public string CalculateHash()
{
string fromAddressDER = BitConverter.ToString(FromAddress.toDer()).Replace("-", "");
string toAddressDER = BitConverter.ToString(ToAddress.toDer()).Replace("-", "");
string transactionData = fromAddressDER + toAddressDER + Amount;
byte[] tdBytes = Encoding.ASCII.GetBytes(transactionData);
return(BitConverter.ToString(SHA256.Create().ComputeHash(tdBytes)).Replace("-", ""));
}