/// <summary>
/// </summary>
/// <param name="transaction"></param>
/// <returns></returns>
public async Task <VerifyResult> VerifyOutputCommitments(Transaction transaction)
{
Guard.Argument(transaction, nameof(transaction)).NotNull();
var offSets = transaction.Vin.Select(v => v.Key).SelectMany(k => k.Offsets.Split(33)).ToArray();
var list = offSets.Where((value, index) => index % 2 == 0).ToArray();
foreach (var commit in list)
{
var blocks = await _unitOfWork.HashChainRepository.WhereAsync(x =>
new ValueTask <bool>(x.Txs.Any(v => v.Vout.Any(c => c.C.Xor(commit)))));
if (!blocks.Any())
{
return(VerifyResult.UnableToVerify);
}
var outputs = blocks.SelectMany(block => block.Txs).SelectMany(x => x.Vout);
if (outputs.Where(output => output.T == CoinType.Coinbase && output.T == CoinType.Fee)
.Select(output => VerifyLockTime(new LockTime(Utils.UnixTimeToDateTime(output.L)), output.S))
.Any(verified => verified != VerifyResult.UnableToVerify))
{
return(VerifyResult.UnableToVerify);
}
}
return(VerifyResult.Succeed);
}
/// <summary>
/// </summary>
/// <param name="transaction"></param>
/// <returns></returns>
public VerifyResult VerifyBulletProof(Transaction transaction)
{
Guard.Argument(transaction, nameof(transaction)).NotNull();
Guard.Argument(transaction.Vout, nameof(transaction)).NotNull();
try
{
if (transaction.Validate().Any())
{
return(VerifyResult.UnableToVerify);
}
using var secp256K1 = new Secp256k1();
using var bulletProof = new BulletProof();
if (transaction.Bp.Select((t, i) => bulletProof.Verify(transaction.Vout[i + 2].C, t.Proof, null))
.Any(verified => !verified))
{
return(VerifyResult.UnableToVerify);
}
}
catch (Exception ex)
{
_logger.Here().Error(ex, "Unable to verify the bullet proof");
return(VerifyResult.UnableToVerify);
}
return(VerifyResult.Succeed);
}
/// <summary>
///
/// </summary>
/// <param name="transaction"></param>
/// <returns></returns>
public async Task <VerifyResult> VerifyTransaction(Transaction transaction)
{
Guard.Argument(transaction, nameof(transaction)).NotNull();
if (transaction.Validate().Any())
{
return(VerifyResult.UnableToVerify);
}
var verifySum = VerifyCommitSum(transaction);
if (verifySum == VerifyResult.UnableToVerify)
{
return(verifySum);
}
var verifyBulletProof = VerifyBulletProof(transaction);
if (verifyBulletProof == VerifyResult.UnableToVerify)
{
return(verifyBulletProof);
}
var transactionTypeArray = transaction.Vout.Select(x => x.T.ToString()).ToArray();
if (transactionTypeArray.Contains(CoinType.Fee.ToString()) &&
transactionTypeArray.Contains(CoinType.Coin.ToString()))
{
var verifyVOutCommits = await VerifyOutputCommitments(transaction);
if (verifyVOutCommits == VerifyResult.UnableToVerify)
{
return(verifyVOutCommits);
}
}
var verifyKImage = await VerifyKeyImage(transaction);
if (verifyKImage == VerifyResult.UnableToVerify)
{
return(verifyKImage);
}
using var mlsag = new MLSAG();
for (var i = 0; i < transaction.Vin.Length; i++)
{
var m = Makemlsag(transaction.Rct[i].M, transaction.Vout, transaction.Vin[i].Key.Offsets,
transaction.Mix, 2);
var verifymlsag = mlsag.Verify(transaction.Rct[i].I, transaction.Mix, 2, m,
transaction.Vin[i].Key.Image, transaction.Rct[i].P, transaction.Rct[i].S);
if (verifymlsag)
{
continue;
}
_logger.Here()
.Fatal("Unable to verify the Multilayered Linkable Spontaneous Anonymous Group transaction");
return(VerifyResult.UnableToVerify);
}
return(VerifyResult.Succeed);
}
/// <summary>
/// </summary>
/// <param name="transaction"></param>
/// <returns></returns>
public async Task <VerifyResult> VerifyKeyImage(Transaction transaction)
{
Guard.Argument(transaction, nameof(transaction)).NotNull();
if (transaction.Validate().Any())
{
return(VerifyResult.UnableToVerify);
}
foreach (var vin in transaction.Vin)
{
var blocks = await _unitOfWork.HashChainRepository.WhereAsync(x =>
new ValueTask <bool>(x.Txs.Any(t => t.Vin.First().Key.Image.Xor(vin.Key.Image))));
if (blocks.Count > 1)
{
return(VerifyResult.UnableToVerify);
}
}
return(VerifyResult.Succeed);
}
/// <summary>
/// </summary>
/// <param name="transaction"></param>
/// <returns></returns>
public VerifyResult VerifyCommitSum(Transaction transaction)
{
Guard.Argument(transaction, nameof(transaction)).NotNull();
try
{
if (transaction.Validate().Any())
{
return(VerifyResult.UnableToVerify);
}
using var pedersen = new Pedersen();
for (var i = 0; i < transaction.Vout.Length / 3; i++)
{
var fee = transaction.Vout[i].C;
var payment = transaction.Vout[i + 1].C;
var change = transaction.Vout[i + 2].C;
var commitSumBalance = pedersen.CommitSum(new List <byte[]> {
fee, payment, change
},
new List <byte[]>());
if (!pedersen.VerifyCommitSum(new List <byte[]> {
commitSumBalance
},
new List <byte[]> {
fee, payment, change
}))
{
return(VerifyResult.UnableToVerify);
}
}
}
catch (Exception ex)
{
_logger.Here().Error(ex, "Unable to verify the committed sum");
return(VerifyResult.UnableToVerify);
}
return(VerifyResult.Succeed);
}
/// <summary>
/// </summary>
/// <param name="transaction"></param>
/// <returns></returns>
public VerifyResult VerifyTransactionFee(Transaction transaction)
{
Guard.Argument(transaction, nameof(transaction)).NotNull();
var output = transaction.Vout.First();
if (output.T != CoinType.Fee)
{
return(VerifyResult.UnableToVerify);
}
var feeRate = Fee(FeeNByte);
if (output.A != feeRate)
{
return(VerifyResult.UnableToVerify);
}
using var pedersen = new Pedersen();
var commitSum = pedersen.CommitSum(new List <byte[]> {
output.C
}, new List <byte[]> {
output.C
});
return(commitSum == null ? VerifyResult.Succeed : VerifyResult.UnableToVerify);
}