public bool Verify(NormalTransaction tx)
{
/*
* bool flag = false;
* for(int i = 0;i<leavesNumber;i++)
* {
* if (tx.id == tree[i])
* {
* flag = true;
* break;
* }
* }
* if (flag == false) return false;
*/
return(true);
}
public bool Transfer(Blockchain bc, byte[] sender, byte[] receiver, int amount)
{
//calculate inputs
List <TxIn> tx_ins = new List <TxIn>();
int tx_in_amount_count = 0;
foreach (KeyValuePair <TxIn, int> unspend_tx_out in bc.FindUnspendTxOut(sender))
{
if (tx_in_amount_count < amount)
{
tx_in_amount_count += unspend_tx_out.Value;
tx_ins.Add(unspend_tx_out.Key);
}
else
{
break;
}
}
if (tx_in_amount_count < amount)
{
Console.WriteLine("Not enough money");
return(false);
// not enough money in the account
}
TxOut[] outputs;
//calculate ouputs
if (tx_in_amount_count > amount)
{
outputs = new TxOut[2];
outputs[1] = new TxOut();
outputs[1].address = sender;
outputs[1].amount = tx_in_amount_count - amount;
}
else
{
outputs = new TxOut[1];
}
outputs[0] = new TxOut();
outputs[0].address = receiver;
outputs[0].amount = amount;
NormalTransaction tx = new NormalTransaction(tx_ins.ToArray(), outputs, key);
return(bc.CommitTransaction(tx));
}
public bool CommitTransaction(NormalTransaction tx)
{
//make sure the id is exactly the hash of the transaction
if (!Program.CompareBytes(tx.id, Crypto.CalculateSHA256(tx)))
{
Console.WriteLine("Transaction ID verification failed");
return(false);
}
bool found_flag;
//make sure the TxIn is avaliable
foreach (TxIn txIn in tx.inputs)
{
found_flag = false;
for (int i = 1; i < blocks.Count; i++)
{
//find out if the txIn point to an awardTransaction
if (txIn.outIndex == 0 && Crypto.VerifyHash(tx.id, tx.signature, blocks[i].awardTransaction.output.address))
{
found_flag = true;
break;
}
foreach (NormalTransaction _tx in blocks[i].transactions)
{
if (Program.CompareBytes(_tx.id, txIn.outId))
{
if (_tx.outputs.Length > txIn.outIndex && Crypto.VerifyHash(tx.id, tx.signature, _tx.outputs[txIn.outIndex].address))
{
found_flag = true;
}
else
{
return(false);
}
}
if (found_flag)
{
break;
}
}
if (found_flag)
{
break;
}
}
if (!found_flag)
{
return(false); //no found corresponding txOut of the txIn in blockchain
}
}
//provent double spend attack
foreach (NormalTransaction _tx in transactions)
{
foreach (TxIn _txIn in _tx.inputs)
{
foreach (TxIn txIn in tx.inputs)
{
if (_txIn == txIn)
{
return(false);
}
}
}
}
transactions.Add(tx);
return(true);
}
