public async Task <IActionResult> PostInputsAsync([FromBody] InputsRequest request)
{
// Validate request.
if (!ModelState.IsValid ||
request == null ||
string.IsNullOrWhiteSpace(request.BlindedOutputScriptHex) ||
string.IsNullOrWhiteSpace(request.ChangeOutputScript) ||
request.Inputs == null ||
request.Inputs.Count() == 0 ||
request.Inputs.Any(x => x.Input == null ||
x.Input.Hash == null ||
string.IsNullOrWhiteSpace(x.Proof)))
{
return(BadRequest("Invalid request."));
}
if (request.Inputs.Count() > 7)
{
return(BadRequest("Maximum 7 inputs can be registered."));
}
using (await InputsLock.LockAsync())
{
CcjRound round = Coordinator.GetCurrentInputRegisterableRound();
// Do more checks.
try
{
if (round.ContainsBlindedOutputScriptHex(request.BlindedOutputScriptHex, out _))
{
return(BadRequest("Blinded output has already been registered."));
}
var changeOutput = new Script(request.ChangeOutputScript);
var inputs = new HashSet <(OutPoint OutPoint, TxOut Output)>();
var alicesToRemove = new HashSet <Guid>();
foreach (InputProofModel inputProof in request.Inputs)
{
if (inputs.Any(x => x.OutPoint == inputProof.Input))
{
return(BadRequest("Cannot register an input twice."));
}
if (round.ContainsInput(inputProof.Input, out List <Alice> tr))
{
alicesToRemove.UnionWith(tr.Select(x => x.UniqueId)); // Input is already registered by this alice, remove it later if all the checks are completed fine.
}
if (Coordinator.AnyRunningRoundContainsInput(inputProof.Input, out List <Alice> tnr))
{
if (tr.Union(tnr).Count() > tr.Count())
{
return(BadRequest("Input is already registered in another round."));
}
}
var bannedElem = Coordinator.UtxoReferee.BannedUtxos.SingleOrDefault(x => x.Key == inputProof.Input);
if (bannedElem.Key != default)
{
int maxBan = (int)TimeSpan.FromDays(30).TotalMinutes;
int banLeft = maxBan - (int)((DateTimeOffset.UtcNow - bannedElem.Value.timeOfBan).TotalMinutes);
if (banLeft > 0)
{
return(BadRequest($"Input is banned from participation for {banLeft} minutes: {inputProof.Input.N}:{inputProof.Input.Hash}."));
}
else
{
await Coordinator.UtxoReferee.UnbanAsync(bannedElem.Key);
}
}
GetTxOutResponse getTxOutResponse = await RpcClient.GetTxOutAsync(inputProof.Input.Hash, (int)inputProof.Input.N, includeMempool : true);
// Check if inputs are unspent.
if (getTxOutResponse == null)
{
return(BadRequest("Provided input is not unspent."));
}
// Check if unconfirmed.
if (getTxOutResponse.Confirmations <= 0)
{
// If it spends a CJ then it may be acceptable to register.
if (!Coordinator.ContainsCoinJoin(inputProof.Input.Hash))
{
return(BadRequest("Provided input is neither confirmed, nor is from an unconfirmed coinjoin."));
}
// After 24 unconfirmed cj in the mempool dont't let unconfirmed coinjoin to be registered.
if (await Coordinator.IsUnconfirmedCoinJoinLimitReachedAsync())
{
return(BadRequest("Provided input is from an unconfirmed coinjoin, but the maximum number of unconfirmed coinjoins is reached."));
}
}
// Check if immature.
if (getTxOutResponse.Confirmations <= 100)
{
if (getTxOutResponse.IsCoinBase)
{
return(BadRequest("Provided input is immature."));
}
}
// Check if inputs are native segwit.
if (getTxOutResponse.ScriptPubKeyType != "witness_v0_keyhash")
{
return(BadRequest("Provided input must be witness_v0_keyhash."));
}
TxOut txout = getTxOutResponse.TxOut;
var address = (BitcoinWitPubKeyAddress)txout.ScriptPubKey.GetDestinationAddress(Network);
// Check if proofs are valid.
bool validProof;
try
{
validProof = address.VerifyMessage(request.BlindedOutputScriptHex, inputProof.Proof);
}
catch (FormatException ex)
{
return(BadRequest($"Provided proof is invalid: {ex.Message}"));
}
if (!validProof)
{
return(BadRequest("Provided proof is invalid."));
}
inputs.Add((inputProof.Input, txout));
}
// Check if inputs have enough coins.
Money inputSum = inputs.Sum(x => x.Output.Value);
Money networkFeeToPay = (inputs.Count() * round.FeePerInputs + 2 * round.FeePerOutputs);
Money changeAmount = inputSum - (round.Denomination + networkFeeToPay);
if (changeAmount < Money.Zero)
{
return(BadRequest($"Not enough inputs are provided. Fee to pay: {networkFeeToPay.ToString(false, true)} BTC. Round denomination: {round.Denomination.ToString(false, true)} BTC. Only provided: {inputSum.ToString(false, true)} BTC."));
}
// Make sure Alice checks work.
var alice = new Alice(inputs, networkFeeToPay, new Script(request.ChangeOutputScript), request.BlindedOutputScriptHex);
foreach (Guid aliceToRemove in alicesToRemove)
{
round.RemoveAlicesBy(aliceToRemove);
}
round.AddAlice(alice);
// All checks are good. Sign.
byte[] blindedData;
try
{
blindedData = ByteHelpers.FromHex(request.BlindedOutputScriptHex);
}
catch
{
return(BadRequest("Invalid blinded output hex."));
}
Logger.LogDebug <ChaumianCoinJoinController>($"Blinded data hex: {request.BlindedOutputScriptHex}");
Logger.LogDebug <ChaumianCoinJoinController>($"Blinded data array size: {blindedData.Length}");
byte[] signature = RsaKey.SignBlindedData(blindedData);
// Check if phase changed since.
if (round.Status != ChaumianCoinJoin.CcjRoundStatus.Running || round.Phase != CcjRoundPhase.InputRegistration)
{
return(base.StatusCode(StatusCodes.Status503ServiceUnavailable, "The state of the round changed while handling the request. Try again."));
}
// Progress round if needed.
if (round.CountAlices() >= round.AnonymitySet)
{
await round.RemoveAlicesIfInputsSpentAsync();
if (round.CountAlices() >= round.AnonymitySet)
{
await round.ExecuteNextPhaseAsync(CcjRoundPhase.ConnectionConfirmation);
}
}
var resp = new InputsResponse
{
UniqueId = alice.UniqueId,
BlindedOutputSignature = signature,
RoundId = round.RoundId
};
return(Ok(resp));
}
catch (Exception ex)
{
Logger.LogDebug <ChaumianCoinJoinController>(ex);
return(BadRequest(ex.Message));
}
}
}
public async Task <IActionResult> PostInputsAsync([FromBody] InputsRequest request)
{
// Validate request.
if (!ModelState.IsValid ||
request is null ||
string.IsNullOrWhiteSpace(request.BlindedOutputScriptHex) ||
string.IsNullOrWhiteSpace(request.ChangeOutputAddress) ||
request.Inputs is null ||
!request.Inputs.Any() ||
request.Inputs.Any(x => x.Input == default(TxoRef) ||
x.Input.TransactionId is null ||
string.IsNullOrWhiteSpace(x.Proof)))
{
return(BadRequest("Invalid request."));
}
if (request.Inputs.Count() > 7)
{
return(BadRequest("Maximum 7 inputs can be registered."));
}
using (await InputsLock.LockAsync())
{
CcjRound round = Coordinator.GetCurrentInputRegisterableRound();
// Do more checks.
try
{
if (round.ContainsBlindedOutputScriptHex(request.BlindedOutputScriptHex, out _))
{
return(BadRequest("Blinded output has already been registered."));
}
BitcoinAddress changeOutputAddress;
try
{
changeOutputAddress = BitcoinAddress.Create(request.ChangeOutputAddress, Network);
}
catch (FormatException ex)
{
return(BadRequest($"Invalid ChangeOutputAddress. Details: {ex.Message}"));
}
var inputs = new HashSet <Coin>();
var alicesToRemove = new HashSet <Guid>();
foreach (InputProofModel inputProof in request.Inputs)
{
if (inputs.Any(x => x.Outpoint == inputProof.Input))
{
return(BadRequest("Cannot register an input twice."));
}
if (round.ContainsInput(inputProof.Input.ToOutPoint(), out List <Alice> tr))
{
alicesToRemove.UnionWith(tr.Select(x => x.UniqueId)); // Input is already registered by this alice, remove it later if all the checks are completed fine.
}
if (Coordinator.AnyRunningRoundContainsInput(inputProof.Input.ToOutPoint(), out List <Alice> tnr))
{
if (tr.Union(tnr).Count() > tr.Count())
{
return(BadRequest("Input is already registered in another round."));
}
}
OutPoint outpoint = inputProof.Input.ToOutPoint();
var bannedElem = await Coordinator.UtxoReferee.TryGetBannedAsync(outpoint, notedToo : false);
if (bannedElem != null)
{
return(BadRequest($"Input is banned from participation for {(int)bannedElem.Value.bannedRemaining.TotalMinutes} minutes: {inputProof.Input.Index}:{inputProof.Input.TransactionId}."));
}
GetTxOutResponse getTxOutResponse = await RpcClient.GetTxOutAsync(inputProof.Input.TransactionId, (int)inputProof.Input.Index, includeMempool : true);
// Check if inputs are unspent.
if (getTxOutResponse is null)
{
return(BadRequest($"Provided input is not unspent: {inputProof.Input.Index}:{inputProof.Input.TransactionId}."));
}
// Check if unconfirmed.
if (getTxOutResponse.Confirmations <= 0)
{
// If it spends a CJ then it may be acceptable to register.
if (!Coordinator.ContainsCoinJoin(inputProof.Input.TransactionId))
{
return(BadRequest("Provided input is neither confirmed, nor is from an unconfirmed coinjoin."));
}
// Check if mempool would accept a fake transaction created with the registered inputs.
// This will catch ascendant/descendant count and size limits for example.
var result = await RpcClient.TestMempoolAcceptAsync(new Coin(inputProof.Input.ToOutPoint(), getTxOutResponse.TxOut));
if (!result.accept)
{
return(BadRequest($"Provided input is from an unconfirmed coinjoin, but a limit is reached: {result.rejectReason}"));
}
}
// Check if immature.
if (getTxOutResponse.Confirmations <= 100)
{
if (getTxOutResponse.IsCoinBase)
{
return(BadRequest("Provided input is immature."));
}
}
// Check if inputs are native segwit.
if (getTxOutResponse.ScriptPubKeyType != "witness_v0_keyhash")
{
return(BadRequest("Provided input must be witness_v0_keyhash."));
}
TxOut txout = getTxOutResponse.TxOut;
var address = (BitcoinWitPubKeyAddress)txout.ScriptPubKey.GetDestinationAddress(Network);
// Check if proofs are valid.
bool validProof;
try
{
validProof = address.VerifyMessage(request.BlindedOutputScriptHex, inputProof.Proof);
}
catch (FormatException ex)
{
return(BadRequest($"Provided proof is invalid: {ex.Message}"));
}
if (!validProof)
{
await Coordinator.UtxoReferee.BanUtxosAsync(1, DateTimeOffset.UtcNow, forceNoted : false, round.RoundId, outpoint);
return(BadRequest("Provided proof is invalid."));
}
inputs.Add(new Coin(inputProof.Input.ToOutPoint(), txout));
}
// Check if inputs have enough coins.
Money inputSum = inputs.Sum(x => x.Amount);
Money networkFeeToPay = (inputs.Count() * round.FeePerInputs) + (2 * round.FeePerOutputs);
Money changeAmount = inputSum - (round.Denomination + networkFeeToPay);
if (changeAmount < Money.Zero)
{
return(BadRequest($"Not enough inputs are provided. Fee to pay: {networkFeeToPay.ToString(false, true)} BTC. Round denomination: {round.Denomination.ToString(false, true)} BTC. Only provided: {inputSum.ToString(false, true)} BTC."));
}
// Make sure Alice checks work.
var alice = new Alice(inputs, networkFeeToPay, changeOutputAddress, request.BlindedOutputScriptHex);
foreach (Guid aliceToRemove in alicesToRemove)
{
round.RemoveAlicesBy(aliceToRemove);
}
round.AddAlice(alice);
// All checks are good. Sign.
byte[] blindedData;
try
{
blindedData = ByteHelpers.FromHex(request.BlindedOutputScriptHex);
}
catch
{
return(BadRequest("Invalid blinded output hex."));
}
byte[] signature = RsaKey.SignBlindedData(blindedData);
// Check if phase changed since.
if (round.Status != CcjRoundStatus.Running || round.Phase != CcjRoundPhase.InputRegistration)
{
return(base.StatusCode(StatusCodes.Status503ServiceUnavailable, "The state of the round changed while handling the request. Try again."));
}
// Progress round if needed.
if (round.CountAlices() >= round.AnonymitySet)
{
await round.RemoveAlicesIfAnInputRefusedByMempoolAsync();
if (round.CountAlices() >= round.AnonymitySet)
{
await round.ExecuteNextPhaseAsync(CcjRoundPhase.ConnectionConfirmation);
}
}
var resp = new InputsResponse
{
UniqueId = alice.UniqueId,
BlindedOutputSignature = signature,
RoundId = round.RoundId
};
return(Ok(resp));
}
catch (Exception ex)
{
Logger.LogDebug <ChaumianCoinJoinController>(ex);
return(BadRequest(ex.Message));
}
}
}
