public bool IsChainValid()
{
Dictionary <string, TransactionOutput> tempUnspentTransactionOutputList = new Dictionary <string, TransactionOutput>(); //a temporary working list of unspent transactions at a given block state.
tempUnspentTransactionOutputList.Add(BlockChain[0].TransactionData[0].OutputList[0].Id, BlockChain[0].TransactionData[0].OutputList[0]);
for (int i = 1; i < BlockChain.Count; i++)
{
Block currentBlock = BlockChain[i];
Block previousBlock = BlockChain[i - 1];
if (currentBlock.CurrentBlockHash != currentBlock.CalculateHash())
{
Console.WriteLine("#Block Hash is not equal : Block(" + i + ")");
return(false);
}
if (currentBlock.PreviousBlockHash != previousBlock.CurrentBlockHash)
{
Console.WriteLine("#Block Previous Hash is not equal : Block(" + i + ")");
return(false);
}
TransactionOutput tempOutput;
for (int t = 0; t < currentBlock.TransactionData.Count; t++)
{
Transaction currentTransaction = currentBlock.TransactionData[t];
if (!currentTransaction.VerifiySignature())
{
Console.WriteLine("!!! - Signature on Transaction(" + t + ") is Invalid");
return(false);
}
if (currentTransaction.GetInputsValue() != currentTransaction.GetOutputsValue())
{
Console.WriteLine("!!! - Inputs are note equal to outputs on Transaction(" + t + ")");
return(false);
}
foreach (TransactionInput input in currentTransaction.InputList)
{
tempOutput = tempUnspentTransactionOutputList[input.TransactionOutputId];
if (tempOutput == null)
{
Console.WriteLine("!!! - Referenced input on Transaction(" + t + ") is Missing");
return(false);
}
if (input.UnspentTxOutput.Amount != tempOutput.Amount)
{
Console.WriteLine("!!! - Referenced input Transaction(" + t + ") value is Invalid");
return(false);
}
tempUnspentTransactionOutputList.Remove(input.TransactionOutputId);
}
foreach (TransactionOutput output in currentTransaction.OutputList)
{
tempUnspentTransactionOutputList.Add(output.Id, output);
}
if (currentTransaction.OutputList[0].Receiver != currentTransaction.Receiver)
{
Console.WriteLine("!!! - Transaction(" + t + ") output receiver is not who it should be");
return(false);
}
if (currentTransaction.OutputList[1].Receiver != currentTransaction.Sender)
{
Console.WriteLine("!!! - Transaction(" + t + ") output 'change' is not sender.");
return(false);
}
}
}
return(true);
}
