public static void ValidateBlock(Block block)
{
// first validate the Nonce matches the difficulty mask
string mineHash = Sha256Hash.Hash(BitConverter.GetBytes(block.Nonce), block.PreviousBlockHash);
if (!Regex.IsMatch(mineHash, block.DifficultyMask))
{
throw new Exception("Nonce does not match difficulty mask");
}
for (int i = 0; i < block.Transactions.Count; i++)
{
Transaction t = block.Transactions[i];
TransactionValidatorService.ValidateTransaction(t);
}
}
public static void ValidateTransaction(Transaction transaction)
{
bool isCoinbase = transaction.Inputs.Count == 0;
decimal
totalInput = 0,
totalOutput = 0;
// verify the inputs are able to be spent with the public key the transaction is signed with
for (int i = 0; i < transaction.Inputs.Count; i++)
{
TransactionInput txIn = transaction.Inputs[i];
Transaction lastTxInTrans = TransactionFactory.TransactionFromTxInput(txIn);
TransactionOutput lastTxInOutput = lastTxInTrans.Outputs.ElementAt((int)txIn.PreviousTransactionOutIndex);
if (!transaction.VerifySignature(lastTxInOutput.To))
{
throw new Exception("Transaction sign chain is invalid");
}
TransactionValidatorService.ValidateTransaction(lastTxInTrans);
totalInput += lastTxInOutput.Amount;
}
if (isCoinbase)
{
if (transaction.Inputs.Count != 1 && transaction.Outputs.Count != 1)
{
throw new Exception("Coinbase transaction must have one input and one output");
}
return;
}
for (int i = 0; i < transaction.Outputs.Count; i++)
{
TransactionOutput txOut = transaction.Outputs[i];
totalOutput += txOut.Amount;
}
if (!isCoinbase && totalOutput > totalInput)
{
throw new Exception("Output must not exceed input");
}
}