
{
return(new BadRequestResult());
}
if (request.RoundHash != Global.StateMachine.RoundHash)
{
throw new ArgumentException("Wrong round hash provided");
}
var output = new BitcoinWitPubKeyAddress(request.Output, expectedNetwork: Global.Config.Network);
// if not already registered
if (Global.StateMachine.Bobs.Any(x => x.Output == output))
{
return(new ObjectResult(new SuccessResponse()));
}
if (Global.RsaKey.PubKey.Verify(HexHelpers.GetBytes(request.Signature), Encoding.UTF8.GetBytes(request.Output)))
{
try
{
AssertPhase(roundId, phase);
Global.StateMachine.Bobs.Add(new Bob {
Output = output
});
return(new ObjectResult(new SuccessResponse()));
}
finally
{
if (Global.StateMachine.Alices.Count == Global.StateMachine.Bobs.Count)
{
Global.StateMachine.UpdatePhase(TumblerPhase.Signing);
}
}
}
else
{
throw new ArgumentException("Bad output");
}
}
catch (Exception ex)
{
return(new ObjectResult(new FailureResponse {
Message = ex.Message
}));
}
}
