public static void VerifyTransaction(Transaction tx, DateTime timestamp, ulong coinbase = 0)
{
if (tx.TimeStamp > timestamp ||
!(coinbase == 0 ^ tx.Inputs.Count == 0))
{
throw new ArgumentException();
}
var hash = HashUtil.ComputeTransactionSignHash(JsonSerializer.Serialize(tx));
//Input check
var inSum = coinbase;
foreach (var input in tx.Inputs)
{
var chainTxs = Chain.SelectMany(x => x.Transactions);
//Input Verify
var transactions = chainTxs as Transaction[] ?? chainTxs.ToArray();
var prevOutTx = transactions
.First(x => x.Id.Bytes == input.TransactionId.Bytes)?
.Outputs[input.OutputIndex];
var verified = prevOutTx != null && SignManager.Verify(hash, input.Signature, input.PublicKey, prevOutTx.PublicKeyHash);
//utxo check ブロックの長さに比例してコストが上がってしまう問題アリ
var utxoUsed = transactions.SelectMany(x => x.Inputs).Any(ipt => ipt.TransactionId.Bytes != input.TransactionId.Bytes);
var redeemable = prevOutTx.PublicKeyHash.IsEqual(HashUtil.RIPEMD_SHA256(input.PublicKey));
inSum = checked (inSum + prevOutTx.Amount);
if (!verified || utxoUsed || !redeemable)
{
throw new ArgumentException();
}
}
ulong outSum = 0;
foreach (var output in tx.Outputs)
{
if (output.PublicKeyHash is null || output.Amount <= 0)
{
throw new ArgumentException();
}
outSum = checked (outSum + output.Amount);
}
if (outSum > inSum)
{
throw new ArgumentException();
}
tx.TransactionFee = inSum - outSum;
}
public Transaction ToSignedTransaction(byte[] privateKey, byte[] publicKey)
{
_transaction.TimeStamp = DateTime.UtcNow;
_transaction.Id = null;
foreach (var inEntry in Inputs)
{
inEntry.PublicKey = null;
inEntry.Signature = null;
}
var hash = HashUtil.ComputeTransactionSignHash(JsonSerializer.Serialize(_transaction));
var signature = SignManager.Signature(hash, privateKey, publicKey);
foreach (var inEntry in Inputs)
{
inEntry.PublicKey = publicKey;
inEntry.Signature = signature;
}
var txData = JsonSerializer.Serialize(_transaction);
var txHash = HashUtil.DoubleSHA256(txData);
_transaction.Id = new HexString(txHash);
return(_transaction);
}